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Title: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 09:38:17 am
So here is what i'm thinking about now. I'm working in an underground club that can fit about 800-900 people. I do sound for some live shows and for most of the electronic parties/events. Most of them are techno/dnb/dub parties.
The venue itself is a big concrete basement, needs some serous acoustical treatment but there is no money for it so the room itself sounds like shit. Loads of reverb, agressive sharpness in 1-5k range, huge sub coverage problems. Enough power from the PA but very uneven sub coverage.

The equipment i'm working with here is 4x yamaha cw218v subs and 6x yamaha c215v tops. 7X yamaha p7000s amps (2 for monitors), dbx 2231 EQ and a behringer x32. I use matrix sends on the behringer as a crossover and by doing that i can, if i want, have separated control over each box of the PA.

Here is the only picture i have right now, if needed i can take more: 

https://scontent-vie1-1.xx.fbcdn.net/hphotos-xlf1/v/t1.0-9/12390892_1713073048924548_710351901504307360_n.jpg?oh=5d76f3f6a896e70690df5be245a1e52d&oe=57388C53

Now, when we do bigger parties we sometimes rent a sub array of a few hog scoops with some really good B&C drivers inside and with a few kickers on top of them. 2-way sub array, works really good compared to the sloppy soft sounding yamaha subs. However i still have to do most of the parties with the yamaha system.
I have found the best way to eq the system and tried the mono block setup with the subs that works better then saparated stereo blocks like in the picture.

However the room has big problems with getting rid of the sub once those boxes push it out. There is no bass traps, it takes a few seconds for the sub to dissapear from the room once you stop the subs, there is more sub in the backstage then in front of the stage and so on...

What i have been thinking about is trying to control this as much as i can. If i succeed in stopping sub energy from hitting the walls behind the stage and reflecting back into the room + if there is a way to control the way they push sub into the room i might be able to make sub more precise, tighter and avoid the shaking/resonating noises of some elements in the room.

I had 3 ideas so far.

1.
Standard cardioid mono block. Two boxes normal, 2 boxes pointing backwards, delayed with inverted polarity. This setup would give me absolute cancelation on the stage but i would loose some quallity and power in front witch i don't want since these 4 subs are barely enough to give me what i want in front. But i don't know what exactly i'm going to get with this setup so i will try it. 

2. Cardioid mono block where i have 3 boxes pointing outwards and one backwards. This will give me the simmilar result as the option one but with less lost in front of the subs.

3. 2/2 Cardioid but with all 4 subs standing upright and the outer 2 ones being turned around and set to cancel out what comees out the back.
So the subs would look like this:

https://scontent-vie1-1.xx.fbcdn.net/hphotos-xpf1/t31.0-8/12248049_1703600613205125_4654010210678630930_o.jpg

but with only the center two ones pointing forward. The reason i have been thinking about this setup is because i'm wondering if like this i can control what goes of to the left and right side of the array, not just the back ??

4.
Cardioid endfire array. Getting al 4 subs on stage but 2 behind 2 or even all 4 in line one behind one. With this i could get perfect cancelation on the most problematic frequency but not on the other ones. However i wouldn't loose nothing in front, compared to the normal mono block. So this might be the best option maybe. What do you think?

And if you have more ideas i'd love to hear them :)
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim Steer on February 03, 2016, 11:02:36 am
I'd try an endfire array of two subs, with one placed 1/4 wavelength behind the other at whatever frequency you want the most cancellation. Then delay the front sub back to the second. I'd advise against putting it on the stage though to avoid mechanical transmission to microphones, turntables etc, and colouration from the stage cavity itself, esp if a solid stage.

E.g. for 63Hz, you'd need 1.35m between the front edges of the two subs, and a delay of 4.0ms on the front sub.

Note for this to work properly (as with any cardioid sub array) you need to leave a decent amount of space around the array.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 11:07:31 am
I'd try an endfire array of two subs, with one placed 1/4 wavelength behind the other at whatever frequency you want the most cancellation. Then delay the front sub back to the second. I'd advise against putting it on the stage though to avoid mechanical transmission to microphones, turntables etc, and colouration from the stage cavity itself, esp if a solid stage.

E.g. for 63Hz, you'd need 1.35m between the front edges of the two subs, and a delay of 4.0ms on the front sub.

Note for this to work properly (as with any cardioid sub array) you need to leave a decent amount of space around the array.

2 problems. First, i can't put an endfire configuration on the floor. It's going to be getting under the feet of people dancing and that's a big problem

No matter which solution i put on the floor, there is going to be a boundary about 10-20cm behind the subs. See the yellow/black edge of the stage? That's where the subs go when in mono block in front of the stage.

2. Even if they are on the stage, there is about maybe 3-4 meters of distance to the back wall of the stage. Is that enough for cancelation to happen?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim Steer on February 03, 2016, 12:34:49 pm
If it's acceptable to you to have the subs on stage then give it a go and see how it compares to your normal setup. My feeling is that they would take up too much space, annoy the musicians, potentially cause feedback issues and turn the stage (which from the photo looks like a wooden box of some sort) into one giant speaker.

Cardioid arrays are great in theory and work well outdoors in the free-field, but put one in a boxy reflective venue where room modes and reflections come into play, and tbh it's anyone's guess what will happen. I'd spend a couple of hours tinkering with different configurations and see how they perform.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 12:58:13 pm
If it's acceptable to you to have the subs on stage then give it a go and see how it compares to your normal setup. My feeling is that they would take up too much space, annoy the musicians, potentially cause feedback issues and turn the stage (which from the photo looks like a wooden box of some sort) into one giant speaker.

Cardioid arrays are great in theory and work well outdoors in the free-field, but put one in a boxy reflective venue where room modes and reflections come into play, and tbh it's anyone's guess what will happen. I'd spend a couple of hours tinkering with different configurations and see how they perform.

Well the thing is, when they are stacked in stereo blocks the problem of sub on stage is massive. I doubt it can be much worse in an endfire configuration. The stage is a concrete box, slightly treated with some wood but not much. Right now it's definitley one big speaker considered how much sub is reflected on it. But wouldn't the cardioid endfire array have a point of solving a part of that problem? That's the main reason i'm planning to try this. To cancel out what goes on stage and possibly in the sides. There is not going to be mics on stage and probably only cd players, but even if we put that aside my logics tell me that the point of an endfire configuration would be getting a part of that sub off the stage.

The only question now is witch cardioid config is going to work best which i will try in 2 weeks when the next party comes.

My fears now are... if i do a normal cardioid setup below the stage, the concrete yellow/black wall will be just behind the subs which might prevent proper cancelation because there won't be enough free space behind them.

And i don't know what do i do if i want to try and control the direction and angle under which the sub is projected in front of the stage. 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 03, 2016, 01:15:14 pm

Cardioid endfire array.
There is no such thing as a "cardioid endfire"

They are electonically different with different sonic and cancellation results.

If you do the math for a cardioid alignment- you will (or should) quickly realize that simply turning a "normal" cabinet around will NOT give you the spacing you need-except for freq that are higher than the sub range.

As with most things audio-SIZE matters. And with cardioid or endfire setups, you MUST space the cabinets properly and use the correct delay in order for it to work.

As soon as you start to change the delay OR the spacing, then the end result will ALSO change.  Sometimes not where you want it to.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 01:57:46 pm
There is no such thing as a "cardioid endfire"

They are electonically different with different sonic and cancellation results.

If you do the math for a cardioid alignment- you will (or should) quickly realize that simply turning a "normal" cabinet around will NOT give you the spacing you need-except for freq that are higher than the sub range.

As with most things audio-SIZE matters. And with cardioid or endfire setups, you MUST space the cabinets properly and use the correct delay in order for it to work.

As soon as you start to change the delay OR the spacing, then the end result will ALSO change.  Sometimes not where you want it to.

Isn't an endfire configuration just a type of a cardioid setup?

Yes of course i have to space them and delay them properly. That's not the question i asked.
I asked, if i take a normal cardioid array, one box pointing forwards, one pointing backwards, i invert the phase on the backwards pointing box and delay it as much as needed to get cancelation. And then put that array 15cm from a concrete wall, will the wall create problems and stop cancelation from occuring the way it should?
Do cardioid configurations need a certain amount of space behind them in order for waves to have enough space to cancel out? And if so, how much space is needed?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim McCulloch on February 03, 2016, 03:37:47 pm
Isn't an endfire configuration just a type of a cardioid setup?

Yes of course i have to space them and delay them properly. That's not the question i asked.
I asked, if i take a normal cardioid array, one box pointing forwards, one pointing backwards, i invert the phase on the backwards pointing box and delay it as much as needed to get cancelation. And then put that array 15cm from a concrete wall, will the wall create problems and stop cancelation from occuring the way it should?
Do cardioid configurations need a certain amount of space behind them in order for waves to have enough space to cancel out? And if so, how much space is needed?

Ideally, greater than 1/2 wave length.  I'm thrilled if I can get 1 metre or more in most venues.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 04:30:29 pm
Ideally, greater than 1/2 wave length.  I'm thrilled if I can get 1 metre or more in most venues.

So if'm doing an endfire array and want cancelation at 50hz i should have idealy about 3.5-4m of free space behind the sub array?
If i'm doing a normal cardioid array and want cancelation all the way down to 35hz i need even more...
What happens if i place a normal cardioid array 15cm away from a wall, it won't work even close to the way it should?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim McCulloch on February 03, 2016, 04:57:11 pm
So if'm doing an endfire array and want cancelation at 50hz i should have idealy about 3.5-4m of free space behind the sub array?
If i'm doing a normal cardioid array and want cancelation all the way down to 35hz i need even more...
What happens if i place a normal cardioid array 15cm away from a wall, it won't work even close to the way it should?

That is correct.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 05:13:06 pm
That is correct.

Great... seems like the setup is going to be on the stage for sure.

Consider another thing.
If all 4 boxes are below the stage and the concrete wall is covering them from the back side. Does that mean that all the sub going to the back side is going to be reflected away from the stage, back into the room or i will still be getting sub on the stage making a cardioid array a good option?

Another question. If i decide to go for a cardioid array with 3 boxes pointing forwards and one box pointing backwards. Can i do the following:
I put 3 boxes in the line on the stage just behing that metal bar that you can see in the picture of the club. Then the fourth backwards pointing sub should be on top of the middle sub of the 3 pointing forwards.
But, that would cover the dj... so can i take that fourth sub and put it behind the middle sub of the 3 on stage, flip it around, flip it's polarity, delay it and get a cardioid setup that way?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 03, 2016, 05:19:25 pm
Isn't an endfire configuration just a type of a cardioid setup?

Yes of course i have to space them and delay them properly. That's not the question i asked.
I asked, if i take a normal cardioid array, one box pointing forwards, one pointing backwards, i invert the phase on the backwards pointing box and delay it as much as needed to get cancelation. And then put that array 15cm from a concrete wall, will the wall create problems and stop cancelation from occuring the way it should?
Do cardioid configurations need a certain amount of space behind them in order for waves to have enough space to cancel out? And if so, how much space is needed?
It is NOT a matter of simply turning one box around.  You HAVE to have the radiating areas 1/4 WL apart at the freq of interest.

Let's say that your subs are 2' (0.6M) deep and you just turn one around

That means that 1/4 WL is 140Hz.  So unless you want the center freq of your sub cancellation at 140Hz-you need to space them further apart.

It is the proper spacing AND delay that makes the cancellation.

The 2 together =1/2 WL, which is the maximum cancellation.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 03, 2016, 05:24:54 pm

I put 3 boxes in the line on the stage just behing that metal bar that you can see in the picture of the club. the fourth backwards pointing sub should be on top of the middle sub of the 3 pointing forwards.

You MUST have physical distance between the fronts of the subs in order to work. 

Also by doing 3 forward and 1 rear-means that you will  not get anywhere nearly the amount of cancellation would get when you have the same number facing each direction.

You DO NOT have to have the rear sub facing backwards.  It can be facing forward-it just HAS to be far enough  BEHIND the front sub for the freq of interest.

As you go lower-you HAVE to increase the distance between the radiating area.  NO way around it.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 05:28:24 pm
It is NOT a matter of simply turning one box around.  You HAVE to have the radiating areas 1/4 WL apart at the freq of interest.

Let's say that your subs are 2' (0.6M) deep and you just turn one around

That means that 1/4 WL is 140Hz.  So unless you want the center freq of your sub cancellation at 140Hz-you need to space them further apart.

It is the proper spacing AND delay that makes the cancellation.

The 2 together =1/2 WL, which is the maximum cancellation.

??? By adding delay to the flipped box i am basically spacing them further apart. Almost all cardioid arrays look like this:  http://www.ratsound.com/cblog/uploads/2009_04_24_subs.jpg
The flipped box does not have to be physicaly moved from the front pointing boxes, it just needs to be delayed so it's wave gets perfectly out of phase with the backwave from the front pointing boxes.

If we are talking about the endfire array then no boxes are getting flipped around. They need to be spaced and delayed correctly yes but they are all firing in the same direction. 

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 03, 2016, 05:35:13 pm
You MUST have physical distance between the fronts of the subs in order to work. 

Also by doing 3 forward and 1 rear-means that you will  not get anywhere nearly the amount of cancellation would get when you have the same number facing each direction.

You DO NOT have to have the rear sub facing backwards.  It can be facing forward-it just HAS to be far enough  BEHIND the front sub for the freq of interest.

As you go lower-you HAVE to increase the distance between the radiating area.  NO way around it.

You have mixed things up. I'm not talking about doing a combination of an endfire array with some of the boxes turned around like in a cardiod array. I planed to do a normal endfire setup with all boxes pointing forwards and then pick a frequency that i want to cancel out and space+delay them considering that.

OR if that doesn't work well i will try a normal cardioid array, not the endfire one. In a normal cardioid array boxes are lined up but some of them are flipped, polarity inversed and delayed.

Also, by using a 2/2 normal cardioid setup the back facing subs will have to be turned down a few dB because less energy goes to the back of the sub array then to the front.
Witch means that in a 3/1 normal cardioid configuration one sub will be enough to cancel out most of the sub that goes back from the forward pointing 3 ones and therefore i will get decent cancelation and more power in the front.
With a 2/2 setup i'd loose to much power in the front.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Lee Wright on February 03, 2016, 06:29:54 pm
1.  I found a 2 element endfire array worked well for me for outdoor gigs but as mentioned may not work so well indoor.  I had both my subs pointing forward but but the phase inverted on the back one but I didn't have much spacing between them - maybe only about a foot.

2. It looks  from the picture like it's in a corner.  Is that corner less than 90 degrees?  I did a venue where it was about 70 degrees & had real problems with the sub.  I had to pull them out of the corner & put them against one wall near the left FOH & that worked well.

3. There's an interesting under-stage, end-fire array that was used for Carrie Underwood that apparently worked well but I haven't tried it. details here:
http://forums.prosoundweb.com/index.php?topic=1015.0

4 I've had subs work well under the stage & it cuts down on the bass that the band gets.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 03, 2016, 07:11:31 pm
??? By adding delay to the flipped box i am basically spacing them further apart.
NO

You need to read up on how the physical spacing works WITH the delay.

You CANNOT change one and "make up" for the other.

The physical spacing ALONE will determine what the "center freq" of the cancellation is.

Something else to consider-that many people are not aware of.

A "cardioid" setup will have less "punch" than an endfire setup.

This is due to the cancellation of the upper freq of the bass region.

An endfire will not have this cancellation (and therefore will have a more natural sound), but an endfire does not have as much rejection to the rear.

You MUST decide what is most important-rear rejection or sound quality.

You DO NOT get both.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 03, 2016, 07:14:00 pm
Almost all cardioid arrays look like this:  http://www.ratsound.com/cblog/uploads/2009_04_24_subs.jpg

And when you "do the math" you will find that the cancellation does not extend real low-simply due to the small spacing.

You cannot "cheat" the physics.

You never see any measurements to prove how well it works.

In many cases they are setup that way for convenience or it is all you can do in the space provided.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Len Zenith Jr on February 04, 2016, 04:05:26 am
The physical spacing ALONE will determine what the "center freq" of the cancellation is.

How far either side of the "center freq" will cancellation occur for these configurations? 1/4 octave? 1/2 octave? I understand it would be a curve but what would be the Q of that curve? I'm sure "it depends" but some insight would be helpful.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 04, 2016, 05:47:28 am
NO

You need to read up on how the physical spacing works WITH the delay.

You CANNOT change one and "make up" for the other.

The physical spacing ALONE will determine what the "center freq" of the cancellation is.

Something else to consider-that many people are not aware of.

A "cardioid" setup will have less "punch" than an endfire setup.

This is due to the cancellation of the upper freq of the bass region.

An endfire will not have this cancellation (and therefore will have a more natural sound), but an endfire does not have as much rejection to the rear.

You MUST decide what is most important-rear rejection or sound quality.

You DO NOT get both.

Wait, so if i understood you well, you are saying that, in a normal cardioid array, like the one in the picture. The setup would benefit if the flipped box was taken out of the array and pushed slightly behind it depending on which frequency you want to cancel out the most? Do you have any good literature on this, i'd like to read. I read the entire "subwoofer arrays" pdf from electro voice but there is nothing about this there.
I can't understand why this would be true simply because the flipped box is pushing out everything that i's getting back from the front pointing boxes, just in the opposite phase. Witch means it provides perfect cancelation on all frequencies. That is the point of a normal cardioid array.

However i do see some sense in moving the flipped box physicaly behind because the sound that goes on the back side of the flipped box will collide with the sound coming out of the front of the front pointing boxes. It of course won't be in phase with it which will decrease the sub quallity in front. But by moving the flipped box i could control how sound going back from the flipped box collides with what comes out of the front of fron pointing boxes.

I'm not saying i'm right, this is just what makes sanse to me based on my current knowledge. If you cold explain more that would be great.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim Steer on February 04, 2016, 06:34:36 am
It's a fairly common technique. Space the speakers 1/4 of a wavelength at the offending frequency and delay the front speaker by 1/4 of a wave period.

Consider what happens when a sine wave is played through the system at that frequency...

In front of the array: The front sub 'waits' for the wavefront to from the rear sub to 'catch up' before firing - the sound from both subs is in phase and adds constructively.

Behind the array: The wavefront from the rear sub reaches the listener first. The sound from the front sub is delayed by 1/4 of a period, and THEN has to travel and extra 1/4 wavelength - a total time delay of 1/2 a period. The result is that the waves from the two subs are 1/2 a period out of phase, and add destructively.

I've set up two configurations of L'Acoustics subs side-by-side - the L'Acoustics recommended method, with bottom sub reversed and in 'C' mode, and an endfire array as described above, and whilst the 'stacked' method worked pretty well, the endfire array offered much greater rear rejection.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 04, 2016, 06:37:49 am
It's a fairly common technique. Space the speakers 1/4 of a wavelength at the offending frequency and delay the front speaker by 1/4 of a wave period.

Consider what happens when a sine wave is played through the system at that frequency...

In front of the array: The front sub 'waits' for the wavefront to from the rear sub to 'catch up' before firing - the sound from both subs is in phase and adds constructively.

Behind the array: The wavefront from the rear sub reaches the listener first. The sound from the front sub is delayed by 1/4 of a period, and THEN has to travel and extra 1/4 wavelength - a total time delay of 1/2 a period. The result is that the waves from the two subs are 1/2 a period out of phase, and add destructively.

I've set up two configurations of L'Acoustics subs side-by-side - the L'Acoustics recommended method, with bottom sub reversed and in 'C' mode, and an endfire array as described above, and whilst the 'stacked' method worked pretty well, the endfire array offered much greater rear rejection.

Yes, that's an endfire array. That's not what we are talking about now. He told me that a normal cardioid array benefits if the box that is flipped around is pushed behind the array. I know how an endfire array works.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 04, 2016, 08:11:44 am
There is a confusion of terminology going on here.

A "cardioid" array is where the rear box (facing in EITHER direction) is delayed and has the polarity flipped.

This can be done by turning the rear box around or physically placing it behind the front box.  Either way-the PHYSICAL DISTANCE is the determining factor for the center of cancellation (maximum cancellation) frequency.

An endfire array is where the rear box has no delay and each box towards the front is progressively delayed.

A cardioid setup can only have 2 boxes.  Yes you can use more-but there are only 2 settings that are used.

And endfire can use as many as you want.


The sonic differences are as follows.

In NEITHER cases will the output SPL output out front be equal to the same number of boxes simply facing forward.

It will be always be lower.  Remember you are CANCELLING energy.  You don't get that back.

The cardioid will have more rear rejection at the expense of upper bass rolloff.  This can result in less "punch".

The endfire will have less rear rejection, but will sound like a single cabinet.  So sonically it is better
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 04, 2016, 08:17:22 am

I can't understand why this would be true simply because the flipped box is pushing out everything that i's getting back from the front pointing boxes, just in the opposite phase. Witch means it provides perfect cancelation on all frequencies. That is the point of a normal cardioid array.


Any cancellation by any loudspeaker is freq dependant.

You do not get cancellation across the entire bandwith.

It is all position related.

I don't have the time right now to show you some examples, but can do so later-along with models and freq response .

If you read up on how an endfire or cardioid system works, you should start to get a better understanding that it IS physical distance and freq related.

It is NOT across the whole freq range. No matter what anybody says.  If they tell you that-they are wrong.  Sorry.

Unless the freq range is pretty small.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 04, 2016, 09:56:39 am
There is a confusion of terminology going on here.

A "cardioid" array is where the rear box (facing in EITHER direction) is delayed and has the polarity flipped.

This can be done by turning the rear box around or physically placing it behind the front box.  Either way-the PHYSICAL DISTANCE is the determining factor for the center of cancellation (maximum cancellation) frequency.

An endfire array is where the rear box has no delay and each box towards the front is progressively delayed.

A cardioid setup can only have 2 boxes.  Yes you can use more-but there are only 2 settings that are used.

And endfire can use as many as you want.


The sonic differences are as follows.

In NEITHER cases will the output SPL output out front be equal to the same number of boxes simply facing forward.

It will be always be lower.  Remember you are CANCELLING energy.  You don't get that back.

The cardioid will have more rear rejection at the expense of upper bass rolloff.  This can result in less "punch".

The endfire will have less rear rejection, but will sound like a single cabinet.  So sonically it is better

Yes there is a big terminology confusion going here.

In no part of the text i have been talking about about an array where boxes are set one behind another AND some of them are polarity flipped. 

I have been comparing different variations of:  A normal endfire setup where a few boxes are standing one behind another, working in phase, delayed and spaced properly, canceling out ony one frequency perfectly.

And then i have been talking about a cardioid setup. BUT NOT an endfire cardioid setup. I'm talking about a normal, sandard cardioid setup that looks like this:

http://www.ratsound.com/cblog/uploads/2009_04_24_sub_center.jpg

or this:

api.ning.com/files/K5EyQbUmZFDOihL3vM7IYLPZ5*wRx8ADuEJifX4wDkC5HNqJsK0DOvQqBhERjLzhesSxAoooibjO61fcKRj48nubAhTSIqfg/ScreenShot20131001at11.13.31PM.png

or this:

http://www.creativeaudio.us/images/audio/audio4.jpg


In all setups where some of the boxes are turned around, polarity flipped and delayed cancelation occurs at all frequencies. They don't need to be physicaly moved, that makes no sense.
 
However what i think you are talking about is a variation of the endfire setup where the back box is polarity flipped and optimized for maximum cancelation.
I know how that works but i have not talked about that array anywhere in the subject.

Because you wrote:

A "cardioid" array is where the rear box (facing in EITHER direction) is delayed and has the polarity flipped.

There is no rear box in any of the cardioid arrays i have mentioned. The rear box exist only in a normal endfire configuration where all boxes work in phase and point in the same direction.

I am basicaly comparing this: https://www.gearslutz.com/board/attachments/remote-possibilities-acoustic-music-location-recording/296739d1339981762-need-advise-meyer-setup-array.jpg

Versus this:  http://i39.photobucket.com/albums/e194/HarfordSound/cardioidB2.jpg
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 04, 2016, 12:18:30 pm

I have been comparing different variations of:  A normal endfire setup where a few boxes are standing one behind another, working in phase, delayed and spaced properly, canceling out ony one frequency perfectly.





In all setups where some of the boxes are turned around, polarity flipped and delayed cancelation occurs at all frequencies. They don't need to be physicaly moved, that makes no sense.
 

WRONG WRONG WRONG

No matter how much you "want" to believe it, you MUST have spacing AND it is NOT cancellation across the whole freq band.

I would LOVE to see any simulation or measurement to prove other wise.

I have done BOTH types of setups and MEASURED AND SIMULATED IT, and in NO case did I get cancellation across the whole freq range.

And in EVERY case-the spacing of the boxes made a difference of what freq were affected (ie cancelled)

DO THE MATH (it is very simple) and change things and you can prove it to yourself.

Or you can go on "make believing" that what you think is actually happening.

Sorry to sound rude-but it is evident that you have no practical knowledge or experience with either setup.



Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 04, 2016, 12:38:59 pm
WRONG WRONG WRONG

No matter how much you "want" to believe it, you MUST have spacing AND it is NOT cancellation across the whole freq band.

I would LOVE to see any simulation or measurement to prove other wise.

I have done BOTH types of setups and MEASURED AND SIMULATED IT, and in NO case did I get cancellation across the whole freq range.

And in EVERY case-the spacing of the boxes made a difference of what freq were affected (ie cancelled)

DO THE MATH (it is very simple) and change things and you can prove it to yourself.

Or you can go on "make believing" that what you think is actually happening.

Sorry to sound rude-but it is evident that you have no practical knowledge or experience with either setup.

I have no practical knowledge but you are not explaining yours claims either so i don't see how you expect me to see logics in them after seeing normal cardioid arrays with no box spacing at almost every festival where cardioid arrays are used.

Here is a simulation of a cardioid array at 2:10 : 

https://www.youtube.com/watch?v=nddK_zsGraM   

Cancels out everything up to 80hz almost perfectly eaven. After that the cancelation starts dropping of course but we are not talking about sub anymore.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 04, 2016, 01:19:31 pm
I have no practical knowledge but you are not explaining yours claims either so i don't see how you expect me to see logics in them after seeing normal cardioid arrays with no box spacing at almost every festival where cardioid arrays are used.

Here is a simulation of a cardioid array at 2:10 : 

https://www.youtube.com/watch?v=nddK_zsGraM   

Cancels out everything up to 80hz almost perfectly eaven. After that the cancelation starts dropping of course but we are not talking about sub anymore.
Think about it this way.

What are the STEPS in doing a directional sub array (either type)

STEP 1 Determine what the 1/4 wavelength distance is for the freq of interest.

If this didn't matter-then WHY is it STEP 1?

You CANNOT go to step 2 until you have done STEP 1.

Yes you don't HAVE to figure out step one-but there ARE consequencies.

For example-if you just turn one sub around and let's say it is 2' deep.

You set your delay for around 2ms.

Sure you will get cancellation behind- BUT ALSO there will be LESS SOUND out front than if you just used ONE speaker-at certain freq.

There ARE tradeoffs, and you have to realize there is no "free lunch".

But people often like to "forget" the things that they don't want to talk about.

It just makes their case "stronger".

But it is the OVERALL situation that should be considered-NOT just one little aspect.  But if that is all you want to consider-then sure-it is fine.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Jay Barracato on February 04, 2016, 02:50:51 pm
Eugen,

A couple of reality points. I understand what you are trying to ask without forcing absolutes onto your words which really aren't helping.

I have set up the two forward/one reversed setup you are asking about any number of times. These comments are based on my observations and measurements.

1. The best center frequency cancellation I achieved was about -18 db at 70 hz in open air. 12-15 db is much more typical.

2. This comes with a 3-6 db reduction out front that is delayed by 1 wave. You still have the initial impact on the initial wave.

3 The cancellation tapers off (as you asked) as you move outward from the center frequency. This is because of the range of phase angles around 180 where cancellation occurs.

4. The rate at which the cancellation falls off depends on the phase response from f the speakers. The steeper the change in phase of the speakers, the narrower the frequency range that will cancel is.

5. Indoors primary reflections from walls especially at the back of the stage throw a monkey wrench into all this and really affect what is heard at each listening position.

I work every week in a similar 700 capacity club and my inclination would be to use bass traps to control low end reflections on stage rather than trying to create a zone of cancellation.

If you go to www.bennettprescott.com
He has a couple of articles posted about smaller subwoofer arrays.


Sent from my XT1254 using Tapatalk
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 04, 2016, 06:59:09 pm
Eugen,

A couple of reality points. I understand what you are trying to ask without forcing absolutes onto your words which really aren't helping.

I have set up the two forward/one reversed setup you are asking about any number of times. These comments are based on my observations and measurements.

1. The best center frequency cancellation I achieved was about -18 db at 70 hz in open air. 12-15 db is much more typical.

2. This comes with a 3-6 db reduction out front that is delayed by 1 wave. You still have the initial impact on the initial wave.

3 The cancellation tapers off (as you asked) as you move outward from the center frequency. This is because of the range of phase angles around 180 where cancellation occurs.

4. The rate at which the cancellation falls off depends on the phase response from f the speakers. The steeper the change in phase of the speakers, the narrower the frequency range that will cancel is.

5. Indoors primary reflections from walls especially at the back of the stage throw a monkey wrench into all this and really affect what is heard at each listening position.

I work every week in a similar 700 capacity club and my inclination would be to use bass traps to control low end reflections on stage rather than trying to create a zone of cancellation.

If you go to www.bennettprescott.com
He has a couple of articles posted about smaller subwoofer arrays.


Sent from my XT1254 using Tapatalk

Thanks.
So if i understood this right, with a standard cardioid array i also pick the most problematic frequency and tune the array according to that?
It will of course give me more overall 30-100hz cancelation than an endfire array witch will be effective only around one frequency. But i still have to pick the area that creates the most problems because i can't cancel out everything.

How do i set up a standard cardioid then? I flip one box, flip it's polarity, and then i delay it how much? I tought i need to find the time that sub from the front boxes needs for reaching their back side/the front side of the flipped box.
I didn't think that this time was frequency dependant?

Also i can't improvise bass traps. It's not my club, i won't invest my money in acoustical treatment of a club i only work in.

And yeah, the sub from the flipped box that is getting back in front will be out of phase and delayed in comparison to the sub from the boxes radiating directly into the room, witch will decrease the quallity of what goes in front, right?
And talking about power, when i flip one box in a mono block to make a cardioid array, i quiet much loose most of the power, if not all of the power from that box if talking about what i'm getting outside. That sub that goes to the back side of the flipped box is going to be late and do more damage than good right?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Jay Barracato on February 04, 2016, 07:59:11 pm
First of all any box used to create cancellation is going to reduce the level compared to using that box as part of the forward signal.

You are making this overly complicated by continuing to try and compare techniques. There really is no difference in how the two techniques work.

Turn it around and for a moment consider this from a standpoint of a listening position. Cancellation occurs when two waves near the same size in magnitude arrive at the listening near 180 degrees from each other.

All sound waves are moving at the same speed so time and distance are the same thing. Forget about spacing, forget about polarity, forget about delay. All those are are different ways of achieving the same thing, two waves approximately 180 degrees apart at a listening position.

All arrays  have a maximum effect at one frequency with differing effects around that frequency.

As I said before I can't give you a meaningful comparison of the types because it depends more on the phase behavior of the boxes than the type of array.

If I had to make a comparison I believe endfire looses less ouput in the forward direction at the expense of needing more processing and space on the ground. Cardiod looses more output in the forward direction but is more compact and needs less processing.

But one again, time (delay) and distance (spacing) are the exact same thing.

I would suggest reading the first section of  Bob McCarthy's sound system design about the combing of signals and the two articles on Bennett Prescott's site and then trying to build a couple of these arrays. That should help you understand what is going on.

With that said, nothing you have said about the venue indicates to me it is a good candidate for needing this or that it would even be effective. You could end up perfectly cancelling the direct wave and still be slammed by the reflections.

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Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 04, 2016, 09:11:32 pm


How do i set up a standard cardioid then? I flip one box, flip it's polarity, and then i delay it how much? I tought i need to find the time that sub from the front boxes needs for reaching their back side/the front side of the flipped box.
I didn't think that this time was frequency dependant?


You REALLY REALLY need to read up on how this actually works and read what people are trying to tell you here.

If you don't get the time right-then how is the COMBINATION of time and distance going to give you a 180 out of polarity signal at the rear position?

You figure out what 1/4 wavelength of the freq of interest is.

Then you figure out what delay time is associated with that is.

Now you can vary these independently, but that is best done in models-not by simple math.

You will end up all sorts of "other things" happening at other positions.

That is what the mapping will tell you.

The above procedure works exactly the same way in both cardioid or endfire.

The difference is what cabinet the delay is applied to and whether or not the rear cabinet has reversed polarity.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 05, 2016, 04:36:55 am
Yes, i will need to find some good material to read this more detailed. I think i found MCCathy's book online, i also have a pdf of a Yamaha Sound_Reinforcement_Handbook so i will find something there.

Basicaly i didn't open this subject from a primary reason of finding what will work best in this situation but from a primary reason of learning more.
I do understand what happens with waves then they collide in phase, out of phase, and partialy out of phase but i obviously have holes in knowledge that don't allow me to fully visualise how a cardioid array works.

Ivan, don't get me wrong, i'm really thanksfull for the help but i'm constantly iritated by your posts from a simple reason. I don't need anyone to tell me what is going to be right because it's right. I need explanations to understand why something is right and why something is wrong. I'm 21 years old and i'm working in this club for a primary reason of learning. I do something, it does or does not work, i find all the elements i don't understand and then read to realise what i did wrong and why the solution didn't work the way i imagined. With sound there is a 100000 factors. All these arrays probably won't work even close to the way i imagine because i'm in a complex reflective room. But that's going to make me research a lot more speicific things. I will post a few pictures of the room during the next few days to give you a better idea of what this all looks like.

Now back to the subject.
There is one primary thing i believe i understood wrong because of the misinformations online. If i understand correct what you are trying to tell me now, the principal of sound cancelation in an endfire and a standard cardioid array is exactly the same. Just the endfire array with all boxes pointing forwards will have less energy to use for cancelation.

Because what i read online is different. The way i understood it is: A normal cardioid array has a box flipped backwards. That box is delayed using the time that sound coming from the front pointing boxes takes to get to their back side and that box is flipped in phase. An array like that will have most of the 20-80hz area effectively canceled out.
With an endfire array on the other hand, you have to pick the frequency you want to cancel out and position the back box according to that. The endfire array won't cancel out much other then a targeted frequency.

If what you are telling me is correct then what i just wrote is completly wrong. Both arrays work exactly the same way and both have a central cancelation frequency that i can change by moving the box that does cancelation. The only difference is that a standard cardioid array will have a box turned around and then will use the energy that comes out of the front of that box to cancel sound out. And the endfire array won't have a box turned around but will combine the energy coming from the back side of 2 boxes out of phase to cancel out.

Am i now closer to understanding this right?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 05, 2016, 08:52:10 am
For the most part-it does not matter which way the rear box is facing in a cardioid setup.


This is because at the freq we are talking about (below 100Hz) most boxes (especially front loaded ones) are omni directional.

Yes with the cardioid setup, you will effectively cancel out a wide range of the freq of interest.

HOWEVER-you also need to be conceded with what is happening out front-where the people are.

You can often end up with less energy at some freq out front with a cardioid setup than with a single cabinet.

So the sonic quality the audience hears is affected.

Does that matter? or is rear rejection the biggest concern?

I say that-because in some cases-the rear rejection IS the biggest concern.

Different people have different needs in different situations.

That is where the tuning comes into play.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 05, 2016, 09:44:08 am
For the most part-it does not matter which way the rear box is facing in a cardioid setup.


This is because at the freq we are talking about (below 100Hz) most boxes (especially front loaded ones) are omni directional.

Yes with the cardioid setup, you will effectively cancel out a wide range of the freq of interest.

HOWEVER-you also need to be conceded with what is happening out front-where the people are.

You can often end up with less energy at some freq out front with a cardioid setup than with a single cabinet.

So the sonic quality the audience hears is affected.

Does that matter? or is rear rejection the biggest concern?

I say that-because in some cases-the rear rejection IS the biggest concern.

Different people have different needs in different situations.

That is where the tuning comes into play.

I know, the only thing that changes when turning the box around is the amount of energy canceled in the back / amount of energy lost in the front

Is the backside cancelation the biggest concern?
I don't know. I will have to find out. The thing is, there is nothing making a particular problem when talking about the energy on stage.

But i think that what happens is...
Stage becomes one big speaker, all the sub that goes on the stage comes back into the room, late and out of phase, reducing the quallity of what i get in front. So i think i might get better overall sub quallity in the room by canceling out what goes on the stage. I think i will get better sub in front of the boxes by getting rid of what goes on the stage. If what i gain outside is lost by the fact that one or two boxes flipped around themselves are destroying sub quality in the front. Then i won't use that setup. That's what's probably going to happen.

An endfire array with all boxes pointing forwards will on the other hand give me some benefit in the back without loosing what i'm getting in the front. 

There is also another option similar to the endfire array.

It's called, the ICAD array.
Take a look at the bottom of this text under the sector "hybrid arrays":

http://www.fohonline.com/current-issue/74-tech-feature/8711-subwoofer-arrays-in-the-real-world.html
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Jay Barracato on February 05, 2016, 01:10:20 pm
I spotted your major misconception. A wave cancellation in one location dies not change the wave as it propagates to other locations. Causing a cancellation does not make the wave disappear, it makes a location with no amplitude.

Even if you create cancellation on stage those waves are going to reflect off the back wall and interact with FOH.

If you look back I have already mentioned the problems caused by reflections on small rooms twice

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Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 05, 2016, 07:35:54 pm

Stage becomes one big speaker, all the sub that goes on the stage comes back into the room, late and out of phase, reducing the quallity of what i get in front.
No.

What goes out into the room comes back in phase and out of phase-but at a different TIME.

So you will get additions and subtractions-at different freq at different locations.

Try this little test.

Put a 60Hz tone into the system-it does not need to be very loud-a comfortable level.

Now walk around the room and find the spots that are loud and those that are almost completely cancelled.

Now change the freq to something that is not a multiple of anything in the original.

Lets say 73Hz.  Now walk around again.  You will find that the hot spots and nulls have now moved.

This is classic room mode behavior.

Outside it is pretty easy to predict.  But inside, it is next to impossible using all sides and floor and ceiling.

Yes the idea of rejecting the energy to the rear is a good one.  But when you get close to a boundary-everything starts to change. 

The best thing is to play with it and see what you come up with.

Sometimes it is just better to pile them up and "go for it".

Don't get me wrong-I am not against directional bass.

I did a gig back in the fall that was outside and a lot of the acts on stage would have acoustic basses.  Typically those players HATE subs and DO NOT want to hear it on stage.

So I specifically designed a 3 pod cardioid (rejection WAS the main thing here).  There was a center pad of 2 subs and a left/ right pod of the same 2 subs.

I used odd spacing and delay to direct the cancellation to the sides of the pods at an angle.  Behind the left/right pods there was actually a good bit of energy.

Then the center was typical rear cancellation, but not using normal delay or spacing.  I modeled it to work with the left/right pods.

The result was a good solid sub level out front with nice even coverage and on stage it sounded as if the subs were not on.

I also did some level adjustments to smooth out the front coverage.

There were a variety of acts-from progressive fusion rock to traditional bluegrass.  So I needed a lot of energy out front when some acts were on stage.

I was VERY happy with the result.

But without the modeling-there is no way (short of MANY hours of guessing) that I would have been able to figure out where the cancellation lobes would be and how they would interact.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 05, 2016, 10:22:35 pm
I'm 21 years old
I realize you are young.

Please accept these couple of pieces of advice from somebody who has been doing this a "few" years/decades.

It is REAL easy to get obsessed over a small thing-and totally over the "big picture".  Like not being able to see the forest for the trees.

Also DO NOT assume that every thing you read that is being done on "the big shows" actually works as intended-without consequences.

There are A LOT of people in this industry who do things "different" just to appear as if they are "special".  There have been many things and articles published about things that simply do not work as described.

Just because it is published or on a spec sheet DOES NOT mean that it is correct.

You have QUESTION EVERYTHING and see if the idea/concept actually makes sense.

There is A LOT of BS out there.

One of the things I like about this forum is that if you are wrong-you WILL be corrected. 

Some people don't like that, but the more you know/understand about the TRUTH, the better equipped you will be read through the BS.

I will not mention any names, but some of the most respected people in our industry are simply WRONG on some of the things they do.  I have direct personal experience with this a few months ago.

But because they are respected they somehow get a "free pass".

But that does not make it right or mean it will work.

Some people like to "do something just to do something" to make it their own.  Like a dog peeing on a tire.

Understanding how and why things work can be VERY valuable. NOT just taking other people words for it.

Anybody can be an "expert"-at least until somebody smarter corrects them.

The only problem with understanding things, is that soon you will start to question more and more what people are doing.

Of course that also helps YOU do a better job.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 06, 2016, 06:25:25 am
Jay:
That's a good shot there. I red your reply last night and started thinking about it. It quiet logical actually.
When you throw 2 rocks in a pool, you can find spots where the 2 waves collide constructively, destructively, where you get flat spots etc... but past those areas. Both waves keep moving intact. They keep the same form that they had when the rocks created them and keep going untill they loose their energy by traveling too long or hitting boundaries.

Whitch means i saw this from a completly wrong angle. I tought that once waves collide in opposite phase, theirs energy is completly lost and they are stopped. But this doesn't actually make sense when i look at it now. Because it would mean that every time when waves in the room collide in phase, energy is magically created there...

This makes things a lot different and basically means that in this situation i don't get anything very usefull by canceling out the sub on stage.
The only thing i might get by canceling out certain spots in the club is stopping some wooden elements from vibrating and creating noise. But the biggest one is the roof itself which has been lowered with wood to reduce the amount of reverbation in the room. It resonates loud... but i don't know how would i stop sub from going there.


Ivan:
Yes, i understand, it will come back partialy in phase, partialy out of phase an will be late.
I have already done tests like this and tried flipping the phase of one side to change the  node/antinode pattern in the room and possibly getting something better.... didn't work. You change the pattern but it's still just as bad but in a different way.
Basicaly i'm trying to do anything i can to partialy fix this but it does not seem to be quiet possible withouth using bass traps to stop sub reflection. The situation does of course get slightly better by moving the boxes in a mono block because then at least they don't collide with each other. But that seems to be it. I will of course still try all these options to see what i get.


Don't get me wrong, i'm not trying to be a smartass here. I just want to learn as much as i can. By reading my wrong concepts you both explained me some important things. That's the way it goes. The thing is, when you write "you are wrong and that is not done that way" i will not say thanks because i have come across this attitude with many local sound engineers and it's quiet irritating and pointless. I will keep understanding it my way before someone explains the physics behind his claims. That's the only way a forum can be usefull. If someting is overly complicated for explanation you can allways suggest good literature. But seeing me as someone who refuses to understand just because i i won't accept something you said without being able to visualise it is pointless. We are not doing a live show and having a point of doing a job that is as good as it can be, we are on the forum just trying to learn things. I'm of course very happy to accept advices from people who have been doing this for a few decades :D

 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 06, 2016, 06:37:41 am
Just a few more questions:

1. If you take a subwoofer and put it in some kind of a concrete horn that won't allow sub to pass trough it's back side, that does not mean this will make the subwoofer more directional. The sub will again exit trough the front of the horn,then go around and back again. As soon as a low frequency wave is free in open air, it starts getting omnidirectional, there is no way to stop this by physicaly enclosing subwoofers right?

2. The mid-high boxes we have, the yamaha c215v, they are not "arrayable" / designed to be used in multiples per side because they have a wide coverage pattern and therefore start comb filtering when many of them are side by side.
We have 3 a side so you can hear this problem quiet a bit.
Is there any way to partialy stop this? Getting the boxes further apart, getting the boxes one on top of each other, putting some of them as a delay stack further in the club, what are my options?

3.
The thing i hate the most about this cw218v yamaha subs is how sloppy they sound. Slow drivers, shitty transient response. You can't feel sharp kick in your chest from them, it's just a mass of molded energy compared to a good sub. What can be done on this quiestion?
Maybe getting amps with better dampening factors and getting them as close as possible to subs to connect them with short neutrik cables?
I usually try boosting the 40-31.5 hz area to extend low end. Then keep them flat at 50 and 63hz because they have quiet decent sensitivity there and can overload the room. Then sometimes i try slightly boosting the 80-100hz area to make kick slightly sharper but the room is very ringy at 100hz so this can become a problem...
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 06, 2016, 10:14:44 am



I have already done tests like this and tried flipping the phase of one side
You need to be VERY VERY careful when talking about phase and polarity.

In this post you are mixing the two, yet they are COMPLETELY different things.

Phase is a TIME issue.  Polarity is NOT.

Yes it does make a difference.  But many people in our industry are ignorant of that fact.

They brush it off-but it IS important to know the difference and where it applies.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 06, 2016, 10:21:06 am
Just a few more questions:

1. If you take a subwoofer and put it in some kind of a concrete horn that won't allow sub to pass trough it's back side, that does not mean this will make the subwoofer more directional.

3.
The thing i hate the most about this cw218v yamaha subs is how sloppy they sound. Slow drivers, shitty transient response.
Maybe getting amps with better dampening factors and getting them as close as possible to subs to connect them with short neutrik cables?

Yes a large concrete horn will be able to make the bass directional.

HOWEVER-due to the wavelengths-it is going to be larger than the space you are in.

A VERY IMPORTANT fact to realize is that sound wave have size-based on freq.  The lower the freq-the longer they are.

So what it takes to control them get larger and larger as you go lower and lower.

For the most part-don't waste your time/money on getting amps with larger damping factor.

There are many posts on here talking about that.

Use short cables of a large ga is your best best.

But part of the "sloppy sound" is also due to the cabinet/loudspeaker design.  It is all a trade off of one thing for another.

You can only "fix" something so much with outside parts. 

Sooner or later you need to look at the real issue and what you are trying to achieve.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 06, 2016, 10:40:17 am
You are right but most sound engineers call the polarity flip switch on a channel on a mixing board: "A phase flip switch". So this wrong terminology got in my head. I meant polarity.

I understand. So tehnicaly if i wanted to make a subwoofer directional down to 20hz i would need a 17 meters long concrete horn that wont let the sound penetrate to it's back. Then the wave would exit it only once it's fully formed.
Then basicaly what is the cause of sub omnidirectionality? A driver is pushing air and the pressurised area starts to go not only in front of the box with drivers but also on the sides and back of the box.
Why does this happen from the aspects of physics. Where can i read about this?

Also why is it a rule with horn loaded subwoofers, that if you wan't a subwoofer to effectively reproduce sound down to XY hertz, it's horn need's to be long at least 1/4 of the wavelenght of the XY frequency.
Why is it 1/4, why not the entire wavelenght?

And yes, i understand that i can't do much about the fact that those yamaha subs are simply not very good. But at least i will try with shorter cables.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 06, 2016, 12:24:02 pm
You are right but most sound engineers call the polarity flip switch on a channel on a mixing board: "A phase flip switch". So this wrong terminology got in my head. I meant polarity.

I understand. So tehnicaly if i wanted to make a subwoofer directional down to 20hz i would need a 17 meters long concrete horn that wont let the sound penetrate to it's back. Then the wave would exit it only once it's fully formed.
Then basicaly what is the cause of sub omnidirectionality? A driver is pushing air and the pressurised area starts to go not only in front of the box with drivers but also on the sides and back of the box.
Why does this happen from the aspects of physics. Where can i read about this?

Also why is it a rule with horn loaded subwoofers, that if you wan't a subwoofer to effectively reproduce sound down to XY hertz, it's horn need's to be long at least 1/4 of the wavelenght of the XY frequency.
Why is it 1/4, why not the entire wavelenght?

And yes, i understand that i can't do much about the fact that those yamaha subs are simply not very good. But at least i will try with shorter cables.
There are 2 aspects to horns and people often get them confused.  Like polarity and phase.

BTW the console manufacturers don't help any when they put a "phase" symbol on the polarity button.

The 2 aspects are pattern control and horn gain.

You can have one without having the other.

The pattern control (which does not stop the sound-just reduces the level at the edges and beyond) is based on the wavelength-the pattern of the coverage and the physical size.

As the pattern get narrower the size MUST get larger.  As the freq goes lower the size MUST get larger.

The other aspect is horn loading or acoustic gain.  It is a common misconception that putting a loudspeaker on horn will make it louder.  Well it will-but ONLY over a limited range of freq.  A simple horn is not a broad band device.

Once the freq get to high for the physical size entrance to the horn-no more gain can be had (except from the narrowing of the coverage pattern)

It is for this reason that smaller HF drivers can take advantage of horn gain to a higher freq than larger exit drivers.

On the bottom end you have things like expansion rates and the physical size of the horn to limit how much gain can be had

Lower freq need slower expansion rates than higher freq.

The reason that most subs are omni directional (yes there are exceptions) is simply due to the fact that the size of the wavelength is large as compared to the radiating source.

Think of it like this.  Go to the ocean and find a pier or piling sticking up.

Look at the waves-there are basically 2 sizes the large waves that you surf on and the little waves that are caused by the wind.

Now look on the backside of the piling.  Notice how there is a smooth area of the smaller waves?  This is because the piling is large as compared to the size of the small waves.

ALSO notice that the large wave size is completely unaffected by the piling.

This is because the size of the wave is LARGE as compared to the size of the piling.

If you want to control large waves (low freq) you MUST use large things.

Just like small acoustic materials can only control the smaller high freq0they do nothing for the larger low freq.

When you start to think of things in terms of physical size vs freq, you start to get a understanding.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Art Welter on February 06, 2016, 12:46:02 pm
Just a few more questions:

1.  As soon as a low frequency wave is free in open air, it starts getting omnidirectional, there is no way to stop this by physicaly enclosing subwoofers right?

2. The mid-high boxes we have, the yamaha c215v, they are not "arrayable" ..We have 3 a side so you can hear this problem quiet a bit.
Is there any way to partialy stop this? Getting the boxes further apart, getting the boxes one on top of each other, putting some of them as a delay stack further in the club, what are my options?

3. The thing i hate the most about this cw218v yamaha subs is how sloppy they sound. Slow drivers, shitty transient response. You can't feel sharp kick in your chest from them, it's just a mass of molded energy compared to a good sub. What can be done on this quiestion?
Maybe getting amps with better dampening factors and getting them as close as possible to subs to connect them with short neutrik cables?
I usually try boosting the 40-31.5 hz area to extend low end. Then keep them flat at 50 and 63hz because they have quiet decent sensitivity there and can overload the room. Then sometimes i try slightly boosting the 80-100hz area to make kick slightly sharper but the room is very ringy at 100hz so this can become a problem...
1)When the sound wave is large compared to the exit (or baffle) size, it diffracts around the exit, similar to the difference in pattern between a garden hose, and a garden hose with a small exit (like your thumb pressing over the exit), the small exit sprays wide. Bass horns start being effective in output down with 1/4 wavelength, so are generally not made longer. To be effective in controlling directionality the diameter would need to approach the wavelength, obviously not possible in a typical venue.
2)Vertical stacking with the HF horns together will reduce horizontal lobing, and (in general) reduce vertical dispersion, though with a pair of 2x15" it may not be possible to get the HF horns high enough to be above head height. Delayed speakers may be a better option, but introduce off axis timing and phasing problems due to path length differences at various off-axis time of flight differences.
3) Much of the "sloppiness" of the subs is likely directly due to your EQ approach. BR (bass reflex) enclosures rely on the phase inverted port output around Fb (box tuning frequency) to reinforce the front output. At Fb, the driver's excursion is at minimum, and port output (Helmholtz resonance, like blowing across a jug mouth) is at maximum. Below Fb, excursion (and distortion) increases rapidly, and port output also rapidly drops. You are boosting below Fb- which will waste power, and make the rest of the output sound sloppy, because the cone is "flopping around", not doing useful work. Put a dot (white out, silver Sharpie) on the cone, run a sine wave sweep (use about 10 volts) from 100 Hz down, you will see the cone excursion start to increase, then it will decrease to it's minimum at Fb, then rapidly increase again. Once you determine Fb (probably around 45 Hz) set the HP on your DSP to a LR 24 filter a few Hz below Fb to keep the excursion under control. If excursion exceeds Xmax (one way linear travel) the driver's output will start sounding like crap. Cheap(er) speakers generally have only half (or less) Xmax than state of the art speakers- doubling Xmax (and power) allows 6 dB more clean output.

Second problem is alignment- your top cabinets are also BR, and have a phase inverted output at the lower end of their range, but the sub's upper range phase is not- to align the phase of the two in the crossover region may require delaying either the sub or tops slightly. Since your crossover is likely in the 80-100 Hz range where "punch", and "tight" (as opposed to "sloppy" response lives, proper phase alignment is crucial in that region.

That said, the third problem of room modes and L/R distance relationships will dominate LF response, a perfectly aligned system will still not "win" over a bad room. Reduction of the most offensive frequencies (after system alignment and properly setting HP filters) will "clean up" the sound a bit, but only provides a compromise,  the "greatest good" for the most will still result in some areas that are no good.

Art
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 07, 2016, 06:34:05 am
Ivan:

So about horns. I'm not exactly understanding what you are trying to say.
Small drivers like compression drivers/tweeter usually have a horn in front of them
and the reason for that horn is pattern controll right? It controls how a tweeter covers the area in front of it. Under which angle.

But on the other hand, that tweeter won't get much when talking about horn gain?
Once you remove the horn from it, it doesn't really get much quieter right?

The way i see it... those waves are too small to make a horn usefull for them when talking about gain. The membrane is moving so fast that the air in front of it does not have the time to escape, a tweeter effectively compresses that air even if it's completly free right?

On the other hand, that big 18 is moving slow compared to the tweeter membrane. So if it's free with no box, the air will simply move away from  the membrane and it won't effectivley compress it. When you then put that driver in a horn, the horn keeps the air in place allowing the driver to compress it.

Am i seeing this right?

If i am then, the way i understand it is, if the horn is too short the air will start beeing free and exiting the horn while the driver is still pushing it. Which will drasticaly drop the effectivenes of the horn. That's all understandable but why then is there that rule that if you want a horn loaded subwoofer to be effective at let's say 40hz. The horn needs to be 1/4 of the 40hz wavelenght long?
Why wouldn't it need to be as long as the entire wavelenght of 40hz? If it's only 1/4 the air will still start escaping the horn when the driver is still pushing it. That will drop the pressure inside the horn and make the driver a lot less effective?

The other thing is, how can a bass reflexx box go lower then a horn while staying relativley small. The bass reflex box also wouldn't be able to keep the air inside during the entire cycle that a driver does.
This is obviously because a bass reflex box works on a totaly different principal of a horn. Where can i read more about this?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 07, 2016, 06:53:56 am
Art:

1) I will go read about wave diffraction now, i want to know how it works.
Talking about horns, the same thing that i just asked Ivan.
So i understand that in order to control directionality a horn needs to be as long as the wavelenght which is not possible.
But why does it only need to be 1/4 wavelenght to be effective for horn gain? Shouldn't it be keeping air in place during the entire cycle of a driver?
And why does if need to start narrow and then keeps getting wider. I understand that this is because it slowly changes the impedance of air but i don't understand how it works. Why wouldn't it work if it was just a straight tunnel in front of the driver, the same size during the entire path of the horn.

2.
Those boxes wouldn't be on the floor. The first one would allredy have the horn/tweeter above heads of people. The second box on top of it would then get very high and maybe improve the throw of the PA. It would maybee loose less SPL over distance which i could use.
But you are saying that if i stack them on top of each other i would get less comb filtering/lobing horizontaly?
Verticaly it's not that important. People don't walk up and down in the room, they walk from left to the right. But what did you mean by reducing vertical dispersion?

3.
Very interesting. I'm doing a big mistake then, probably because i mentaly trick myself into believing these subs are actually giving me decent pressure at 35-40hz.
The thing is, when i take the parameter eq on the behringer x32 i use for control, and boost the 40hz area to make their sub extension go lower. What that probably does if not actually giving me anything much usefull at 35-40hz but does boost the 50hz area because i use wide Q when i do the boost. And then it tricks me into thinking they are giving me pressure at 40hz. I will definitly test this the way you told me. If i lowcut them properly, they will be under less load and start working more precise. Basicaly i shouldn't make them to any work under tuning frequency right?

Yes the crossover is around 100hz and yes i have been thinking about this buy tought that the entire PA is a yamaha club series and should be designed to work well with a top box on a subwoofer with no delay, i tought it's logical they both push frequencies aroung 100hz in phase when they are physicaly aligned. That's obviously wrong so i will try delaying them.

Thanks!

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 07, 2016, 09:10:52 am
Art:
 
Talking about horns, the same thing that i just asked Ivan.
So i understand that in order to control directionality a horn needs to be as long as the wavelenght which is not possible.

No.

The length of the horn has almost nothing to do with the freq for directivity.

Here is the basic formula for figuring out pattern control.

Of course the sound does not stop at those angles-but is generally considered to be 6dB down.

Freq of control=1,000,000/(size of horn exit in inches x rated pattern in degrees)

Of course the length will be what it needs to be.

But if you run the numbers you will see that a wider coverage horn will be smaller (for a given freq) than a narrow coverage horn.

Or looking at it a different way- for a given freq a narrower horn will be deeper than a wider horn.

The 1/4 wavelength has to do with HORN LOADING-NOT pattern control

Those are different things that require completely different approaches in the design.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 07, 2016, 09:37:01 am
No.

The length of the horn has almost nothing to do with the freq for directivity.

Here is the basic formula for figuring out pattern control.

Of course the sound does not stop at those angles-but is generally considered to be 6dB down.

Freq of control=1,000,000/(size of horn exit in inches x rated pattern in degrees)

Of course the length will be what it needs to be.

But if you run the numbers you will see that a wider coverage horn will be smaller (for a given freq) than a narrow coverage horn.

Or looking at it a different way- for a given freq a narrower horn will be deeper than a wider horn.

The 1/4 wavelength has to do with HORN LOADING-NOT pattern control

Those are different things that require completely different approaches in the design.

Okay so if i wanted to make a 20hz wave directional i wouldn't need a 17 meters long horn. I would need to take that formula and see how big the horn will have to be?

And yeah, time to go read about horn loading. I understand that it has nothing to do with pattern control because the point in this case is increasing efficiency, not directing sound.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 07, 2016, 10:19:39 am
Okay so if i wanted to make a 20hz wave directional i wouldn't need a 17 meters long horn. I would need to take that formula and see how big the horn will have to be?


I gave you that formula in my last post.

The formula describes the size of the mouth for normal pattern control

Then all you have to do is to determine what length at the specific ANGLE of the direction that it needs to be.

A wide horn will not be as deep as a narrow horn.

But FIRST-YOU have to say how much directivity or what angle you are interested in.

Is it 40* or 90* or 180* etc.

You could "argue" that 300* is more directional than 360*.

So defining the parameter you want is the first step in ANY audio design.

If you don't do that-it is like saying "I want a powerful amp".

So how do YOU define powerful?

Is it 1000 watts, 10,000 watts, or 20 watts.

It all HAS to be based or referenced to something else.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 07, 2016, 10:23:31 am


I understand. So tehnicaly if i wanted to make a subwoofer directional down to 20hz i would need a 17 meters long concrete horn that wont let the sound penetrate to it's back. Then the wave would exit it only once it's fully formed.

The "fully formed" wavelength is another misconception that people often have.

I heard it said that you have to have a large room to get deep bass.

Really?  Then how do you get deep bass in a car (that is a pretty small room) or when you use headphones (that is a VERY small room)

People also say that a small microphone can't pick up bass?  Why?  But it seems strange that the mics that typically go the lowest have the smallest diaphragms.

YES-size matters-but only in certain areas.

Proper understanding is what really matters.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 07, 2016, 10:47:51 am
Yes, i understand.I just wanted to check if i got it right.

I also heard the same claim. Did see no logics behind it. You can go as low as yours PA can go no matter what the size od the room is. I heard it, i felt it.

But there is a very interesting effect i don't understand. It's kind of like, no matter how good the soundsystem is, if you come to an electronic party in an average club with 4 good double 18's. Those subs can be the best subs in the world, go down to 20hz, push painfull amounts of SPL, have amazing transient response, the room can be treated, it's going to sound awesome.

But then again, that same sound, those same boxes, that exact same song at the exact same SPL. But this time in a football stadium with not 4 of those double 18's but a 140 of them. Is going to give a completly new level of a "WOW" effect.

Basically you are reaching the exact same thing but with so much more power.
I can't understand which parameter there is that makes that wow efect so big. Maybe it's the combination of the football stadium resonating extremly low + the beautifull reverb it gives?

I live in Croatia, i remember ultra europe 2014 when the RCF team from Italy brought 48 2X21 RCF TT56-A boxes. Yes, EDM music is low quality music in electronic world. But that was the best sub i have ever heard and felt in my life. It felt like earth was going to swallow the football stadium.

Last year they used an l'acoustics system which was a total mistake for that type of music. They pushed around 60 of those SB28 subs. It sounded like you are trying to run an 800ppl club topped up with a single 18 cab.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 07, 2016, 07:48:16 pm
It is real easy to get "hung up" on particular pieces of gear.

People do it all the time.

But in MANY/MOST cases-it is how the particular is used that makes a HUGE difference.

You can have the identical system, but tuned by different people and it can sound very different.

Also different people "go for different things" when tuning.

Some is scientific-some is personal preference.

What works well for one type of music does not always work well for a different type of music.

Sometimes you have to ask yourself-what is the "purpose" of the sound system?

Is it to accurately reproduce what is going into it from the artist?

OR is it to have a sound of its own and becomes an "extension" of the incoming signal?

Unless you/yourself actually setup the system in question, it is hard to say that a particular piece of gear was the problem.

Sometimes it is REAL evident. Other times-it is not so easy.

And always remember that people will blame the gear LONG before they will acknowledge their own lack of skill/knowledge.

BELIEVE ME-I have run into MANY people over the years who could not mix a cake-yet they always blame the gear for the bad sound.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 08, 2016, 05:12:13 am
Of course. I try my best to deliver not what i want but what the music requires.

But the specific subject of sub sloppines wasn't about what i want it was about the fact i want to get something out of the system but i maybee don't know how.
What i really want is to learn how to get as much precision from these yamaha subs as it is possible. Yes they are not good boxes, they are sloppy. But part of the problem might be my approach.
I will try what Art suggested.

Also, could you reflect on the club/stadium situation a wrote about above?
I'm really interested in what the difference parameter is.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Scott Holtzman on February 08, 2016, 05:48:32 am
Of course. I try my best to deliver not what i want but what the music requires.

But the specific subject of sub sloppines wasn't about what i want it was about the fact i want to get something out of the system but i maybee don't know how.
What i really want is to learn how to get as much precision from these yamaha subs as it is possible. Yes they are not good boxes, they are sloppy. But part of the problem might be my approach.
I will try what Art suggested.

Also, could you reflect on the club/stadium situation a wrote about above?
I'm really interested in what the difference parameter is.

75 posts and you are looking for the "sound better" knob?  Or a magic placement that will make your mediocre subs sound like 100k worth of Danley's finest? 

It's a process, the process yields incremental gains and an occasional step backwards.  Unless something is totally messed up don't expect those increments to be very large.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 08, 2016, 06:08:47 am
75 posts and you are looking for the "sound better" knob?  Or a magic placement that will make your mediocre subs sound like 100k worth of Danley's finest? 

It's a process, the process yields incremental gains and an occasional step backwards.  Unless something is totally messed up don't expect those increments to be very large.

Nope, i understand it's trial and error. That's what i do every single party.
But we hit a specific subject on the EQ approach. I might be seeing things quiet wrong. Art explained it quiet well.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Scott Holtzman on February 08, 2016, 06:26:14 am
Nope, i understand it's trial and error. That's what i do every single party.
But we hit a specific subject on the EQ approach. I might be seeing things quiet wrong. Art explained it quiet well.

Yep, sounded like you were expecting a dramatic improvement.  Quite a bit of good data was shared in all these exchanges.  While I wasn't participating I was following along as were 100's if not 1000's of others.

Great learning experience for all.  Even the experts, by explaining the information they "sharpen their saw" so to speak.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 08, 2016, 07:03:13 am
Yep, sounded like you were expecting a dramatic improvement.  Quite a bit of good data was shared in all these exchanges.  While I wasn't participating I was following along as were 100's if not 1000's of others.

Great learning experience for all.  Even the experts, by explaining the information they "sharpen their saw" so to speak.

Not really, drivers in those boxes are cheap emminence crap. You can't expect much out of them. But even if i don't get an improvement, the point is learning. I learned a lot during this subject.
And since the next party is tommorow and then a bigger one in 10 days. I still have to try out these setups and advices to give some real life feedback.

You never know enough when it's about sound. I think many sound engineers, at least local ones. Don't see understanding wave physics as that important. They think, im a FOH engineer, not an expert in electro acoustics.
But that's quiet wrong. You can't visualise how many of these things work withouth a good understanding of deeper,more basic things. That means you will never get to some conclusions, soultions and steps forward. 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 08, 2016, 07:50:57 am
Nope, i understand it's trial and error. That's what i do every single party.

In the early days it was a lot of "trial and error"

Believe me-I did my part-and learned quite a bit from it.

But today-you can get past a lot of the "trial" part.

We did not have the internet and the audio classes like we do today.  It is MUCH easier to share information than in the past.

Researching and understanding can go a LONG way.

HOWEVER-there is A LOT of misinformation out there.  So understanding what is actually happening will help you figure out what is good or bad.

On these forums at least-if any information is presented that is false-it WILL be corrected.  There are many knowledgeable folks on here.    Unlike other forums that are full of "feel goods" and people passing on myths.

Like damping factor factor.  Don't waste your time looking for an amp that has a higher damping factor to clean up your "sloppy" subs.

You could buy the most expensive amp out there with the highest damping factor-yet I highly doubt you could pick it out in a blind test-as long as everything was running in the linear range.

Just make sure you use large wire and keep it short.

But even then-if you ran longer lengths-it is not going to make as much of a difference as getting speakers that can do the job you need done.

I have run shows on very long speaker cables and nobody complained about the "sloppiness".

What you are doing is trying to take a small engine and put a bunch of "fixes" on it-instead of getting a good engine.

Yes you can make some small improvements-but nothing really worth while.


Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 08, 2016, 08:31:56 am
Yes i will agree. That's why i'm here. To learn faster and get around some trial and error. And yes, i'm very suprised by this forum. I got used to getting tons of misinformations by people having less experience then you yourself most of the time i went on a forum to get advices. Here it's really different. I got so much great info in this subject.

Yes i'm very aware of that. When i red on what principal the damping factor works it kind of made sense but thain again... nothing is going to make a big cheap slow heavey sloppy driver move precise and fast.
Cosidering the price of these yamaha boxes they work quiet well. Subs are about a 1000 dollars each brand new. Those emminence drivers inside are some of the cheapest 18's money can buy. What can you expect from them...

Still, i will try all of what we talked about because i want to hear is there going to be a difference that i can hear. Many of those small things can make a noticable difference in the whole picture.

Last time we had a big techno name in the club we rented what you see in the picture (just withouth tops, we used our yamaha mid-hi boxes)

http://www.uesmag.com/wp-content/uploads/2014/10/boca_zvuk.jpg

These boxes were cut, hog scoops: 30-65hz, kickers 65-150hz i think with a slope of 24dB/octave.
Pushed them with MC2 amps.

With them i could reach some actual sub, not molded energy. Amazing transient response, fantasticaly fast drivers. I think some B&C 18's.
I don't remember when i heard something so defined and sharp. They also had more then enough power to do whatever i wanted with them. And to cause 40hz needle feedback from the vinyl players on stage :D
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 08, 2016, 01:19:11 pm

Last time we had a big techno name in the club we rented what you see in the picture (just withouth tops, we used our yamaha mid-hi boxes)

http://www.uesmag.com/wp-content/uploads/2014/10/boca_zvuk.jpg

These boxes were cut, hog scoops: 30-65hz, kickers 65-150hz i think with a slope of 24dB/octave.
Pushed them with MC2 amps.

With them i could reach some actual sub, not molded energy. Amazing transient response, fantasticaly fast drivers. I think some B&C 18's.

In many cases it is NOT the driver-but rather the cabinet and how the driver is loaded that makes the difference.

Take the same driver-put it in a different type of cabinet and you can get different results.

Typically bass horns have less distortion than front loaded boxes.  This is because of 2 reasons.  One is that the cone is not moving as far.  With any loudspeaker, the further the cone moves-the more distortion it has.

Second is that the higher freq (the distortion components) do not "make it around the bends" in the horn-so they are physically attenuated or not as noticeable.

In a horn, the driver/cabinet combination has to be closely matched to get the best response.

With a ported box, the cabinet more or less determines the tuning/response.  You can swap drivers around in ported cabinets much easier than in horns.

In most cases putting "better" driver in a ported cabinet will result in better performance.

But horns are different.  Often putting "better" driver in a cabinet designed for a different type of driver will result in LOWER performance.

But good drivers in cabinets designed for their parameters will result in better performance.

Sometimes the "fast sound" is associated with lower distortion.  But some people like the extra distortion that comes from front loaded cabinets.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Stephen Kirby on February 08, 2016, 02:40:22 pm
I see another term used here a bunch, that is a driver or sub system is "fast" or "slow".  As was explained, a bass reflex cabinet is a resonant cavity.  At some frequency the combination of the compliance of the air in the cabinet and the compliance of forcing air through the port will resonate.  Which creates output at the port instead of physically coming from the surface of the driver.  This resonance can be adjusted to be very severe or more moderate.  More severe resonance can produce more output but mostly at that particular frequency.  The old "one note wonders" that boom at one frequency and sound loud but any other note drops off appreciably.  Like blowing over a bottle, that sound doesn't happen instantly.  And as also pointed out, below that point, at high levels the cone is flapping around uncontrolled producing lots of distortion.

The net is that the more you try to get out of a driver by tuning a cabinet low and with a high Q, and then try to eq more low end out of it, the "slower" or more boomy it will sound.

Also, pretty much every low tone has higher frequency components.  When these get smeared in time compared to the fundamental the tone becomes muddled and incoherent.  Audiophiles refer to this as "pace".  Music loses it's timing and groove as the low frequency cues we rely on are not in time with the rest of the sound.

As was pointed out, there are a number of phase inversions going on in a system with a ported cabinet sitting on top of a ported sub.  The crossover also creates some.  If you had Smaart or something you would see the phase slope going one direction and then the polarity flipping back until the next point.  Probably several times in the region where both sub and top are playing.  At every point along this, the combining sounds are going to have cancelations and additions at some point in the room.  These sounds in the 50-150Hz range have to be coherent with the other upper harmonics of the sound as well as any 30-60Hz fundamentals (if you're doing electronic music where these are artificially generated) for the timing of the sound to appear "fast" or together.  If they are smeared in time or canceling out parts of the sound, the result will sound "slow".

Some of this can be mitigated by system alignment.  But you cannot get 30Hz EDM out of your boxes at any appreciable levels.  If you redirect your efforts to optimizing the setup within it's capabilities, you may find that the "slowness" is reduced and even though their may not be the extreme lows the music has more visceral punch and is more enjoyable for the audience.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 09, 2016, 04:56:00 am
Another two really usefull posts.

Let me check if im getting this right. I knew that a horn loaded and a bass reflex box have a completly different principal of working but it think i get it now.

The biggest problem with big slow 18 inch sub drivers is that they move slow and air it not thick enough to let that slow driver push it with high efficency. If the 18 inch driver worked under water, it would have a much easier task of pushing the medium around it. However we are not fish so it would be great if we could make the air thicker for that 18 inch driver...

And that's just about what a horn does right? The initial opening (the throat) of the horn is very small in the place where it connects to the chamber that the driver is in. When it starts moving air, that opening resist that amount of air from going trough it, it's like when you are trying to blow very fast trough a small hole. It's hard.
So pressure and air thickness inside the chamber where the driver is rises when the driver is moving and then that driver starts turning mechanical energy into acoustical energy much easier. The air has no where to escape so fast because the small opening of the horn is resisting.

What i don't get here is... the horn needs to get wider when you get closer to it's mouth, that's how it slowly adjust impedance of air to the outside air impedance. But why is this needed. Wouldn't the driver work efficient if the mouth and the throat diameter were the same size? Or would this be a problem because then the horn wouldn't fit as much air so it would start escaping it much sooner and the pressure inside would drop?


Talking about bass reflex box. It's principal is completly different. The box does hold air around the drivers but that only rises efficiency a lot when the antinode, the pressurised area inside the box, is in the same place as the port opening. And that's only at the tunning frequency. Would this be the correct vision of things?

I see why a horn has many benefits over a bass reflex box. The driver will automaticaly sound more precise when working under higher pressure/air impedance because it will move less.
But of course the drivers parameters have to be mached to the horn parameters. And yes... if we would want a horn going lower then 30hz we would need something bigger then a standard HOG folded horn. Which then couldn't go trough the door of a standard club and would be very impractical.

Now can you just correct me at all the things i just wrote wrong? That way i will understand my own misinformations the best.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 09, 2016, 05:11:10 am
Stephen:

So the thing is, every system where there is a bass reflex box on top of another bass relfex box will not be perfectly in phase in the 50-150hz area where the crossover comes in.

If i delay one of the boxes what can i get? I can't get perfect summation but can get some frequencies in phase right?
At what price?

If i try getting them perfectly in phase at 100hz that might give me some more sharpness that but will cost me something?

Also. You are basicaly saying the more low end i try to EQ out of the system the slower it will sound. Especially if i try pushing below tunning frequency which i shouldn't do? 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 09, 2016, 07:47:54 am
You need to stop using the terms "fast and slow".

I know they are "popular" but have no real meaning.

The rate at which a cone moves is based upon the freq that is applied.

A horn is an impedance coupling device between the air and the driver.

With a good coupling, then it takes less driver excursion to reach a certain SPL.

But just like an electrical transformer that can change voltage, there are tradeoffs.

Yes you can get a horn that is flat to around 20Hz and loud, through a normal door way.  It just has to be designed that way.

There are some advantages to a bass reflex cabinet as well.

It all depends on what the end result is and what is most important.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim McCulloch on February 10, 2016, 12:58:12 am
Another two really usefull posts.

Let me check if im getting this right. I knew that a horn loaded and a bass reflex box have a completly different principal of working but it think i get it now.

The biggest problem with big slow 18 inch sub drivers is that they move slow and air it not thick enough to let that slow driver push it with high efficency. If the 18 inch driver worked under water, it would have a much easier task of pushing the medium around it. However we are not fish so it would be great if we could make the air thicker for that 18 inch driver...

And that's just about what a horn does right? The initial opening (the throat) of the horn is very small in the place where it connects to the chamber that the driver is in. When it starts moving air, that opening resist that amount of air from going trough it, it's like when you are trying to blow very fast trough a small hole. It's hard.
So pressure and air thickness inside the chamber where the driver is rises when the driver is moving and then that driver starts turning mechanical energy into acoustical energy much easier. The air has no where to escape so fast because the small opening of the horn is resisting.

What i don't get here is... the horn needs to get wider when you get closer to it's mouth, that's how it slowly adjust impedance of air to the outside air impedance. But why is this needed. Wouldn't the driver work efficient if the mouth and the throat diameter were the same size? Or would this be a problem because then the horn wouldn't fit as much air so it would start escaping it much sooner and the pressure inside would drop?


Talking about bass reflex box. It's principal is completly different. The box does hold air around the drivers but that only rises efficiency a lot when the antinode, the pressurised area inside the box, is in the same place as the port opening. And that's only at the tunning frequency. Would this be the correct vision of things?

I see why a horn has many benefits over a bass reflex box. The driver will automaticaly sound more precise when working under higher pressure/air impedance because it will move less.
But of course the drivers parameters have to be mached to the horn parameters. And yes... if we would want a horn going lower then 30hz we would need something bigger then a standard HOG folded horn. Which then couldn't go trough the door of a standard club and would be very impractical.

Now can you just correct me at all the things i just wrote wrong? That way i will understand my own misinformations the best.


A smaller, lighter piston mass can be accelerated faster than a more massive piston when the same motive force is applied.  As with cars, greater mass requires greater force to achieve the same results.  As Ivan alludes to, though, it's a matter of what frequency is being reproduced; your concern seems to be how soon (relatively speaking) the transducer produces the onset of the waveform from the time voltage is applied.

In that regard, filters will have a far greater impact.  A HPF, 48dB/oct at 20Hz, for example, is going to introduce more group delay than the same filter at 80Hz, or 12dB/oct at 20Hz.  The more times you have to make a trip around the Phase Wheel, or the slower (lower frequency) your trips, the greater the delay.

As for why a horn acts as a transformer, you have to think of air in a planar sense.  Air in not "pumped" out of a horn.  Sound propagates when air molecules bump into each other, so the smaller throat expands into the mouth, and the area of the transducer becomes "virtually" bigger.  You now have a much larger radiating area than you have with just the transducer's piston.  Also, because there is no "pumping" of air, the air in the horn, from transducer entry to mouth, is essentially captive, and it has it's own mass and compliance (just like the air on the back side of the transducer).  To achieve the same SPL with a raw transducer would require much greater drive voltage and tolerance of greater distortion as well.

If you have some basic electronics theory in your background you might find it useful to look at various types of subwoofers as their schematic equivalents.  Cabinet design (bass reflex, band pass, horns, tapped horns) all have acoustic behaviors that can be modeled as electronic circuits.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 10, 2016, 07:34:11 am

A smaller, lighter piston mass can be accelerated faster than a more massive piston when the same motive force is applied.  As with cars, greater mass requires greater force to achieve the same results.  As Ivan alludes to, though, it's a matter of what frequency is being reproduced; your concern seems to be how soon (relatively speaking) the transducer produces the onset of the waveform from the time voltage is applied.


People also associate "speed" with higher freq reproduction.

The issue starts when you look at drivers.  Typically larger heavier drivers have larger voice coils (and magnets).

The larger voice coil is going to have a greater self inductance.  This means it has a "natural" high freq rolloff (the inductance is effectively in series-just like a coil in a low pass crossover).

You don't see heavy drivers with small voice coils (they would not work well due to the lack of driving force)

And it is very rare to find a light cone with a large voice coil.  But some exist.  And of those-the xmax is very small-limiting them to non sub freq.

Everything is a trade off-so you have to figure what is best for a particular situation or usage.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 10, 2016, 10:09:51 am
When i say a fast driver i don't mean fast in terms of speed that the driver is moving at. I mean, how fast will a driver accelerate to a certain movement and how fast will it stop once it stops getting signal due to it's dullness which is effected by the materials of which the membrane and suspension/surround are made. And of course it will depend on the box that the driver is in.

Yesterday we had a party. The last DJ was playing dnb, a bit of noisia a bit of pendulum, it was a slightly more commercial party this time, usually we do only underground stuff.
I tried the different EQ approach we talked about. Yes, if i low cut them at about 37-38hz there is not much loss in sub frequencies and there is a slight gain in precision but they still will sound very floppy and wont hit you in the chest nice and sharp.

I also tried delaying the tops or the subs to make them perfectly in phase just like art suggested but i couldn't get much. If i play a 100hz sinewave tough both the subs and the tops at the same level and then try delaying one of them... the results you get are not usable. You get a 1-2dB bump in one spot, but a loss in another. There was no combination that gives you some gain at around the crossover frequency at any or most spots in the club. The room is simply fucking things up way to much to hear these delicate differences.

I also tried delaying one side of the PA to move nodal/antinodal areas in sub frequencies. Yes i could affect the spots where subs summed or canceled out on a certain frequency. But again, not much can be gained. I create a nodal cancelation area close to a wooden resonating part of the club, great, it stops resonating, but now i have cancelation in front of the stage. More damage then good done...

And yeah, none of the things i try with this pa will give it a significant amount of sharpness. Most of theese kick transients in music like this look quiet much like...
there is a loud harmonic between 100-200hz that you hear like a snap and slightly feel in your chest. Then there is a subharmonic around 40-50hz that follows that upper kick tone.
That subharmonic has to punch you fast, it has to be a "bum" not a "wooofff..." the way i see it is, once that subharmonic hits the amp, the driver needs to accelerate from standing still to that 40hz hit as fast as possible and then stop as fast as possible once it stops getting signal. These emminence drivers in the combination of the boxes they are in are simply to dull for that.
It will be to slow in accelerating to reaching that 40hz vibration, which will mean it will basicaly be late to follow the upper ~150hz kick, and then when the transient ends the cone will keep flopping around for too long insted of stopping fast. No matter what i do this is the way these boxes behave.

The more load you give them the less precise they become. If it's only a fast 40-50hz hit it might be somewhat decent, if it comes on top of a lasting subline, it will drown even more. 


TIM: Can you explain the delay factor with high pass filters? I didn't understand what you are trying to say. 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 10, 2016, 11:42:42 am


TIM: Can you explain the delay factor with high pass filters? I didn't understand what you are trying to say.
Don't think of it in terms of delay-but rather how long it takes them to "react".

As you go lower in freq-there is more phase shift/time in the filter.

As the filter gets steeper-there is more phase shift/time in the filter.

Put the the two together and it adds up pretty quick

I typically don't use more than a 24dB/oct slope.

If you need to get rid of lower freq and don't want to use a steeper slope (and the phase associated with it) a little trick is to put an eq point below the crossover filter.

You can do a lot of eq with minimal phase shift-at least as compared to the phase shift associated with a high or low pass filter.

Regarding "speed" the lower the freq the slower a driver will have to move.  at 40Hz it goes through 40 cycles in 1 second.  At 100Hz it must move much faster-because it has to go through 100 cycles in 1 second.

If your tops and subs are separated-then yes-at every seat you will need a different delay time.  No matter what speaker you use.

You have to choose a spot and live with it.

It is not just the delay time that works for alignment-sometimes you need to flip the polarity to get the best alignment-ALONG WITH the PROPER delay time.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 10, 2016, 12:14:45 pm
I understood that part but i didn't understand why in the first place would a high pass filter cause phase/time shift?
It starts getting a driver quieter under a certain frequency, how is that related to moving the phase of what's coming out of the speaker, how does this work?

2. So if i want to avoid this phase shift, instead of using a high pass filter a take an EQ for that box and kill everything below the frequency i don't want? How, why, isn't a HPS basicaly also an EQ just in a more agressive version?

3. It's not about the speed at which the driver moves at the certain frequency, it's about how fast it gets there. You are constantly thinking that i literally mean "speed" when i say speed, but actually i'm talking about acceleration. If driver one, gets a signal of power X, with that power the driver will produce let's say 110dB of the signal. But driver one will need 2ms from the moment of getting the signal to the moment of producing that singnal at 110dB, driver two will need 10ms to reach the same thing. Then driver one is going to sound sharper and give you more punch in the chest because it will be less "late" to the upper kick harmonic that follows it and the change in pressure of air in front of you will be happen faster. The air around you can't just go from nothing to pressure X at frequency X. The pressure will slowly rise during the time that driver is accelerating.
The faster the driver accelerates and stops , the sharper the transients will be.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Irvin Pribadi on February 10, 2016, 12:17:14 pm
As you go lower in freq-there is more phase shift/time in the filter.
As the filter gets steeper-there is more phase shift/time in the filter.
Put the the two together and it adds up pretty quick
I typically don't use more than a 24dB/oct slope.

Hey Ivan,
I've been passively following this thread and got a question: Does this affect both digital and analog filters alike? Thanks.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Art Welter on February 10, 2016, 12:21:07 pm

That subharmonic has to punch you fast, it has to be a "bum" not a "wooofff..." the way i see it is, once that subharmonic hits the amp, the driver needs to accelerate from standing still to that 40hz hit as fast as possible and then stop as fast as possible once it stops getting signal. These emminence drivers in the combination of the boxes they are in are simply to dull for that.
It will be to slow in accelerating to reaching that 40hz vibration, which will mean it will basicaly be late to follow the upper ~150hz kick, and then when the transient ends the cone will keep flopping around for too long insted of stopping fast. No matter what i do this is the way these boxes behave.

1)The more load you give them the less precise they become. If it's only a fast 40-50hz hit it might be somewhat decent, if it comes on top of a lasting subline, it will drown even more. 


2)TIM: Can you explain the delay factor with high pass filters? I didn't understand what you are trying to say.
1) When you push a driver (any driver) beyond Xmax, the magnet has little control over the cone, resulting in harmonic distortion, the harmonics of 50 Hz, that is 100, 150, 200, etc. may actually be louder than the fundamental.
Doubling Xmax (and power) results in 6 dB more output, the 18" drivers you are using may have only 6mm Xmax, while there are 18" with as much as 24mm Xmax, +12 dB more output potential. One of those drivers could equal the LF output of four of the lesser Xmax drivers.
2) Each "pole"(or "order") of a crossover introduces 90 degree phase shift. 6 dB per octave introduces 90, 12 dB 180 degree, 24 dB 360, etc.
360 degrees of phase rotation is one cycle. One cycle at 20 Hz lasts 1000ms/20=50ms. A 48 dB crossover introduces 720 degrees of phase shift, 100ms delay at 20 Hz. At 100 Hz, a 48 dB crossover would introduce 20ms delay.

The low end of a bass reflex (phase inversion) speaker at Fb lags the top end by 360 degrees before any HP has been introduced, the cumulative delay can be much longer when a high order HP is added.

Below is the frequency and phase response of a BR cabinet with a 38 Fb (port tuning) measured "raw", no HP or LP filters.

Art
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 10, 2016, 12:36:21 pm
Art, i understand well what is happening, you explained it nicely. But i don't understand why is it happening...

Basically you are saying that if i take sub, then put a highpass filter 24dB/octave at 40hz then all the frequencies in the area affected by the filter will be getting out of the sub 360 degrees late.
I'm really confused here and have no clue why a high pass filter would cause this.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 10, 2016, 12:45:29 pm
Wait, i've been thinking a bit while looking at the graphs you gave me. I don't really understand phase response in depth.
But something came across my mind. A driver at 50hz, will be moving faster then it will at 40hz. This means that physics won't allow 2 identical drivers in 2 identical boxes be in phase if they are not running at the same frequency. It's perfectly logical of course. You just imagine the sinewaves of both of them. That of course explains how the phase response changes in a linear way as the frequency rises, just like on the graph above. Now i'm thinking about the high pass filter once again... it will start decreasing the drivers movement under a certain frequency... but the phase should stay the same... it should just decrease it's amplitude, i still don't get it
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 10, 2016, 12:46:16 pm
Art, i understand well what is happening, you explained it nicely. But i don't understand why is it happening...

Basically you are saying that if i take sub, then put a highpass filter 24dB/octave at 40hz then all the frequencies in the area affected by the filter will be getting out of the sub 360 degrees late.
I'm really confused here and have no clue why a high pass filter would cause this.
No.

Phase is freq specific.

And when you say "all of the freq in the area of the filter", than can mean a lot of different things-depending on what are you calling "in the area".

The best way is to use a DSP and look at the phase response as you put different filters in-both freq and slope.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 10, 2016, 12:48:20 pm
No.

Phase is freq specific.

And when you say "all of the freq in the area of the filter", than can mean a lot of different things-depending on what are you calling "in the area".

The best way is to use a DSP and look at the phase response as you put different filters in-both freq and slope.

Yes, look at my upper post, i just sat to think about it and it of course logical. By "the area" i meant the frequencies that the high pass filter affects.
DSP and looking at phase response doesn't make much sense right now, i can see what is happening but i still won't understand why is it happening which is the point right now
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 10, 2016, 12:54:21 pm
Wait, i've been thinking a bit while looking at the graphs you gave me. I don't really understand phase response in depth.
But something came across my mind. A driver at 50hz, will be moving faster then it will at 40hz. This means that physics won't allow 2 identical drivers in 2 identical boxes be in phase if they are not running at the same frequency. It's perfectly logical of course. You just imagine the sinewaves of both of them. That of course explains how the phase response changes in a linear way as the frequency rises, just like on the graph above. Now i'm thinking about the high pass filter once again... it will start decreasing the drivers movement under a certain frequency... but the phase should stay the same... it should just decrease it's amplitude, i still don't get it

Think of it in the passive way.

Ac components (coils and capacitors) have a phase "aspect" to them-all be it opposite of each other.

Since the signal is AC-there is an impedance-which contains both resistive and reactive components.

These reactive components are what cause the phase shift.

The more poles (steeper) the filter, the greater the phase shift.  They just add up.

Different freq will be "in phase" and "out of phase" at different points in their curves.  It does not matter if they are in the same speaker cabinet or not.

This is why when you mix different freq you can get some addition and some subtraction-depend on the phase relationships.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 10, 2016, 12:55:51 pm
Yes, look at my upper post, i just sat to think about it and it of course logical. By "the area" i meant the frequencies that the high pass filter affects.
DSP and looking at phase response doesn't make much sense right now, i can see what is happening but i still won't understand why is it happening which is the point right now
The filter "affects" freq above it and below it.

How much depends on the range of interest.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Stephen Kirby on February 10, 2016, 08:19:24 pm
It still seems that Eugen is confused about the "speed" of the drivers motion.  As was pointed out, the speed of the cone's motion is related to the frequency and displacement it's going through.  If you look at FFT theory faster "speeds" (i.e. electrical rise times of non-sinusoidal waveforms) are made up of a combination of frequencies.  So the "faster" frequencies are reproduced by the other drivers in a system.  Which brings us back to the alignment of the various bandpasses so that the "impact" of the waveform coming from the upper bandpass elements of the system "speaks" together with the lower fundamental.  And that the first harmonic which is reproduced by both the sub and low/mid speaker doesn't get muddled between the two.
Any reactive system is going to have frequency dependent phase shift.  Whether it's an electronic crossover or a mechanical reproducer.  So now it becomes apparent how difficult it is to get the various components or harmonics of a sound to line up perfectly.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 10, 2016, 09:44:14 pm
It still seems that Eugen is confused about the "speed" of the drivers motion.  As was pointed out, the speed of the cone's motion is related to the frequency and displacement it's going through.  If you look at FFT theory faster "speeds" (i.e. electrical rise times of non-sinusoidal waveforms) are made up of a combination of frequencies.  So the "faster" frequencies are reproduced by the other drivers in a system.  Which brings us back to the alignment of the various bandpasses so that the "impact" of the waveform coming from the upper bandpass elements of the system "speaks" together with the lower fundamental.  And that the first harmonic which is reproduced by both the sub and low/mid speaker doesn't get muddled between the two.
Any reactive system is going to have frequency dependent phase shift.  Whether it's an electronic crossover or a mechanical reproducer.  So now it becomes apparent how difficult it is to get the various components or harmonics of a sound to line up perfectly.
Even a single driver (be it a woofer-full range speaker or HF driver) is a band pass device (meaning highs and lows roll off) and the phase response will look like an electronic active or passive filter that is assembled to be a bandpass filter.

The basic shape is such that the phase response will slope down from the low freq-then flatten out, and then slope down again at the high freq.

The slopes will more or less slope off as the freq response drops.

So the electronics follow the natural response-if everything is "perfect".

But it is not-so there starts to be more involved.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 11, 2016, 01:21:12 pm
It still seems that Eugen is confused about the "speed" of the drivers motion.  As was pointed out, the speed of the cone's motion is related to the frequency and displacement it's going through.  If you look at FFT theory faster "speeds" (i.e. electrical rise times of non-sinusoidal waveforms) are made up of a combination of frequencies.  So the "faster" frequencies are reproduced by the other drivers in a system.  Which brings us back to the alignment of the various bandpasses so that the "impact" of the waveform coming from the upper bandpass elements of the system "speaks" together with the lower fundamental.  And that the first harmonic which is reproduced by both the sub and low/mid speaker doesn't get muddled between the two.
Any reactive system is going to have frequency dependent phase shift.  Whether it's an electronic crossover or a mechanical reproducer.  So now it becomes apparent how difficult it is to get the various components or harmonics of a sound to line up perfectly.


I wrote that i'm not talking about speed but acceleration. I understand that the speed that a driver is moving at is frequency dependant. But if an 18 inch cone will be moving at XY meter a second at 40hz. It can't just instantly start moving at that speed from standing still. It will need some time to reach the speed and to stop again once it stops getting signal. On this, i think will depend how good and sharp transients sound trough that box.


Talking about phase problems... i started reading online. If i understood well, an the way and EQ works is if you want to cut a few dB on the 50hz band, it will insert a 50hz wave of opposite phase in the mix. Depending on the intensity of this wave everything at 50hz will get quietet/canceled out. Then there is an explanation that writes about why this causes phase problems at other frequencies. And i believe it also explains the "cut filter" delay problem you are telling me about. But i still don't understand it well. I don't understand why it's happening. I'm going to keep reading. 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 11, 2016, 01:37:00 pm
It still seems that Eugen is confused about the "speed" of the drivers motion.  As was pointed out, the speed of the cone's motion is related to the frequency and displacement it's going through.  If you look at FFT theory faster "speeds" (i.e. electrical rise times of non-sinusoidal waveforms) are made up of a combination of frequencies.  So the "faster" frequencies are reproduced by the other drivers in a system.  Which brings us back to the alignment of the various bandpasses so that the "impact" of the waveform coming from the upper bandpass elements of the system "speaks" together with the lower fundamental.  And that the first harmonic which is reproduced by both the sub and low/mid speaker doesn't get muddled between the two.
Any reactive system is going to have frequency dependent phase shift.  Whether it's an electronic crossover or a mechanical reproducer.  So now it becomes apparent how difficult it is to get the various components or harmonics of a sound to line up perfectly.

The main problem is, i still can't visualise on which principal the phase shift works. So we have a kick harmonic with a peak at 100hz. It's wide and has some material all the way from 70hz to 150hz. When that comes into a PA system it will start going out from both the sub and the low-mid driver. Now, i see that phase response if frequency dependant but can't connect these facts. There are to many holes in my knowledge here. I will keep reading online and then ask more when i start getting to some conclusions.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 11, 2016, 05:33:25 pm



Talking about phase problems... i started reading online. If i understood well, an the way and EQ works is if you want to cut a few dB on the 50hz band, it will insert a 50hz wave of opposite phase in the mix. Depending on the intensity of this wave everything at 50hz will get quietet/canceled out.
I have never seen an eq work like that.

And if it did-then the maximum amount of gain you could get would be 6dB.

And if you were mixing in a "out of polarity tone", then you would hear that tone.

Somebody is "pulling your leg" on that one.

An eq is basically a tuned filter that can add gain or attenuate around the freq it is rated for.

The early eqs were cut only and totally passive components.

It was not until active components were used that eq was able to "boost".  Basically an active circuit with the filter in the feedback look-so the amount of gain was determined by the amount of gain at that freq.  Gain can be plus or minus.

I say "around" because all eqs have a shape (like a bell).

So when you cut or boost a particular freq-you will ALSO boost freq above and below that.  How much?

It depends on the shape of the bell and the amount of the boost or cut added.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 11, 2016, 06:43:18 pm
I have never seen an eq work like that.

And if it did-then the maximum amount of gain you could get would be 6dB.

And if you were mixing in a "out of polarity tone", then you would hear that tone.

Somebody is "pulling your leg" on that one.

An eq is basically a tuned filter that can add gain or attenuate around the freq it is rated for.

The early eqs were cut only and totally passive components.

It was not until active components were used that eq was able to "boost".  Basically an active circuit with the filter in the feedback look-so the amount of gain was determined by the amount of gain at that freq.  Gain can be plus or minus.

I say "around" because all eqs have a shape (like a bell).

So when you cut or boost a particular freq-you will ALSO boost freq above and below that.  How much?

It depends on the shape of the bell and the amount of the boost or cut added.

Well the internet is pulling my leg then, didn't make sense to me either:

http://ethanwiner.com/EQPhase.html

QUOTE:
"Therefore analog equalizers work by intentionally shifting phase, and then combining the original signal with the shifted version. In fact, without phase shift they would not work at all!
Most digital equalizers mimic the behavior of analog equalizers, but with a completely different circuit design"

I'm not saying this is right, it just what i red...

Yes i know, they have a Q factor. I did some test with the DBX 2231 that we have in the club. If you play a 50hz sinewave through it. Give it just enough gain to make it turn it's -10dB green light on. And then pull the 20hz fader 6-7dB down. The -10dB light shuts off. Which means the 20hz fader still affects the 50hz area. That's quiet wide. I stopped pulling down 20 and 25hz faders after i realised this. Usually i would do this to to unload the subs where they are not efficient but i don't want the EQ to compromise my 40-50hz response.

However now you started explaning me that even any kind of lowcut filter at around 35hz will affect the 40-50hz response of my subs by delaying it and im totaly confused, reading as much as i can to understand what's happening.

But i will admit. No matter what i try. I prefer how these yamaha subs sound with no low cut filter of any kind compared to cutting them at 36hz. The pump out more low end energy. If i do use a low cut filter i somehow can't compensate for this loss by boosting the 45-50hz area. They still loose some meet down there. Yes they will become slightly more precise when i lowcut them but honestly more is lost then gained.
This is not because they stop playing under 36hz, they can't do shit below that. This is because the lowcut filter affects the rest of the response.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Stephen Kirby on February 11, 2016, 07:09:36 pm

I wrote that i'm not talking about speed but acceleration. I understand that the speed that a driver is moving at is frequency dependant. But if an 18 inch cone will be moving at XY meter a second at 40hz. It can't just instantly start moving at that speed from standing still. It will need some time to reach the speed and to stop again once it stops getting signal. On this, i think will depend how good and sharp transients sound trough that box.
 
The "transient" is a higher frequency component.  The subwoofer cone does not have to accelerate any faster than the sinusoidal rise time of the frequencies in it's bandpass.

Now there is a reactance in the response of the cone to the electrical signal.  The initial resistance to moving and the inertia to not wanting to stop.  This varies with how fast (frequency) to try to get it to do so.  So you get a frequency dependent phase shift in the actual output.  The way the compliance or springiness of the air around the cone (horn loaded, ported, sealed volume) is managed also will affect this.   But the transient of a sound or punchyness of the system is not directly related to this response to a demand for acceleration from the amplifier.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 11, 2016, 07:44:49 pm
The phase shift is the RESULT of a signal going through a filter.

Look at a simple single pole high pass filter (a capacitor)

It is in series with the load.

At a high freq the impedance is close to 0 ohms-so there is no attenuation.

As the freq goes lower, the impedance rises-resulting is less signal going to the load or a cut.  The impedance gets higher and higher as the freq goes lower and lower.

Think of it as a freq variable resistor.

An inductor works completely opposite.

Either type introduces a 90* phase shift for a single pole

WHen you put the two together, you get a tuned filter-at a specific freq.

There are different ways to combine them-series-parallel-T etc to get different results.

By adding a variable resistor to the pair- you can adjust how much loss there is across the circuit.

Ethan is a sharp fellow-but the idea that introducing phase shift to cause the eq action is not good.


You are welcome to not use a high pass filter on your subs, but be VERY CAREFUL.  A highpass filter is ALWAYS a good idea-on ANY loudspeaker.

ESPECIALLY if it is being pushed hard.

A high pass helps to prevent over excursion and damage.

Yes the overall response can be compromised a little bit-but in the "big picture", helping to prevent damage is a GOOD thing.

Of course if you don't push them hard-this is not a problem.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 12, 2016, 05:56:20 am
The "transient" is a higher frequency component.  The subwoofer cone does not have to accelerate any faster than the sinusoidal rise time of the frequencies in it's bandpass.

Now there is a reactance in the response of the cone to the electrical signal.  The initial resistance to moving and the inertia to not wanting to stop.  This varies with how fast (frequency) to try to get it to do so.  So you get a frequency dependent phase shift in the actual output.  The way the compliance or springiness of the air around the cone (horn loaded, ported, sealed volume) is managed also will affect this.   But the transient of a sound or punchyness of the system is not directly related to this response to a demand for acceleration from the amplifier.

That reactance is what i am talking about.
Damn, i think i am probably using the wrong terminology to explain what i'm trying to say. Take a listen at the sub-line in this song:   https://www.youtube.com/watch?v=uzf9cxlmmcs

Assuming you have something decent to use for hearing the sub in this song, you can hear how it's not just a simple sterile bassline at 40-50hz. It's modulating and pulsating. Plus, every kick is followed by a short lasting increase in the amount of sub. If you put this thing through an RTA analyzer you can see it all.

On these yamaha subs, all of these things will mold together, you will feel the energy and you will feel it around the frequency it's at but all of these modulations will be soft and bearely felt. It will feel like there is just a lot of sub in the song, not like there is an entire weird beat in the sub.

On a set of really good subs it's a much different story. You feel each one of these details perfectly precise. Every time the sub does this modulation it's like a separated small hit in the chest. It's like, there are two different basselines on top of each other, but on yamaha subs they kind of drown each other.
This is what i call, boxes with bad transient response. Maybe i'm using the wrong terminology. Can you understan me closer with this example?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 12, 2016, 06:07:18 am
The phase shift is the RESULT of a signal going through a filter.

Look at a simple single pole high pass filter (a capacitor)

It is in series with the load.

At a high freq the impedance is close to 0 ohms-so there is no attenuation.

As the freq goes lower, the impedance rises-resulting is less signal going to the load or a cut.  The impedance gets higher and higher as the freq goes lower and lower.

Think of it as a freq variable resistor.

An inductor works completely opposite.

Either type introduces a 90* phase shift for a single pole

WHen you put the two together, you get a tuned filter-at a specific freq.

There are different ways to combine them-series-parallel-T etc to get different results.

By adding a variable resistor to the pair- you can adjust how much loss there is across the circuit.

Ethan is a sharp fellow-but the idea that introducing phase shift to cause the eq action is not good.


You are welcome to not use a high pass filter on your subs, but be VERY CAREFUL.  A highpass filter is ALWAYS a good idea-on ANY loudspeaker.

ESPECIALLY if it is being pushed hard.

A high pass helps to prevent over excursion and damage.

Yes the overall response can be compromised a little bit-but in the "big picture", helping to prevent damage is a GOOD thing.

Of course if you don't push them hard-this is not a problem.

So i have been misinformed.
I understand how a capacitor does a low cut but still don't get the logics behing phase shifting. It will decrease the amplitude of lower frequencies. Why does that have anything to do with the phase of the signal/different parts of signal.

Yes i know it is, the problem is i do push them as hard as i can. I watch to make them not clip but do push them hard. They work well... i hope they will keep working well.
I even sometimes used them to fill in only the very bottom of the sub lines. I have my own 4 EV T18 horn loaded boxes with rcf l18s800 drivers. They are currently not working because they were hand winded and didn't last. I will recone them then i get some money but while i used to have them i would put them in the middle of the stage. Used them from 45 to 100hz and then the yamahas would work only under 45 hertz. This would work very nice because the t18 gave me a sharper sub response, i could feel the kick out of them much nicer then out of floppy yamaha subs. But then the yamahas would start filling below 45hz giving me a very nice amount of energy in the air and a decent low end extension. I will do this setup again when i recone my subs.

This is what it looked like when i did this combination.
And yes, the mid-high boxes are not hanging like this anymore. This was a terrible setup for them:

https://fbcdn-sphotos-h-a.akamaihd.net/hphotos-ak-xfp1/t31.0-8/10842316_1587881531443701_6729732226219140778_o.jpg
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 12, 2016, 07:53:37 am
So i have been misinformed.
I understand how a capacitor does a low cut but still don't get the logics behing phase shifting. It will decrease the amplitude of lower frequencies. Why does that have anything to do with the phase of the signal/different parts of signal.


A capacitor can cut the lows OR the highs.  The same thing with an inductor.

It depends on how it is used in the circuit.

The same parts are used for high pass and low pass circuits-just used completely opposite.

Phase is not an easy thing to describe or understand.

Sometimes a phase shift (it will be a different amount of phase at different freq) can be a good thing.

It is not always bad-but that is how people often think of it.

Often an eq adjustment that corrects the amplitude will ALSO correct the phase shift that was associated with the amplitude abnormality to begin with.

So in this case a phase shift is a GOOD thing.

The phase response across various components can either make the signal appear to be earlier or later in time.

If you really want get confused-look into the phase response of the impedance of a loudspeaker.

Sometimes the phase response of the impedance is more harmful to an amplifier than the actual impedance

If it is to reactive (either capacitive or inductance wise) the amp will have a hard time driving it-even though the impedance number may be fine.

A GREAT example of this was the old Servodrive speakers.

I had to work hard to find out how to keep may amps (crown 2400 and crest 8001s) from shutting down from heat when driving just 1 cabinet per side-and then not even driving it hard.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 12, 2016, 07:59:11 am
We are not going to get far this way. There is to much theory to know before being understand what is happening in depth. I started reading this, hope it's some good material:

http://sound.westhost.com/ptd.htm
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Stephen Kirby on February 12, 2016, 04:50:53 pm
Eugen, what I hear in your referenced track is compressor pumping in the bass.  The level of that low frequency drone is modulated by the fairly high kick drum.  Which reminds me of the disco '70s where a sub was a CV W bin that didn't really go that low and so producers found that hitting a 5 gallon ice cream carton with a tympani mallet gave a dead thump somewhere between 80 and 100Hz that would move the patrons in the discos given the system of the time.

That thump range is right where the T18s have a very strong peak.  And so that setup with them will sound like that recording where they accentuate the kick sound.  While the ported Yammies struggle to play the drone.  Which the EV's won't reproduce barely at all.

When you say that the referenced track sounds tighter on better subs are you talking about being in the same room with the same locations of the speakers?  Some of your problem may be your room.  There is a great article linked in the Basement from a top pro about the LF overhang or reverberation in some venues.

But bottom line, it really sounds like you are trying to get more low frequency extension than the gear can produce.  As Ivan has pointed out many time, roll off is not a brick wall.  Most any system can be made to produce very low frequencies.  It's just a matter of how loudly compared to the rest of the system's output.  If you put those Yamahas in a living room home theater and equalized the snot out of them, you could probably get 20Hz extension at levels suitable for watching TV.  But if you want to get 30-35Hz out of them at dance club levels it ain't gonna happen.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 12, 2016, 05:26:55 pm
Eugen, what I hear in your referenced track is compressor pumping in the bass.  The level of that low frequency drone is modulated by the fairly high kick drum.  Which reminds me of the disco '70s where a sub was a CV W bin that didn't really go that low and so producers found that hitting a 5 gallon ice cream carton with a tympani mallet gave a dead thump somewhere between 80 and 100Hz that would move the patrons in the discos given the system of the time.

That thump range is right where the T18s have a very strong peak.  And so that setup with them will sound like that recording where they accentuate the kick sound.  While the ported Yammies struggle to play the drone.  Which the EV's won't reproduce barely at all.

When you say that the referenced track sounds tighter on better subs are you talking about being in the same room with the same locations of the speakers?  Some of your problem may be your room.  There is a great article linked in the Basement from a top pro about the LF overhang or reverberation in some venues.

But bottom line, it really sounds like you are trying to get more low frequency extension than the gear can produce.  As Ivan has pointed out many time, roll off is not a brick wall.  Most any system can be made to produce very low frequencies.  It's just a matter of how loudly compared to the rest of the system's output.  If you put those Yamahas in a living room home theater and equalized the snot out of them, you could probably get 20Hz extension at levels suitable for watching TV.  But if you want to get 30-35Hz out of them at dance club levels it ain't gonna happen.
And it could be the room modes that are stacking up at certain freq and locations that are "sucking out" the notes he is looking for.

There are MANY variables in sound and getting obsessed on one or looking for the "magic bullet" is often a waste of time and money.

You have to know WHICH BULLET to go looking after in YOUR PARTICULAR space.

What works in somebody elses room does NOT mean it is going to work in yours.  But it might.  It just depends on what the REAL problem is.

Until the problem has been identified-it is hard to say what the solution is. 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 13, 2016, 08:27:19 am
Eugen, what I hear in your referenced track is compressor pumping in the bass.  The level of that low frequency drone is modulated by the fairly high kick drum.  Which reminds me of the disco '70s where a sub was a CV W bin that didn't really go that low and so producers found that hitting a 5 gallon ice cream carton with a tympani mallet gave a dead thump somewhere between 80 and 100Hz that would move the patrons in the discos given the system of the time.

That thump range is right where the T18s have a very strong peak.  And so that setup with them will sound like that recording where they accentuate the kick sound.  While the ported Yammies struggle to play the drone.  Which the EV's won't reproduce barely at all.

When you say that the referenced track sounds tighter on better subs are you talking about being in the same room with the same locations of the speakers?  Some of your problem may be your room.  There is a great article linked in the Basement from a top pro about the LF overhang or reverberation in some venues.

But bottom line, it really sounds like you are trying to get more low frequency extension than the gear can produce.  As Ivan has pointed out many time, roll off is not a brick wall.  Most any system can be made to produce very low frequencies.  It's just a matter of how loudly compared to the rest of the system's output.  If you put those Yamahas in a living room home theater and equalized the snot out of them, you could probably get 20Hz extension at levels suitable for watching TV.  But if you want to get 30-35Hz out of them at dance club levels it ain't gonna happen.

Yes you heard it well. There is a side chained compressor triggered by the upper kick, it pumps sub down at about 40-50hz. That "pumped in" short lasting sub will from some sub setups last short, be nicely in time with everyhing following it in the upper range. From some subs it will be bearely noticable and molded with the rest of the sub line, it will also sound late and sloppy. This is the main problem with the yamahas. You put that on top of the very bad reproduction in the 70-100hz area and everything below 100hz sounds as soft as a marshmallow. This also varietes depending on how loaded the sub is in the moment. This song from boddika that i linked, if you listened to it on the yamaha system, which i did many times, i use if for eq-ing subs sometimes.
You couldn't tell any of what you heard up there. Compressor pumping in sub following the kick? You' bearely notice it only if you are directly in front of the subs.
When we rented the other 2-way sub setup that i linked you a picture of a few days ago. 6 HOG horns with B&C 18-s and 6 horn loaded kickers running up to 150hz. Those things... you could tell exactly how it's produced and where the sub is pumping in.
It's now about the power, it's about the softness and the mudiness of the yamaha subs. Yes i am comparing the setup in the same place in the same club. The yamahas will definitley work better in a mono block because then when you are in front of the stage you stay in the power alley where sub is more clean. But they are still bad.
What i'm trying to do here is realise the technical explanation behind this to understand why they are bad. My opinion is that those drivers have a very bad "reactance factor" that we talked about. And i think that's what's called "transient response" in proper terms.

Yes, the T18's have a strong bump in that 80-120 hertz range which makes them really good "kickers". Especially with the rcf drivers i have inside them which are stiffer and more precise then the emminence ones. But aT18 by itself is terrible in low end extension. When you couple 4 of them together they can do some damage down to 40hz but that's about it.
So yes, they can't play the low end drone at all while the yamahas struggle to. So the setup that i mentiones where the T18's play 45-120 and the yamahas play 30-45 is basically trying to force more low end out of a system that wasn't designed for that. But it kind of works and i used to be quiet happy with the results. I just have to recone my T18's so i can do that again.
Tha yamahas will do some pressure down at 35-40hz, especially when low passed at 45 so they are not loaded with anything higher.
When you make them go only this low they play their role quiet decent because their sloppines is not that important down there. They just fill in some energy while the t18's play the upper parts with beat and transients in the sub lines. But when the yammie is a full range sub... soft soft soft and only soft. No punch, woof woof woof woof , never a bang...

Yes i understand that i can get the subs quieter and then eq them to go lower. That's quiet much what i do when i run only the yamahas. Force some 35-40hz sub out of them and get 50-60 area a bit quieter so you can hear the lower parts because the 50-60hz area is not overpowerng them. But here i was told that's a bad idea because i'm pushing them below the tunning frequency.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 13, 2016, 08:33:40 am
And it could be the room modes that are stacking up at certain freq and locations that are "sucking out" the notes he is looking for.

There are MANY variables in sound and getting obsessed on one or looking for the "magic bullet" is often a waste of time and money.

You have to know WHICH BULLET to go looking after in YOUR PARTICULAR space.

What works in somebody elses room does NOT mean it is going to work in yours.  But it might.  It just depends on what the REAL problem is.

Until the problem has been identified-it is hard to say what the solution is.

Of course. But the comparisons i'm talking about are different subs in the same place of the same club so...
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 13, 2016, 12:01:41 pm

Yes i understand that i can get the subs quieter and then eq them to go lower. That's quiet much what i do when i run only the yamahas. Force some 35-40hz sub out of them and get 50-60 area a bit quieter so you can hear the lower parts because the 50-60hz area is not overpowerng them. But here i was told that's a bad idea because i'm pushing them below the tunning frequency.
As usual-it depends.

There is nothing wrong with doing (eq wise) what you describe-AS LONG AS you aren't pushing the system hard.

When you turn it up-THAT is when you are going to start running into possible trouble.

How much is "to much"?  When it starts to sound bad or speakers tear up.

Until that point- you are fine with it.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 13, 2016, 12:03:44 pm
Of course. But the comparisons i'm talking about are different subs in the same place of the same club so...
The reason for my comment was that was not made clear to us.  You (if I am not mistaken-I could be wrong) only talked about the other system-not that it is in same physical place.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 13, 2016, 12:18:24 pm
Well i run them of of yamaha p7000s amps that were designed to work with them. I do push them hard but never let them touch the clipping point. These amps are not powerfull enough to get these boxes to significant distortion. Plus, thay have done many parties set up like this. I had no problems of any kind with them.

Yes, i always talked about comparisons in the same room since most of my experience comes from this club. We also did a few parties in the smaller part of the club for about 150 people which is acousticaly a lot better then the larga space. I would use only to yamaha subs there. They did sound better overall but still soft and sloppy.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 13, 2016, 01:23:07 pm
Well i run them of of yamaha p7000s amps that were designed to work with them.
This is a comment that gets said  A LOT, along with "Well this sub in the product line was "designed" to work with the others.

I say BS.

No amp is designed to work with a sub or vice versa.  If the power is complementary-then fine-but there was no "design" going into it.

The same for subs and tops of a product line.  Except for the physical size-looks etc, there is no "design" to make them work any better than another brand or product.

If it makes people "feel better", then OK.  But the word "design" is often misunderstood.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 13, 2016, 01:28:02 pm
This is a comment that gets said  A LOT, along with "Well this sub in the product line was "designed" to work with the others.

I say BS.

No amp is designed to work with a sub or vice versa.  If the power is complementary-then fine-but there was no "design" going into it.

The same for subs and tops of a product line.  Except for the physical size-looks etc, there is no "design" to make them work any better than another brand or product.

If it makes people "feel better", then OK.  But the word "design" is often misunderstood.

Yeah but this was sold as a kit in the store. It was a pair from yamaha. 2 subs and 2 tops with 2 p7000s amps. The power is of course matched.

However i find these yamaha subs work better with my old Peecker sound TVA 1800amps that are about the same power as the p7000s but have a much more powerfull power supply and a lot more condenser capacity so they keep more control over the drivers at low frequencies. They are 18 years old but were very expensive back in 97.

Peecker sound is a company from italy:

http://i30.photobucket.com/albums/c316/athlon-64/IMG_2507_zpsmc56iglm.jpg~original

I have 2 of these. 2x900w at 4 ohms.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 13, 2016, 04:16:51 pm
Yeah but this was sold as a kit in the store. It was a pair from yamaha. 2 subs and 2 tops with 2 p7000s amps. The power is of course matched.

However i find these yamaha subs work better with my old Peecker sound TVA 1800amps that are about the same power as the p7000s but have a much more powerfull power supply and a lot more condenser capacity so they keep more control over the drivers at low frequencies. They are 18 years old but were very expensive back in 97.

Peecker sound is a company from italy:

http://i30.photobucket.com/albums/c316/athlon-64/IMG_2507_zpsmc56iglm.jpg~original

I have 2 of these. 2x900w at 4 ohms.
Just because it was sold as a "kit" does not mean it was "Designed" to work best together.

If you use that "thought process" then the amps would not work with other speakers.  Which of course is not true.

Or you would have to ask yourself-what speakers are Powersoft or Lab Gruppen amplifiers "designed" to work with?

The capacitors in the power supply have nothing to do with control over the low freq.  That is determined by the output section of the amplifier-NOT the power supply

All they are is the power supply reserve-which basically determines how much power they can supply for how long.

But some people confuse a "sloppy sounding" amplifier as not having control over the low freq.

But if the power supply is quickly running out of "gas", then it will sag and get "sloppy".  But the control over the speaker will be the same.

They are different parts of the circuit.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 14, 2016, 07:05:34 am
Well yes but i meant, if they were sold as a kit that means the amp definitly won't overpower the box while it's under the clipping point. They probably wouldn't sell a 1.5kw amp wih an 800w rms box. Not saying it's not a good idea having a overly powerfull amp but with kits like these i doubt that would happen.

I understand but for some reason the yamaha boxes and my EV T18 boxes sound less powerfull and less controlled with the yamaha amps then my old peecker sound amps. You can here this significantly as the frequency goes lower. I remember with my boxes, it was like when there is a hard low bassdrop the amp looses control over the cone, and you can hear significant distortion. With my amps i could hear loads more of controlled power in the bottom end.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 14, 2016, 10:19:16 am
Well yes but i meant, if they were sold as a kit that means the amp definitly won't overpower the box while it's under the clipping point. They probably wouldn't sell a 1.5kw amp wih an 800w rms box. Not saying it's not a good idea having a overly powerfull amp but with kits like these i doubt that would happen.

I understand but for some reason the yamaha boxes and my EV T18 boxes sound less powerfull and less controlled with the yamaha amps then my old peecker sound amps. You can here this significantly as the frequency goes lower. I remember with my boxes, it was like when there is a hard low bassdrop the amp looses control over the cone, and you can hear significant distortion. With my amps i could hear loads more of controlled power in the bottom end.
Sorry, but I totally disagree.

If you want to power a 800 watt continuous cabinet "properly" you should use a 3600 watt amp.

That would allow for the peaks to come through fine.

Now IN REALITY, especially in a dance club that is a STUPID idea.

A "standard" powering for a loudspeaker is around 1.5 to 2x the continuous rating for NORMAL material.  NOT heavy dance material that goes on for many hours.

Loudpseakers are rated for a specific waveform for a specific time.

Change either one and the ratings are no longer valid.

Different usages require different limiter setups.

In many/most cases a "dance" system should be limited to 1/2 or 1/4 long term power.

I know that sounds crazy-but is essential if the system is going to be pushed hard-if you want the speakers to last.

There is no "correct: size amp for a loudspeaker-only a correct size for a SPECIFIC application.

Different applications will be different.

Just because it was sold as a "package" only means that is what somebody thought would be a decent match up-NOT that they are designed for each other.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 14, 2016, 12:29:42 pm
That's the logics i took when i tried briding my peecker sound amps to get 1800w into 8ohms for each 18" cabinet with rcf l18s800 inside. My t18's that i mentioned...

As i also mentioned, 3 of them are waiting for a recone kit since that night :).

I ran the amps under 1/2 of that power which should still be around the RMS rating of those drivers.

Of course, there are 2 factors. First is, it was a dnb party. Basically it's close to pushing 3 sinewaves between 30 and 100hz through them with no stops and pushing them as hard as possible for 6 hours in a row with that material.

An there is the other factor. Only 3 drivers died. The ones that have been rewinded by hand of course. The reconed one is still working perfectly.

These yamaha boxes are rated 550w RMS, 1100w Program. These amps give them about 1000w before clipping. We have a limiter so the amps never clip but we quiet much run them as hard as possible sometimes for over 7 hours with no stops. They have been doing that for 6 years now. 2, sometimes 3 times a week.
They are still running perfectly. Only one box needed the drivers replaced 2 years ago but because of someones mistake, the amp clipped hard. That box with drivers much newer, is not working any better then the ones tortured for 6 years.

So i don't know what exactly do you mean when you say 1/2 of the rated long term power. If we are running a dnb party with constant sublines. I'm pushing subs as hard as possible but i never let them clip. What does that mean, how much power are they getting on average from the amp that will clip over 1000w at 4 ohms?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 14, 2016, 01:26:44 pm

So i don't know what exactly do you mean when you say 1/2 of the rated long term power. If we are running a dnb party with constant sublines. I'm pushing subs as hard as possible but i never let them clip. What does that mean, how much power are they getting on average from the amp that will clip over 1000w at 4 ohms?
This is a very complicated question.

The actual power depends on what the impedance of the speaker is at the freq that is being applied.

The impedance is NOT what it is rated at-no loudspeaker is.

It varies quite a bit and you may not be delivering the power you think you are-at the freq involved.

What I suggested was setting the limiter at 1/4 to 1/2 power, with a long attack time 3 seconds is a typical sub attack time at that power level.

But all limiters have an attack time.  They don't react immediately. So peaks can get through but it is the average level that does the damage.

It is not exactly easy to measure the actual voltage going to the speaker.

So it is a combination of freq-impedance-voltage and time that determines whether or not damage will occur.

It is good that you have not been having problems.  If you keep doing the same thing you should be fine.

And that is all that matters.

It is when you have problems tearing up drivers that it gets more complicated in trying to solve.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 14, 2016, 02:44:56 pm
Of course. Since i'm not damaging the PA as time has shown i don't have much to worry about. But still, it's good to know.
The thing is i tend to push these yamahas as far as i can with long lasting sublines. Not peakes.
I used to get them near clipping levels with a subline that is really like a sinwave. That probably means running them around 700-800w average when the subline is going through.
They do survive however... 

And yes i understand drivers are reactive and change impedance depending on the frequency. That's why it's not reccomended running the amp at the lowest impedance it can work at. If it's running an 8ohm load and is capable of running a 4 ohm load then it still won't be tortured even if the driver is very reactive.

Also, would it be an idea that makes sense...
Using a compressor with a slow attack time to make the transients and peaks stand out more.

If there is a sub line at 50hz with short hits of 60hz sub on top of that and i want those short hits of 60hz sub to stand out more then i could insert a compressor that cacthes peaks but has an attack time of maybe 20-30ms. So the transient goes through.

If i don't like the fact that it's compressing everything just to get that 60hz hit out then i could insert it only on the sub matrix on the behringer x32 so it affects only subwoofer.
I use matrix sends on the x32 as a crossover.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: g'bye, Dick Rees on February 14, 2016, 03:10:34 pm
I use matrix sends on the x32 as a crossover.

So what kind of slope does that give you?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 14, 2016, 04:07:35 pm
So what kind of slope does that give you?

I can pick between 12 and 24db/octave. The matrix sends are designed to be used as a crossover if you want.
I use 24db/octave
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 14, 2016, 05:02:55 pm

And yes i understand drivers are reactive and change impedance depending on the frequency. That's why it's not reccomended running the amp at the lowest impedance it can work at. If it's running an 8ohm load and is capable of running a 4 ohm load then it still won't be tortured even if the driver is very reactive.


Typically the impedance will mostly be HIGHER than the rated impedance.

Yes there may be a few freq that are lower-but if they are much lower then the cabinet should be rated at the next lowest standard freq.

Amps can drive lower impedances than they are rated for-but for how long it depends.

Remember that what we are talking about is not "exact", but has a lot of variables involved.

The main reason for not loading an amp down to its lowest rating is that the power supply will have more reserve for longer duration signals.

But many amps are designed to drive 2 ohm loads and can do it just fine.

You can look at the power ratings at the different impedances to see how well it can drive lower impedances

If the power goes up as the impedance goes down, then it is able to drive lower impedance loads just fine.

But if the power does not go up or only a little bit when you go from 4 to 2 ohms, then you are at the limit around 4 ohms.

It might can drive a 2 ohm load-just not very well or with much "authority".
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 14, 2016, 05:53:39 pm
Typically the impedance will mostly be HIGHER than the rated impedance.

Yes there may be a few freq that are lower-but if they are much lower then the cabinet should be rated at the next lowest standard freq.

Amps can drive lower impedances than they are rated for-but for how long it depends.

Remember that what we are talking about is not "exact", but has a lot of variables involved.

The main reason for not loading an amp down to its lowest rating is that the power supply will have more reserve for longer duration signals.

But many amps are designed to drive 2 ohm loads and can do it just fine.

You can look at the power ratings at the different impedances to see how well it can drive lower impedances

If the power goes up as the impedance goes down, then it is able to drive lower impedance loads just fine.

But if the power does not go up or only a little bit when you go from 4 to 2 ohms, then you are at the limit around 4 ohms.

It might can drive a 2 ohm load-just not very well or with much "authority".

I understand.
My peecker sound amps are rated 565w @ 8 ohms and 900w @ 4 omhs. And guys from peecker sound tech support told me that i should not use them at 2 ohms.

This factor of changing impedance of a driver, does it variate from a driver to a driver? Is it anywhere in the specs? And how is it related to frequency?
If i have an 18 sub rated at 8 ohms, what can i expect from it. Impedance jumps at higher or lower frequencies?

Are these variations significant enough to really make the amp give less power to the driver because overall it's impedance end's up over the rated impedance?

How does this factor make the amp have a hard time pushing the driver? It's sayed that these variations can start torturing the amp.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: g'bye, Dick Rees on February 14, 2016, 06:30:56 pm

This factor of changing impedance of a driver, does it variate from a driver to a driver? Is it anywhere in the specs? And how is it related to frequency?


Well, Danley publish a graph of impedance:frequency.  I suspect few others do although they might furnish info upon request.  Here's a link:

http://www.danleysoundlabs.com/danley/wp-content/uploads/2012/04/TH-118-spec-sheet.jpg
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 14, 2016, 07:24:15 pm
I understand.
My peecker sound amps are rated 565w @ 8 ohms and 900w @ 4 omhs. And guys from peecker sound tech support told me that i should not use them at 2 ohms.

This factor of changing impedance of a driver, does it variate from a driver to a driver? Is it anywhere in the specs? And how is it related to frequency?
If i have an 18 sub rated at 8 ohms, what can i expect from it. Impedance jumps at higher or lower frequencies?


All that means is that those amps are not rated for 2 ohm operation.

But many other amps are.

I never said the impedance changed.  I said it varies with freq

Look at any impedance graph of a loudspeaker and you will see what I mean.

The "rating" is the simple number that the loudspeaker is closest to.

At some freq it will be correct, but at other freq it will be wrong.

Some speakers that are rated for 8 ohms could be 50 ohms at some freq. and 6 ohms at others.

Some speakers may have the impedance above the rated impedance and never go as low as the rating.

It varies speaker to speaker.

The impedance CURVE can give a lot of information regarding the tuning of the cabinet and so forth.

The "simple number" is only a rough indicator of the actual load.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Scott Holtzman on February 14, 2016, 09:39:41 pm
All that means is that those amps are not rated for 2 ohm operation.

But many other amps are.

I never said the impedance changed.  I said it varies with freq

Look at any impedance graph of a loudspeaker and you will see what I mean.

The "rating" is the simple number that the loudspeaker is closest to.

At some freq it will be correct, but at other freq it will be wrong.

Some speakers that are rated for 8 ohms could be 50 ohms at some freq. and 6 ohms at others.

Some speakers may have the impedance above the rated impedance and never go as low as the rating.

It varies speaker to speaker.

The impedance CURVE can give a lot of information regarding the tuning of the cabinet and so forth.

The "simple number" is only a rough indicator of the actual load.

This discussion happens, in part, because we use the term "impedance of a speaker, or driver"  The correct term is nominal impedance.  It is a value that nominally represents the average impedance under average conditions.  It is fine for back handed calculations of amp and speaker compatibility. 

What it is not is a constant to be used in formulas for sizing amplification requirements.  For that you need an integral of the curve that Ivan mentioned.   

In engineering we use the term Monte Carlo analysis to describe complex multi-parameter systems.  You analyze all the possibilities you find the limits.  Then engineer your system for your safety factor at those limits.

Frankly, it's a lot to digest for anyone with high level math background.   So many moving numbers. 

It all starts with the variability of the source material then branches out from that point.

We all want neat answers, what speaker should I use, what amp.  The truth is every decision is tainted by practicality.  Tom's  "the speaker has to fit through the door" principal. 

Then you add in the economic factors and lastly the emotional ones (purple driver syndrome.  great article BTW) and frankly our answers come out sounding like they were written by product liability lawyers. 

Your music, your room, your gear, your money and your fingers on the knobs.   

That's when you have to get real.  If you are blowing shit up you need to change the way you are doing things.  If your customers are paying you what you want for the gear you bring and are happy with the service you provide our opinion really doesn't matter.

I am starting to swerve off course, I think I made my point.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 15, 2016, 06:39:38 am
I see, but these graphs show drastic variations in impedance.
How do these impedance changes affect the amp? Would a driver with less drastical impedance jumps and drops over the frequency range sound better and why?
I didn't see things this way. I tought the amp will give a spaker roughly the same amount of power over the entire frequency range if the input voltage at all frequencies doesn't change.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: g'bye, Dick Rees on February 15, 2016, 06:44:56 am
I see, but these graphs show drastic variations in impedance.
How do these impedance changes affect the amp? Would a driver with less drastical impedance jumps and drops over the frequency range sound better and why?
I didn't see things this way. I tought the amp will give a spaker roughly the same amount of power over the entire frequency range if the input voltage at all frequencies doesn't change.

I assume the graph represents sine wave response whereas program material contains more frequencies/harmonics, so I would further assume the curve would appear less drastic.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 15, 2016, 07:40:10 am
I see, but these graphs show drastic variations in impedance.
How do these impedance changes affect the amp? Would a driver with less drastical impedance jumps and drops over the frequency range sound better and why?
I didn't see things this way. I tought the amp will give a spaker roughly the same amount of power over the entire frequency range if the input voltage at all frequencies doesn't change.

The term "power amplifier" is mostly wrong.  But that doesn't keep people from using the term-just like phase when it should be polarity :(

Think of the amp as a VOLTAGE amplifier-NOT a power amplifier.  Because it IS a voltage amp and NOT a power amp

IF it was a power amp-then the output voltage (and resultant power) would be jumping all over the place due to the different impedance at different freq.

But for the most part (until we hit the limits) it is a constant voltage amplifier.

In fact with the higher impedance peaks-it actually "likes" the load better.  It is easier to "drive"-produces less heat-has more headroom and so forth.

It is also related to another incorrect term when talking about sensitivity 1W.  NO manufacturer applies 1 watt when doing this measurement.  They apply 2.83V (which happens to be 1 watt @ 8 ohms)

However if they were actually applying 1 watt-then the voltage at the freq where the impedance is higher than 8 ohms would HAVE to be higher (in order to get 1 watt)

This would produce a higher output at those freq and the response would get even more ragged.

But they apply a constant 2.83V-and the power will vary with freq

So at some freq-there is much LESS than 1 watt being applied.

So the term 1 watt (when talking about sensitivity) is technically wrong.  The CORRECT term is 2.83Volts-because that is what is being applied-NOT power.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 15, 2016, 08:49:53 am
So if we have 2 drivers rated at 4 ohms nominal and one of them is having changes/jumps and at almost 50% of the frequencies it reproduces it hits almost 8 ohms impedance.
Then we have the second driver which is also rated at 4 ohms nominal but for for the most part it stays near 4 ohms and doesn't have that many peaks at higher impedances.
Then the amp is going to have an easier time driving the first driver but the second driver will be using the amps power better and be louder over most of the frequency spectrum.
Assuming that both drivers have the same sensitivity.

And yes i know a power amp is basicali a voltage amp and that 2.83V is used for sensitivity measurements.
But this also means that when you have two drivers rated at 100dB sensitivity at 1khz. Unless i take the impedance graph from both of them and compare the actual power going into both drivers under those conditiones i am not doing a good side by side comparison?

One of the drivers might be a 10ohm load at 1khz, the other one might be an 8 ohm load at 1khz even though they are both rated at 8 ohms nominal?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 15, 2016, 12:19:04 pm
So if we have 2 drivers rated at 4 ohms nominal and one of them is having changes/jumps and at almost 50% of the frequencies it reproduces it hits almost 8 ohms impedance.
Then we have the second driver which is also rated at 4 ohms nominal but for for the most part it stays near 4 ohms and doesn't have that many peaks at higher impedances.
Then the amp is going to have an easier time driving the first driver but the second driver will be using the amps power better and be louder over most of the frequency spectrum.
Assuming that both drivers have the same sensitivity.

And yes i know a power amp is basicali a voltage amp and that 2.83V is used for sensitivity measurements.
But this also means that when you have two drivers rated at 100dB sensitivity at 1khz. Unless i take the impedance graph from both of them and compare the actual power going into both drivers under those conditiones i am not doing a good side by side comparison?

One of the drivers might be a 10ohm load at 1khz, the other one might be an 8 ohm load at 1khz even though they are both rated at 8 ohms nominal?
I have never seen a speaker that has a sensitivity rated at 1KHz.

That could be a pretty useless measurement.

If 1Khz was a couple of dB higher than everything else, then the speaker would have a rating that would be false and people would expect it to be louder than it is.

A sensitivity rating should be an average across the intended freq range.  NOT a peak or a dip in the response.

I would worry about the power an amp is delivering in terms of looking at different speakers impedances.

An amp will not be any louder because of some impedance peaks.  It will simply run a tad bit cooler when reproducing those freq.

The impedance ratings are a "nominal standard" rating.

And the TRUTHFUL impedance (some sort of an average) may be quite different than the "simple number" says.

But people just don't seem to understand anything other than 2-4-8-16 ohms.  If you give a speaker a real rating of 6 ohms, it confuses lots of people because they can't find an amp rating for 6 ohms.

So people will give the closest "standard" number to avoid confusion-but it is not "correct".
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 15, 2016, 12:31:18 pm
Okay so sensitivity measurements should be taken as an average over the entire spectrum.

How? If a speaker is rated 8 ohms nominal. And it has a peak at 11ohm@500hz. That means that the amp won't be able to give the speaker the same amount of power at 500hz as at some frequency where the impedance is lower. And that means that it will run quieter ar 500hz because of the impedance jump.

Unless you have an amp powerfull enough and can boost the 500hz fader on the EQ a little bit.

On the other hand if we have another 8ohm driver but this one is keeping the 8ohm impedance at 500hz. That driver will run louder at 500hz then the previous one because it will pull more power from the amp?
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 15, 2016, 12:56:21 pm
Okay so sensitivity measurements should be taken as an average over the entire spectrum.

How? If a speaker is rated 8 ohms nominal. And it has a peak at 11ohm@500hz. That means that the amp won't be able to give the speaker the same amount of power at 500hz as at some frequency where the impedance is lower. And that means that it will run quieter ar 500hz because of the impedance jump.

Unless you have an amp powerfull enough and can boost the 500hz fader on the EQ a little bit.

On the other hand if we have another 8ohm driver but this one is keeping the 8ohm impedance at 500hz. That driver will run louder at 500hz then the previous one because it will pull more power from the amp?
NO-The amp produces VOLTAGE.  Power is the RESULT of that voltage across a certain impedance load.

If you run a sweep of freq-the output voltage will be the same-NO MATTER what the impedance is.

The POWER will be different because of the different impedances.

You DO NOT boost freq that have a higher impedance.

The impedance has almost nothing to do with the freq response.

You can have points that have a high impedance and they can (but may or may not be) be LOUDER than those with a low impedance-even though there is less "power" going to the driver at those freq.

DO NOT try to put the sensitivity/freq response and the impedance curves together. 

Or to put it another way-if a speaker should "happen" to have flat impedance curve-that DOES NOT mean that the freq response will be flat.  It could vary quite a bit.

A flat impedance curve is no better or worse than one with a lot of peaks.

The impedance curve is the RESULT of the final design-including tuning of the cabinet-crossover design-driver design etc
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 15, 2016, 06:54:58 pm
You didn't understand me.

I realize that the amp just regulates and rises voltage and the power that is going through the coil is determined by the impedance at that moment.

BUT, We have Driver 1 and we have driver 2.

They both have exactly the same sensitivity curve.
They are both rated at the same RMS power.
They are both rated at the same nominal impedane of 4 ohms.
And they are both connected to an amp that shouldn't run under 4ohms and it's power is the same as the RMS power of the driver. So it's slightly underpowered for those drivers.

Now, the only thing that is different between these drivers is that driver 2 stays consistantly around 4 ohms over the entire frequency spectrum but driver 1 has peaks up to 8 ohms at many spots.

This basicaly means that driver 1 will run quieter of this amp generally.
Because it will be using it's power not as much as it could at all frequencies.
If we had a more powerfull amp, we could compensate for drivers impedance jumps by boosting power at frequencies at which the driver has higher impedance. Because if the driver can take 500w rms at all frequencies. And the amp needs let's say a 50v output at four ohms to use all of drivers headroom then if the impedance jumps to 8 ohms the amp needs to rise the voltage in order to use all of the drivers headroom.

So in a way, the impedance graph will have a connection with how loud the driver can get unless you have an overpowered amp and can push it as hard as possible at all frequencies. 
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: g'bye, Dick Rees on February 15, 2016, 06:56:47 pm
You didn't understand me.

I realize that the amp just regulates and rises voltage and the power that is going through the coil is determined by the impedance at that moment.

BUT, We have Driver 1 and we have driver 2.

They both have exactly the same sensitivity curve.
They are both rated at the same RMS power.
They are both rated at the same nominal impedane of 4 ohms.
And they are both connected to an amp that shouldn't run under 4ohms and it's power is the same as the RMS power of the driver. So it's slightly underpowered for those drivers.

Now, the only thing that is different between these drivers is that driver 2 stays consistantly around 4 ohms over the entire frequency spectrum but driver one has peaks up to 8 ohms at many spots.

This basicaly means that driver 1 will run quieter of this amp generally.
Because it will be using it's power not as much as it could at all frequencies.
If we had a more powerfull amp, we could compensate for drivers impedance jumps by boosting power at frequencies at which the driver has higher impedance.

So in a way, the impedance graph will have a connection with how loud the driver can get unless you have an overpowered amp and can push it as hard as possible at all frequencies.

You have quite an imagination.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 15, 2016, 08:59:53 pm
You didn't understand me.

I realize that the amp just regulates and rises voltage and the power that is going through the coil is determined by the impedance at that moment.

BUT, We have Driver 1 and we have driver 2.

They both have exactly the same sensitivity curve.
They are both rated at the same RMS power.
They are both rated at the same nominal impedane of 4 ohms.
And they are both connected to an amp that shouldn't run under 4ohms and it's power is the same as the RMS power of the driver. So it's slightly underpowered for those drivers.

Now, the only thing that is different between these drivers is that driver 2 stays consistantly around 4 ohms over the entire frequency spectrum but driver 1 has peaks up to 8 ohms at many spots.

This basicaly means that driver 1 will run quieter of this amp generally.
Because it will be using it's power not as much as it could at all frequencies.
If we had a more powerfull amp, we could compensate for drivers impedance jumps by boosting power at frequencies at which the driver has higher impedance. Because if the driver can take 500w rms at all frequencies. And the amp needs let's say a 50v output at four ohms to use all of drivers headroom then if the impedance jumps to 8 ohms the amp needs to rise the voltage in order to use all of the drivers headroom.

So in a way, the impedance graph will have a connection with how loud the driver can get unless you have an overpowered amp and can push it as hard as possible at all frequencies.
I really do not know how to respond to this.

There are so many things that are wrong with the "thinking".

You need FORGET about "equal power thing".

If 2 speakers have the same sensitivity TO THE SAME VOLTAGE (Notice I did NOT say power), then they will be the same loudness at all levels.

Who said loudspeakers handle the full power at all freq?

No manufacturer that I know of.

The way the wattage is determined is a noise signal is applied at a certain VOLTAGE (notice no power is mentioned) and they can handle this voltage with no damage.

The power is then CALCULATED using the nominal impedance and the voltage applied.

At freq that the impedance is higher-there will be less power being USED by it. 

It is NOT a good idea to "think" that you can get greater loudness by boosting at the freq at which the impedance is higher.

SURE-you can do that- if LOUDNESS is THE ONLY thing you are interested in.  The sound quality will get all kind of screwed up.

NO measurement system used for freq response measures the power going to a speaker.  They simply look at how loud it is.

If some freq as as loud as others-but only 1/10th the power is going to them-GOOD.

But nobody (almost nobody) ever even thinks about trying to have equal power at all freq.  It is about equal loudness.

I don't know if that helps.

Not to be rude-but you really need to change your way of thinking about this.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: radulescu_paul_mircea on February 16, 2016, 05:37:58 am


You didn't understand me.

I realize that the amp just regulates and rises voltage and the power that is going through the coil is determined by the impedance at that moment.

BUT, We have Driver 1 and we have driver 2.

They both have exactly the same sensitivity curve.
They are both rated at the same RMS power.
They are both rated at the same nominal impedane of 4 ohms.
And they are both connected to an amp that shouldn't run under 4ohms and it's power is the same as the RMS power of the driver. So it's slightly underpowered for those drivers.

Now, the only thing that is different between these drivers is that driver 2 stays consistantly around 4 ohms over the entire frequency spectrum but driver 1 has peaks up to 8 ohms at many spots.

This basicaly means that driver 1 will run quieter of this amp generally.
Because it will be using it's power not as much as it could at all frequencies.
If we had a more powerfull amp, we could compensate for drivers impedance jumps by boosting power at frequencies at which the driver has higher impedance. Because if the driver can take 500w rms at all frequencies. And the amp needs let's say a 50v output at four ohms to use all of drivers headroom then if the impedance jumps to 8 ohms the amp needs to rise the voltage in order to use all of the drivers headroom.

So in a way, the impedance graph will have a connection with how loud the driver can get unless you have an overpowered amp and can push it as hard as possible at all frequencies.

Pfiu! No, as Ivan said, you first have to learn how drivers in speakers work. A driver/speaker has a variable impedance curve Because it is a reactive load. The sensitivity of the speaker is given as the voltage sensitivity in reality. They find out what is the nominal impedance rating in the usefull bandpass, and if it is 8 ohms they teat it with constant 2,83 V, if it is 4 ohms they use 2.0 volts etc. Remember, it is a constant voltage and not constant power. It is the way it works.
So, now, if you have a driver rated 100 db at 1w/meter at 4 ohms, and 1000 watts and another at 100db/w at 8 ohms and 1000 watts, and an amp capable of 1000 watts/8ohms and and another at 1000/4ohms they will both get to max 130 db and no more if you use the correct amp for the correct driver. The difference is that one is rated at a higher voltage than the other.
Now if you would switch the amps and they are both stable at even 2 ohms, then you will see what impedance is doing. The 8ohms driver on the 1000watts/4ohm amp will get only 500 watts Nominal. The other one on the other amp will get 2000watts nominal. One will burn one will be underpowered.
There are current based amplifier, that have constant power at variable frequencies but they have to work with special speakers, designed!!!! to work with that kind of amp. Our speakers and our amps are designed to work with constant voltage. If you know how to play in Hornresp you have the posibility to see what constant voltage and what constant power does to the frequency response of a speaker
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 16, 2016, 06:23:17 am
Okay there seems to be one majour thing i understood completly wrong here and therefore got all these wrong assumptions.

Sensitivity is measured with voltage. If 2 drivers have 100dB sensitivity at 500hz that means that if any of them gets 50 volts at 500hz they will play exactly the same loudness.
BUT if their impedance is not the same at that voltage, one of them will pull more power then the other one.

Okay, that's all quiet clear. BUT again. If they are both capable of handling the same amount of power at 500hz then the one with a lower impedance will be a less capable driver. Because when we give them both the same voltage. The one with a lower impedance is going to be closer to it's thermal limits.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: radulescu_paul_mircea on February 16, 2016, 06:30:17 am


BUT if their impedance is not the same at that voltage, one of them will pull more power then the other one.

Okay, that's all quiet clear. BUT again. If they are both capable of handling the same amount of power at 500hz then the one with a lower impedance will be a less capable driver. Because when we give them both the same voltage. The one with a lower impedance is going to be closer to it's thermal limits.
If you put a sine wave at that freq , yes, you are right. The one with lower impedance will get more amps and heat and will have the same Spl. To the other, ypu could rise the voltage to get the same amps and heat and it will give more spl. You understood correctly
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: radulescu_paul_mircea on February 16, 2016, 06:45:23 am
As another example, if you have a closed sub and it has a liniar resp from 30 hz with a maximum given power and it doesn't reach xmax at max power but it has a rising impedance from 30hz down, one could rise the voltage to get more Spl at those frequencies without risking to burn the coil. So if you apply your theory like this, it is usefull. Also, this is why in subwoofers, horn subs are (not really  a rule) capable of getting not only a better sensitivity but also a better power(read voltage) handlling, because in the bandpass, the impedance is more variable and the average dissipated heat in a music program (not sine wave) will be less at the same voltage.
Also, I see why everybody gets confused qith these terms. It always is the power that is specified in products. This is because most if the time, power is the thing that limits us. But the speakers are made to be linear with a constant voltage and also it will allow a specific maximum heat dissipation.The average power a driver can dissipate, the max power vs time an amp can generate etc. But having more data about impedance curves, , response curves, electric phase curves, specific heat, temperature rise times,max temperatures,  and so forth for the drivers and also more infos about the capabillities of amplifiers(power vs time,  clipping behavior, max voltagevs frequency, thd, imd and so forth) one could create a very high performance system, that would push the limits but never exceeds them.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 16, 2016, 07:08:47 am
Yes, well the point is understanding this teory well so i can use it in reallity.
Many soundguys tell me how pushing subs too low is dangerous because the lower the frequency is the more power a driver will need and lower frequencies will heat up the coil exponentialy more...
But this is a completly wrong statement.
Yes, pushing subs lower then you should might not be a great idea because of some other reasons. But in reality. If i take a good look at the impedance graph of my subwoofer and realise it starts jumping impedance under 40hz but starts dropping impedance between 40 an 60hz. That might mean that my drivers are going to be safer if i push them hard under 40hz and keep them a bit quieter between 50 and 60 then they will be if i lowcut them at 35 and force the hell out of them at 50 and 60hz.

And yes, in order to understand theory i try making my questions and examples in them as simple as possible but i am aware of the amount of factors that i need to be counting on when i try using this in reality.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: radulescu_paul_mircea on February 16, 2016, 07:27:53 am
A subwoofer starts to loose efficiency under Fs so at the -10 point if you need ten times the power to reach the level over fs. So it is not a good thing to do that, they are right. Best case scenario, if some speakers have the impedance rising A Little under F3 so one can get a few hertz extension, and not always linear but with a down curve. Take care
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 16, 2016, 07:35:21 am
Yes, well the point is understanding this teory well so i can use it in reallity.
Many soundguys tell me how pushing subs too low is dangerous because the lower the frequency is the more power a driver will need and lower frequencies will heat up the coil exponentialy more...
But this is a completly wrong statement.
Yes, pushing subs lower then you should might not be a great idea because of some other reasons. But in reality. If i take a good look at the impedance graph of my subwoofer and realise it starts jumping impedance under 40hz but starts dropping impedance between 40 an 60hz. That might mean that my drivers are going to be safer if i push them hard under 40hz and keep them a bit quieter between 50 and 60 then they will be if i lowcut them at 35 and force the hell out of them at 50 and 60hz.

And yes, in order to understand theory i try making my questions and examples in them as simple as possible but i am aware of the amount of factors that i need to be counting on when i try using this in reality.
No freq heats up a driver any more than any other freq-AS LONG AS the impedance of the driver is the same.

At different freq the heating will be different.

Now EXCURSION is a completely different issue.

What the lower peaks on the impedance curve tell you is where the cabinet is tuned.

In a ported cabinet you will see 2 peaks.  If it is properly tuned, they should be equal.  The tuning freq is the freq at the low point between the 2 peaks.

You REALLY REALLY NEED to STOP thinking about how hard you can drive your cabinets based on the impedance.

You should be more focused on the freq response or amplitude of the system.

Unless the ONLY thing that is of interest to you is loudness-no matter what it sounds like.

If you start to "get the most" due to the impedance-you will end up with a very unbalanced sound.

For example-let's say a DJ does a sweep- and you have boosted certain freq due the impedance idea.

Well the sweep is going to louder and quieter at different freq  Is that what you want?  I doubt it. 

But if it makes you feel better to say "Well I am "pushing" the maximum out of the system", then OK .  But people don't care about that-they care about how it sounds-at least most people do.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 16, 2016, 07:55:53 am
Yes i understand there is no more point in pushing the speaker when it hits anything above a -6dB drop in sensitivity. I didn't say i should push subs lower then they can go in reality. But i shouldn't push them from different reasons. Not from a reason that lower frequencies heat up the coil more. As Ivan said, the amout of heat a coil generates depends only on the amount of power going through it and the resistance that the coil makes. Or in the other words heat depends on the voltage the amp is giving it and the impedance of the coil at a certain frequency.

Ivan:
How are impedance variatons related to how a cabinet affects the driver? The impedance of a coil depends on the material that the coil is made of (copper) and the number of windings.
Shouldn't the impedance/frequency graph be the same if the driver is in open air vs any kind of box?
Or... shouldn't it be the same even if we just have the coil itself out of the driver completly. Why does the way coil "moves" at a certain frequency affect it's impedance.  What am i missing?

Yes if i start trying to get the most out of the system based on impedance it will sound unbalanced BUT if i know how and where i can get more... then i can tune the system better. I won't boost a certain area just because the driver can take more in that area. But if it drops sensitivity 3dB from 30 to 25hz and i know i can push it more in that area. Then i will, and it's response is going to get a bit flatter from 30 to 25hz
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Art Welter on February 16, 2016, 11:39:37 am
1)Shouldn't the impedance/frequency graph be the same if the driver is in open air vs any kind of box?
Or... shouldn't it be the same even if we just have the coil itself out of the driver completly. Why does the way coil "moves" at a certain frequency affect it's impedance.  What am i missing?

2)Yes if i start trying to get the most out of the system based on impedance it will sound unbalanced BUT if i know how and where i can get more... then i can tune the system better. I won't boost a certain area just because the driver can take more in that area. But if it drops sensitivity 3dB from 30 to 25hz and i know i can push it more in that area. Then i will, and it's response is going to get a bit flatter from 30 to 25hz
1) The DCR (direct current resistance, what you measure with an ohmmeter) of a voice coil will be the same regardless of it being in or out of a box. In a box, the resistance becomes impedance, and different boxes have different impedance transforms, which is why the impedance curve is different for different designs. Most designs will have an impedance minima very close to or equal to the DCR.

2) You seem to have already forgot that there are two failure modes in a speaker- thermal and mechanical. When you drive your speakers below Fb, (you obviously skipped measuring their Fb, which is probably around 45 Hz) the power is wasted, and the excursion rises rapidly (you would have seen that if you measured it) increasing the muddy sound you complain of, and potentially will tear the cone, surround, or spider, or hammer the voice coil on the back plate if the driver is given enough voltage. Below Fb, it takes very little voltage to exceed Xmax in a bass reflex enclosure.

Art
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: radulescu_paul_mircea on February 16, 2016, 12:54:17 pm
The direct current resistence or DCR of a wire is a propriety of the material and varies only with wire thickness and temperature.
This resistance will be different and will vary with alternative or changing current because of many reasons. The whole amount of factors inclusive wire resistance will impede the flow off current and there is the term "impedance" comming from. You should search about this on the net or books.
In a voice coil in free air wirh a constant temperature the wire has a fixed DCR equal with the declaired RE in Thiele small parameters. When you apply alternative current this coil of wire will have a constant impedance rise as you go higher and higher in frequency because of a thing called skin effect but that starts at a Very high frequency.
If you put the coil inside a magnet system coupled with a diaphragm, suspensio, moving parts, magnetic fields, eddy currents etc the impedance will be very different than the DCR and it will have a resonant frequency where all those factors will sum. If you then put that driver in a closed enclosure you will change some of the mechanical properties of that system and the impedance will be different but it will still have only one resonant frequency. If you put it in a bass reflex you change it more, in a horn even more, add many drivers in a 4 way system, also the crossover components, the wires, interferences, amplifier behavior and you will understand why the impedance curve is not a simple number.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 16, 2016, 05:55:21 pm

Ivan:
How are impedance variatons related to how a cabinet affects the driver? The impedance of a coil depends on the material that the coil is made of (copper) and the number of windings.
Shouldn't the impedance/frequency graph be the same if the driver is in open air vs any kind of box?

No-the box can greatly affect the impedance or the loading of the driver to the air.

In fact-you can take a HF driver and set a constant tone impedance meter in the HF range and move your hands above and around the exit (the driver is not on a horn at this time) and watch the impedance change with your hand movements.

There is a lot to be learned from the impedance curve in terms of how the driver is "loaded" to the air.

This is why certain sub designs can actually double the rated impedance of the driver-due to the loading.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Stephen Kirby on February 17, 2016, 01:40:44 am
Maybe download WinISD and model your Yamaha boxes.  The Eminence T/S parameters should be in there and you can just start with the approximate dimensions you can see.  Now look at the impedance curve and note where fb and fs are relative to that.  Start playing with the port dimensions to try and get the box to play lower.  Now watch what happens with the impedance graph and the xmax excursion graph.  That may help you envision the interrelationship between the box tuning, the impedance curve and the driver excursion.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 17, 2016, 06:18:38 am
Yes but i wanted to know why this happens. Then a friend reminded me of some basic electrotechics from school.
Whenever the coil is moving in the magnet gap there is going to be electricity induced back in the coil, by the magnet. This electricity will create resistance to the electricity the amp is pushing to the coil.
I think it's called Lenz's law.
Which means a simple thing. Change the way the coil moves in the magnet gap (put the driver in a drifferent box for an example). And you changed the way that magnet induces electricity in the coil.
In the other words, you changed the coils impedance.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 17, 2016, 06:28:47 am
Also, we did some preparations for the party this friday.
Tried out a cardioid array. Runs like shit in a closed room, just as we expected.

Here:
http://i30.photobucket.com/albums/c316/athlon-64/IMG_4220_zpscobjps2x.jpg

You get cancelation in a relatively big spot behind the subs. When you get close to the walls there is just chaos you can not fix. And outside, in front of the subs, this setup brings nothing good.

So we put them down in a standard mono block:

http://i30.photobucket.com/albums/c316/athlon-64/IMG_4222_zpsuoq4s41z.jpg

http://i30.photobucket.com/albums/c316/athlon-64/IMG_4223_zps6n1oovpn.jpg

And i realised they work quiet a lot better like this. When you are standing in front of the stage you are in the power alley of the subs so you hear them, not the room. I hooked them up to my peecker sound amps with shorts cables. Did some tests and even felt the transients, hits of short sub on top of basslines. Quiet a bit better then usual it seems to me. Maybe it's just mostly about the room. When ther are left and right the simple problem is. Wherever you are (unless you are in front of the boxes) you hear sub chaosing around from the room. You don't hear much directly from the boxes. But in a mono block like this everyone in front of the stage feels more from the subs then from the room.

I also tried a compressor trick that seems to work. A friend explained me this a few days ago:
Insert a compressor on the matrix of the subwoofers. Make the transients an peaks activate it, when they do, make it compress everything hard but with a slow attack tome so the transients pass.

What happens when i do this is quiet much... the short hits of sub stay untouched while the subline gets quieter. I liked it a lot because these sublines can overload the room, things start shaking and making a lot of noise. All of that sub just sums into a big mess of mud because it has nowhere to go. So the compressor gets that part a bit quieter. But leaves me those peaks and transients where i need them. This gives me a more dynamic less muddy sound from the subs.

Also we realised we have a dead 18. Just one of them in one of the boxes.
Who knows when this happend. It might be months/years old. I'm not the only one running the system so again, who knows who this happened to.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 17, 2016, 12:09:52 pm

I also tried a compressor trick that seems to work. A friend explained me this a few days ago:
Insert a compressor on the matrix of the subwoofers. Make the transients an peaks activate it, when they do, make it compress everything hard but with a slow attack tome so the transients pass.


THat is the same thing as a "thermal" limiter.  With an attack time of around 3 seconds all the transients pass fine (which do not cause heating of the voice coil), but the long term power (which overheats the coils) is limited to around 1/4 to 1/2 the continuous rating of the driver.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 17, 2016, 05:25:38 pm
THat is the same thing as a "thermal" limiter.  With an attack time of around 3 seconds all the transients pass fine (which do not cause heating of the voice coil), but the long term power (which overheats the coils) is limited to around 1/4 to 1/2 the continuous rating of the driver.

Yes, so it's good for the driver and it's a way to slightly accentuate transients
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 17, 2016, 07:22:05 pm
Yes, so it's good for the driver and it's a way to slightly accentuate transients
The problem I see with trying to use this as you describe is that now YOU are affecting the sound the artist is trying to project to the audience.

The sound system should simply make their sound louder and not change the sound.

If the artist WANTED it that way-they would record it that way.  But you are changing their sound on purpose.

Now, when used as protection to keep the loudspeakers from being damaged-that is a totally different thing.

Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 18, 2016, 04:58:07 am
The problem I see with trying to use this as you describe is that now YOU are affecting the sound the artist is trying to project to the audience.

The sound system should simply make their sound louder and not change the sound.

If the artist WANTED it that way-they would record it that way.  But you are changing their sound on purpose.

Now, when used as protection to keep the loudspeakers from being damaged-that is a totally different thing.

No, the soundsystem itself because it's not that good, and the room, because it's terrible, are changing the sound of what the artist had in mind. Then my job is to use all the tools i have to get it as close as the soundsystem can get it back to the original.
I try my best to know the music i'm working with that night. I listen to it before on a pair of monitors. Also i use music very familiar to me when i'm soundchecking and i know this system won't push it out nearely the way it should.
I'm not making the transient stand out more then it should. I'm just making sure it stands out like it should if i can because the combination of yamaha subs and the room would destoy and drown it.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Ivan Beaver on February 18, 2016, 07:30:35 am
No, the soundsystem itself because it's not that good, and the room, because it's terrible, are changing the sound of what the artist had in mind. Then my job is to use all the tools i have to get it as close as the soundsystem can get it back to the original.
I try my best to know the music i'm working with that night. I listen to it before on a pair of monitors. Also i use music very familiar to me when i'm soundchecking and i know this system won't push it out nearely the way it should.
I'm not making the transient stand out more then it should. I'm just making sure it stands out like it should if i can because the combination of yamaha subs and the room would destoy and drown it.
As long as it works for you and your customer.

But you made it sound like it was a good idea for everybody to use-since it was considered a "trick", and not a "tool" for just your room.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 18, 2016, 08:17:02 am
As long as it works for you and your customer.

But you made it sound like it was a good idea for everybody to use-since it was considered a "trick", and not a "tool" for just your room.

Yes i wrote it the slightly wrong way. With a good system and a good room this would only be deforming the music for no reason. Here the situation is different.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Stephen Kirby on February 18, 2016, 01:05:46 pm
The problem I see with trying to use this as you describe is that now YOU are affecting the sound the artist is trying to project to the audience.

The sound system should simply make their sound louder and not change the sound.

Can you post this on the main board?  You've just described almost every soundperson I've worked with in my muso life.   ;D
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Tim McCulloch on February 18, 2016, 11:21:20 pm
Can you post this on the main board?  You've just described almost every soundperson I've worked with in my muso life.   ;D

I'll derail this thread.  Blame me 8)

When I was the BE what I was hired to do varied with the act.  It ranged from "sound like the record" to "sound like the record, LIVE!" to "we do it live like THIS, so forget the record and pay attention".  The middle choice is where my personal taste was give more berth but was still subject to the bands desired presentation.  It took a lot of will power to not over produce when I was young, today as a system guy that mixes openers I find I tend to a more minimalist hand unless I've had a good chat with the artist.

It's a delight to get good direction from an act regarding tonality, musical parts balance, effects, and overall vibe.  These days I've got them for 30 - 45 minutes.  I try to give them what they want and stay out of the way, musically.
Title: Re: Cardioid array in a 800ppl club. Possible options?
Post by: Eugen Jeličić on February 19, 2016, 07:18:33 am
Honestly i believe that as long as a band is relatively educated and knows what they want you should give them only that and not what you think is better. That is yours job. If something can not be done then you need to spend the time to explain why can't it be done. If you are touring with a band of course. When you are working in clubs or festivals with multiple small bands this is almost impossible.

The other thing is, i don't think you realise up to which extend the room i'm working in is acousticaly terrible. This is one of those places where you are happy if all instruments can be recognized withouth getting yours head chopped of. You don't bother with the small detalis like colour of the mix, you fight with getting everything out without drowning everything else.
Things like all guitars having a side chanied compressor triggered by the vocal so you can hear the vocal at all are normal here.
Guy is cupping the mic, this is the second time he is on stage. You are running 3 bearely working yamaha monitors and can't give him any stage level. The room is a huge concrete basement that can fit 900ppl, you only have 80 on the concert. There is more reverb then in a 4km tunnel. You have very little gain before feedback. You had to ring out the monitors AND the PA because od this. You don't bother with details here.
When i'm doing parties i try as much as i can to try and get the song as close as possible to what it sounds like on a pair of monitors but this is not really very possible. You can't get a yamaha club series system at a 110dB in a more the half-empty huge concrete basement to be comfortable for listening unless you dich 1-5k area for even up to -5dB in the worst spots.
Of course, this depends on the music itself, sometimes you have minimal techno with very little elements up there so you don't have to do this.
And the amount of people + humidity + temperature affects this a lot. So i do changes during the party all the time.