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Author Topic: Cardioid array in a 800ppl club. Possible options?  (Read 24795 times)

Eugen Jeličić

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #10 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?
« Last Edit: February 03, 2016, 05:18:01 pm by Eugen Jeličić »
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Ivan Beaver

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #11 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.
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Ivan Beaver
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Ivan Beaver

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #12 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.
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Eugen Jeličić

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #13 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. 

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Eugen Jeličić

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #14 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.
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Lee Wright

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #15 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.
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Ivan Beaver

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #16 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.
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Ivan Beaver
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Ivan Beaver

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #17 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.

« Last Edit: February 03, 2016, 07:18:24 pm by Ivan Beaver »
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Len Zenith Jr

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #18 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.
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Eugen Jeličić

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Re: Cardioid array in a 800ppl club. Possible options?
« Reply #19 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.
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