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Title: How do you calculate PA size?
Post by: Robert Piascik on August 07, 2014, 11:30:11 PM
I am mostly a LabLounger but recently am getting some calls to provide for larger events and I want to supply (or rent) the correct thing. How do you (or can you) calculate what a PA set up is capable of delivering (SPL) at a particular distance?

I have a rider calling for 118dB at the mix position 80-100 ft. from stage. I realize that is vague, but if I have top speakers that can deliver 130 dB peak and 124 dB continuous, how do I know if that is enough or not enough? What if I had two per side? How about four per side?
If the subs can deliver 140 dB peak and 134 dB continuous, how is that going to factor into the equation? How would it be different if speakers were a line array? How would you know how many to hang? Does the speaker sensitivity factor into the calculations as well?

Thanks for any advice.

Title: Re: How do you calculate PA size?
Post by: Cailen Waddell on August 07, 2014, 11:41:37 PM
Outside, sound decreases at about 6db for every doubling of distance.  So if your speakers output is 124 DB at 1m, then at 2 it is 118, at 4 112, at 8, 94, and at 16 meters, 88.

Now that's assuming the numbers you are using and have provided by the manufacturers are accurate and helpful.  If your subs peak output is 140 dB but It can only do that at 500 hz - how is that number helpful. 

Most of the big boys use modeling software to predict peak output.  For line arrays, and trap boxes.  That software will help you know how many boxes you need

There are some far better educated people than me here who can get more specific.

Doing the reverse math 118 at mix is 124 at 50', 130 at 25, 136 at 12.5, and 142 at 6.25, and 148 at 3.125', or about 1 meter.  That's 18db greater than the peak output of your boxes, IF the number from the manufacturer is accurate.  That's a big difference.  When you start to get into dealing with riser acceptable gear, and meetig riders, I find it best to forward the rider to the company you are renting from and ask what they would recommend. 
Title: Re: How do you calculate PA size?
Post by: Tim McCulloch on August 08, 2014, 12:09:25 AM
I am mostly a LabLounger but recently am getting some calls to provide for larger events and I want to supply (or rent) the correct thing. How do you (or can you) calculate what a PA set up is capable of delivering (SPL) at a particular distance?

I have a rider calling for 118dB at the mix position 80-100 ft. from stage. I realize that is vague, but if I have top speakers that can deliver 130 dB peak and 124 dB continuous, how do I know if that is enough or not enough? What if I had two per side? How about four per side?
If the subs can deliver 140 dB peak and 134 dB continuous, how is that going to factor into the equation? How would it be different if speakers were a line array? How would you know how many to hang? Does the speaker sensitivity factor into the calculations as well?

Thanks for any advice.

Was the required 118dB A weighted, C weighted or flat?  Slow or fast response?  Realize that this "spec" is also probably copy and paste bullshit from some other bands rider from 20 years ago...

That said, 102dBA, slow, is loud enough that you'll need to holler to be heard by someone 4 feet away, and 110dBA will require you to shout at a person 1' foot from you.  Set up your rig and play the band's recording, turn it up until you run out of PA, begin to worry about the rig's safety or the police show up (or something breaks).  Use your trusty Radio Shack SPL meter (not a phone, seriously) to measure.

PM me with the name of the act and I'll tell you what I know about them, if anything.
Title: Re: How do you calculate PA size?
Post by: Mark Cadwallader on August 08, 2014, 12:30:02 AM
A not-too-serious way to meet an unreasonable spec:  set up a remote speaker (suitably delayed, of course) 2 meters in front of the mix position. If somebody insists on a stupid requirement, they should expect a stupid solution to meet the requirement.

Please note that I don't really suggest that as a solution -- it is just what I wish I could do under those circumstances. Mark C.
Title: Re: How do you calculate PA size?
Post by: Tim McCulloch on August 08, 2014, 01:18:30 AM
A not-too-serious way to meet an unreasonable spec:  set up a remote speaker (suitably delayed, of course) 2 meters in front of the mix position. If somebody insists on a stupid requirement, they should expect a stupid solution to meet the requirement.

Please note that I don't really suggest that as a solution -- it is just what I wish I could do under those circumstances. Mark C.

The other helpful possibility is moving the mix position closer to the stage, say 70' instead of 100' (you don't want to schlep a console up into the grandstand anyway).  While not 6dB worth of movement, if you're on the edge every little bit helps.
Title: Re: How do you calculate PA size?
Post by: Scott Holtzman on August 08, 2014, 01:22:15 AM
A not-too-serious way to meet an unreasonable spec:  set up a remote speaker (suitably delayed, of course) 2 meters in front of the mix position. If somebody insists on a stupid requirement, they should expect a stupid solution to meet the requirement.

Please note that I don't really suggest that as a solution -- it is just what I wish I could do under those circumstances. Mark C.

True story I am at dinner with a prospect.  He has some of his team with him.  I was in the SE role, our regional sales director and some engineers and other folks from the vendor.

One of the engineers from the vendor was enjoying his wine at a good clip.  He never had much patience with stupid questions.  The client asks this guy how big a router do you think we need.  This guy swills another drink, looks at the client and asks him "how big a router can you fit up your ass?" the sales guys look like stone and the engineer follows up with, it's as good a criteria as any when you don't give me any f***ing data.

Classic

Title: Re: How do you calculate PA size?
Post by: Brian Jojade on August 08, 2014, 11:40:06 AM
I have a rider calling for 118dB at the mix position 80-100 ft. from stage. I realize that is vague, but if I have top speakers that can deliver 130 dB peak and 124 dB continuous

First off, 118dB at the mix position 100 ft out is friggin loud.  I feel for anyone that is positioned between the stage and FOH.  Provide plenty of cotton balls to soak up the blood from their ears. Just stating that they want 118dB tells me that the rider is just as good as toilet paper, but not as soft.  It probably says they want a frequency response of 20Hz-20kHz too, right?


Secondly, using the listed spec of 130dB peak and 124dB continuous is just reading the marketing bullshit that you are seeing on the speaker spec sheet.  Good luck getting those results real world.  Adding MORE speakers per side will just garble your sound.  If the speaker isn't up to the task, more of them won't help.

For sizing the gear appropriately, you need to provide WAY more information than you have.  What's the venue in question?  If you're in a narrow bar with low ceilings and FOH is just at the back of the bar, that's very different than if you're in a football stadium that holds 20,000 people.

At the very minimum, when discussing a sound system, you will need to know the following.

1. Size of the venue being covered. The rough room dimensions will work.
2. Type of room - i.e., a theater, metal shed, tent, outdoors, etc. Each will have their own requirements to make sound work correctly.
3. How much of the venue you want filled with sound.  Depending on the event, they may not want even coverage for the whole room.
4. What type of music/speech are you playing?  An acoustic set will need far less PA than a grunge metal system.

Title: Re: How do you calculate PA size?
Post by: Roland Clarke on August 08, 2014, 06:24:18 PM
Firstly a ready reckoner is that sound drops off at around 6db a doubling of distance as a previous poster mentioned,  This changes to about 3db a doubling of distance if you are using a line array. Stuff like Ease is great for prediction, we had a very prominent noise consulting firm working on the particular project I did recently and they did some very detailed modelling, including buildings and other structures that came into the equation and my ready reckoner that I did in my head was within 1db of their model.  The most interesting thing was that on the event day the actual readings were within 1db of the modeled version.  Manufacturers are notorious for providing less than candid performance figures for their gear, however, most quality modern boxes are capable of making a lot of noise.  Knowing the rigs you use, and what they can do in real terms is a must in this game.  Many tours go out with a lot more boxes than they need, regional suppliers make their money by cutting it much closer and by consequence providing a more cost effective solution.  The good small suppliers do this successfully, the rubbish ones don't.
Title: Re: How do you calculate PA size?
Post by: Ivan Beaver on August 08, 2014, 07:46:08 PM
Firstly a ready reckoner is that sound drops off at around 6db a doubling of distance as a previous poster mentioned,  This changes to about 3db a doubling of distance if you are using a line array.
Not in the real world. 

Maybe at some freq and the right position-but certainly not at a wide range of freq and at different points in the array.

That is just another "myth" that the marketing departments like.
Title: Re: How do you calculate PA size?
Post by: Ivan Beaver on August 08, 2014, 07:58:12 PM
Just to add to the other comments, when looking at models or trying to use specs to determine the loudness you have to consider the following.

To get the peak SPL-you have to have an amp that is rated at the peak wattage of the speaker.  Most people do not use amps that are rated that high-so the peak SPL is not realizable.

DO NOT assume that the amp will automatically produce additional level above it rated wattage.

Years ago amps were rated different.  They were rated at sine wave output and could produce peaks that were A LITTLE BIT (NOT 6dB) higher than the rated wattage-for a very short period of time.

Today amps are rated WITH THOSE PEAKS-so no additional power can be assumed.

Also you have to consider the dynamic range of music.  Most music is between 10 and 20dB.

So if the peak output is 130dB peak and the music has a 20dB dynamic range, then the "average" or what people would typically read on an SPL meter is 110dB.  NOT 130dB.

Sub levels are typically MUCH hotter than the mains.  This can range from as little as 10dB to as much as 30dB hotter.  I would say 15-20dB is "fairly normal".

So if the tops are capable of 130dB, then the subs should be capable of 150dB.

Now this can vary depending on the situation.  Inside you can get some benefits of room gain-so less "calculated" sub output can be used.

But outside there is no room gain-so you need to typically plan on at least twice as much sub-if not 4 times as what you would use indoors.

If you simply double the full range cabinets-you will get "some" increase in level.  At the lower freq this could be as much as 6dB.  But at other freq where there is cancellation due to different arrival times at a particular listening position the actual output will be LOWER.  But there will be freq higher and lower that will actually be a little bit louder.

So the "overall" level will appear to be louder-but the sonic quality will be lower-WITH ANY LOUDSPEAKER BY ANY MANUFACTURER.

How much will it be affected?  It depends on a lot of factors of the loudspeaker design-how it is deployed and so forth.

As as usual-there is no "simple" answer.  It depends on what sort of answer you are looking for.
Title: Re: How do you calculate PA size?
Post by: g'bye, Dick Rees on August 08, 2014, 08:03:17 PM
I suspect that the seemingly "inflated" SPL spec may in fact be asking for a system with enough headroom so that hitting, say, 110dBc at FOH will not be running the system flat out...requiring the BE's to "mix down" on a marginal system on the edge of component failure.

I have assisted several local festivals in getting established, going through the various stages of SOS, trap cabs on scaffold, dual PA, etc until they got big enough (and experienced enough) to see the value in hiring an outfit with enough rig for the gig. 

Now they get "thicker" sound and happier band engineers who no longer have to pull out all the stops just to get close to the levels they need.
Title: Re: How do you calculate PA size?
Post by: Charlie Zureki on August 08, 2014, 09:37:48 PM
I suspect that the seemingly "inflated" SPL spec may in fact be asking for a system with enough headroom so that hitting, say, 110dBc at FOH will not be running the system flat out...requiring the BE's to "mix down" on a marginal system on the edge of component failure.

I have assisted several local festivals in getting established, going through the various stages of SOS, trap cabs on scaffold, dual PA, etc until they got big enough (and experienced enough) to see the value in hiring an outfit with enough rig for the gig. 

Now they get "thicker" sound and happier band engineers who no longer have to pull out all the stops just to get close to the levels they need.


   +1


  Hammer
Title: Re: How do you calculate PA size?
Post by: g'bye, Dick Rees on August 08, 2014, 10:08:27 PM
Hi, Charlie.  Hope all's well.

DR
Title: Re: How do you calculate PA size?
Post by: Robert Piascik on August 08, 2014, 10:45:23 PM
Was the required 118dB A weighted, C weighted or flat?  Slow or fast response?

Of course this info wasn't specified, so we all know this is not specific enough to be useful. Dick had a good point in that it just may mean that they don't want 110dB to be straining the system (just as spec-ing a 40 ch console when there are only 22 inputs is designed to keep out the bottom feeders).

The venue is a county fairgrounds grandstand 250' wide but only 100' deep with the stage on the track right up against the fence so audience will need nearly 180 degrees coverage. I can't imagine that we would place FOH at 80'-100' from the stage given those dimensions. Music is a Southern rock band you have heard of.

My initial idea was to fly DSL SH46 two per side facing front with two SM80 per side (also flown) for side fills because that's what's readily available, but have no idea if that will be:
1) plenty
2) enough
3) not enough
4) not even close

Eight Danley TH-118 subs, everything powered by iT8K one box per ch

You can all chime in on why this is a good or bad idea, and for the size events I usually do that seems like a screaming PA, but in a theoretical sense how would you know what is 'big enough' and what is not?

I come to this forum to learn from guys that are waaaay smarter and more experienced at this stuff than me. Thanks in advance for any advice you can offer.

Title: Re: How do you calculate PA size?
Post by: Rick Powell on August 09, 2014, 05:32:14 AM
Of course this info wasn't specified, so we all know this is not specific enough to be useful. Dick had a good point in that it just may mean that they don't want 110dB to be straining the system (just as spec-ing a 40 ch console when there are only 22 inputs is designed to keep out the bottom feeders).

The venue is a county fairgrounds grandstand 250' wide but only 100' deep with the stage on the track right up against the fence so audience will need nearly 180 degrees coverage. I can't imagine that we would place FOH at 80'-100' from the stage given those dimensions. Music is a Southern rock band you have heard of.

My initial idea was to fly DSL SH46 two per side facing front with two SM80 per side (also flown) for side fills because that's what's readily available, but have no idea if that will be:
1) plenty
2) enough
3) not enough
4) not even close

Eight Danley TH-118 subs, everything powered by iT8K one box per ch

You can all chime in on why this is a good or bad idea, and for the size events I usually do that seems like a screaming PA, but in a theoretical sense how would you know what is 'big enough' and what is not?

I come to this forum to learn from guys that are waaaay smarter and more experienced at this stuff than me. Thanks in advance for any advice you can offer.

You should be able to hit 108-110 dB easily at 100 feet from the stage with that system, provided the tops also have about 2k watts per speaker available.  Coverage wise, the SH series drop off pretty sharply outside their pattern, so I don't see you having 180 "true" degrees of inside the pattern coverage.  Using the SM80s for front fill might allow you to splay the 46s a little to the outside, so you may get acceptable coverage for most of your audience.
Title: Re: How do you calculate PA size?
Post by: Jonathan Betts on August 09, 2014, 09:52:05 AM
FWIW, I have been running 4 TH 118/ 2 SM 80. Testing with a Radio Shack meter for soundchecks,  I can  hit 110dbc slow response at 80' with about 10db of headroom.

This sounds like a killer setup. Let us know how it goes!
Title: Re: How do you calculate PA size?
Post by: Ivan Beaver on August 09, 2014, 10:49:14 AM
.

The venue is a county fairgrounds grandstand 250' wide but only 100' deep with the stage on the track right up against the fence so audience will need nearly 180 degrees coverage. I can't imagine that we would place FOH at 80'-100' from the stage given those dimensions. Music is a Southern rock band you have heard of.

My initial idea was to fly DSL SH46 two per side facing front with two SM80 per side (also flown) for side fills because that's what's readily available, but have no idea if that will be:
1) plenty
2) enough
3) not enough
4) not even close

Eight Danley TH-118 subs, everything powered by iT8K one box per ch

You can all chime in on why this is a good or bad idea, and for the size events I usually do that seems like a screaming PA, but in a theoretical sense how would you know what is 'big enough' and what is not?

I come to this forum to learn from guys that are waaaay smarter and more experienced at this stuff than me. Thanks in advance for any advice you can offer.

As stated earlier-the first step would be to do a model.  So if you use the Danley DIRECT-a free program for PC and MAC
  http://www.danleysoundlabs.com/support/ddt-files/

you could end up with something like below.  This is assuming the speakers are 40' apart with the SH46s flown at 20' and pointed towards the outside corners.

The SM80s are pointed inwards.  The TH118s are stacked in a block of 4 under each speaker system.  Of course a different sub configuration could be used.

I choose this layout to give the most even coverage. If you wanted the most SPL in the middle you could aim the SH46s inwards and have the SM80s towards the outside.  It depends on what is most important to you.

Some of the mic colors are as follows.  The RED is FOH ( I put it 80' out in the middle.)

The LIGHT BLUE is in the middle 20' from the stage and the green is in a far outside corner.

The other mics are kinda inbetween those locations.  You can add a lot more if you wish-but this is just a starting point.

I also did not spend any real time aiming or aligning the speakers-they are just put in and playing.  So the response could be a bit better if time was spent in that area.

But it gives a good indicator of what sort of PEAK SPLs and freq response you would be looking at.
Title: Re: How do you calculate PA size?
Post by: Roland Clarke on August 09, 2014, 06:27:33 PM
Not in the real world. 

Maybe at some freq and the right position-but certainly not at a wide range of freq and at different points in the array.

That is just another "myth" that the marketing departments like.

In more detailed terms when you start looking at lobbing and cancellations, yes, but all systems, even trap boxes suffer from this.  I understand that your boxes avoid these problems because of their "unique" design, but then you are falling off at a standard 6db per doubling and as discussed in the other thread, whilst possible an ideal situation in an install where the system can be uniquely tailored to the room, more often than not, the rigors of touring or single hit dates doesn't allow this level of customisation and jobs have to be worked out using what is "on the trucks".

I'm not the greatest fan of line array's for all the reasons you have mentioned here and on other thread's, however, possibly their best attribute is the ability to cover fairly deep venues with a pretty good average SPL.  Forgetting the comb filtering aspect, close to 3-4db per doubling is achievable when measured on a A weighted leq 15 reading.  How good you or anyone else feel's it sounds is another subjective matter.

All this being said, as you pointed out, it depends on so many other factors, many of which have nothing to do with delivering the best sound solution.
Title: Re: How do you calculate PA size?
Post by: Ivan Beaver on August 09, 2014, 07:15:19 PM
In more detailed terms when you start looking at lobbing and cancellations, yes, but all systems, even trap boxes suffer from this.  I understand that your boxes avoid these problems because of their "unique" design, but then you are falling off at a standard 6db per doubling and as discussed in the other thread, whilst possible an ideal situation in an install where the system can be uniquely tailored to the room, more often than not, the rigors of touring or single hit dates doesn't allow this level of customisation and jobs have to be worked out using what is "on the trucks".

I'm not the greatest fan of line array's for all the reasons you have mentioned here and on other thread's, however, possibly their best attribute is the ability to cover fairly deep venues with a pretty good average SPL.  Forgetting the comb filtering aspect, close to 3-4db per doubling is achievable when measured on a A weighted leq 15 reading.  How good you or anyone else feel's it sounds is another subjective matter.

All this being said, as you pointed out, it depends on so many other factors, many of which have nothing to do with delivering the best sound solution.
One of the big 'misunderstandings" is that "non line array" systems cannot deliver even freq/SPL front to back.

It is not hard at all-it just takes proper knowledge and design.

I have done many hundreds of systems that it is the same level at the front as it is at the back-WITH the same freq response!!!!!

Simply measuring with a SPL meter is pretty worthless in terms of saying it is the same SPL.

It gives "a number" but does not actually prove anything-at least anything worthwhile.  You HAVE to look at the actual freq response to get anything meaningful.

We had a local church that was getting several hundred WRITTEN complaints about the system each week.  NOT our install.

We went in and measured lots of places in which there were really wide holes that were 25dB deep.  NOT good.

The system was a VERY FAMOUS brand (and expensive) that would meet any rider-so no problems there.

So the manufacturer was brought in and they measured the room and told the Church that the system was +/-4dB-within the installers specs.

When I found out about this I said BS and asked for some data.  So they provided it-or at least what they "called data".

It was a graph that had SPL on the vertical axis and a hundred or so seats on the horizontal axis.

They were all within +-4dB.

HOWEVER if you actually measured THE RESPONSE in the room, you would find out that at 118Hz the system had a hump that was around 20dB louder than the rest of the freq response.

So the simple SPL meter was reading that hump and they just chose to ignore the rest of the response.

So we went in and did not sell the church anything except a couple of days labor-rehung the existing system and GAVE THEM BACK about $40,000 worth of speakers that I did not want in our redo.

The complaints went to zero.  At least until they got a new sound guy and he brought in an "expert" to retune the system and then the complaints started again--------

Using the wrong tool is not good-but it was all they could come up with so as not to embarrass their local "golden boy" who was installing lots of their gear.

For what it is worth-I redid (using existing gear-just rehanging it) 3 of their systems and the customers were much happier with the gear used the correct way-at least within the limitations of the existing products.
Title: Re: How do you calculate PA size?
Post by: Roland Clarke on August 11, 2014, 06:01:28 PM
One of the big 'misunderstandings" is that "non line array" systems cannot deliver even freq/SPL front to back.

It is not hard at all-it just takes proper knowledge and design.

I have done many hundreds of systems that it is the same level at the front as it is at the back-WITH the same freq response!!!!!

Simply measuring with a SPL meter is pretty worthless in terms of saying it is the same SPL.

It gives "a number" but does not actually prove anything-at least anything worthwhile.  You HAVE to look at the actual freq response to get anything meaningful.

We had a local church that was getting several hundred WRITTEN complaints about the system each week.  NOT our install.

We went in and measured lots of places in which there were really wide holes that were 25dB deep.  NOT good.

The system was a VERY FAMOUS brand (and expensive) that would meet any rider-so no problems there.

So the manufacturer was brought in and they measured the room and told the Church that the system was +/-4dB-within the installers specs.

When I found out about this I said BS and asked for some data.  So they provided it-or at least what they "called data".

It was a graph that had SPL on the vertical axis and a hundred or so seats on the horizontal axis.

They were all within +-4dB.

HOWEVER if you actually measured THE RESPONSE in the room, you would find out that at 118Hz the system had a hump that was around 20dB louder than the rest of the freq response.

So the simple SPL meter was reading that hump and they just chose to ignore the rest of the response.

So we went in and did not sell the church anything except a couple of days labor-rehung the existing system and GAVE THEM BACK about $40,000 worth of speakers that I did not want in our redo.

The complaints went to zero.  At least until they got a new sound guy and he brought in an "expert" to retune the system and then the complaints started again--------

Using the wrong tool is not good-but it was all they could come up with so as not to embarrass their local "golden boy" who was installing lots of their gear.

For what it is worth-I redid (using existing gear-just rehanging it) 3 of their systems and the customers were much happier with the gear used the correct way-at least within the limitations of the existing products.

I'm not a great lover of "in room response" as it can be way off wack and can measure very different from the way our ears actually perceive sound.  I believe one of the things that Smaart talk about at their seminars is the need to measure the system almost as if it isn't in the room.  Room response is often subject to standing waves, reflections, that do not necessarily impact on how we perceive the "source" sound.  A classic example of this for me would be that of an orchestra playing, short of acoustic treatment the sound good or bad is only a result of the room and there is little that can be done to resolve these issues, short of positioning and aiming.

I don't argue that non line array systems can (given specialised design), give even coverage front to back and side to side, but this will require a specialist install and multiple differing "box" elements, most line arrays are travelling as 1 bass box 1 top box (given that they often have two dispersion widths) and a number of infills.

At a time when there are (in my personal veiw) maybe not so many "great" engineers about, the reality is that the average standard of concert sound these days is significantly better than it was 10-20 years ago and this is all down to the improvement in kit, particularly speakers.
Title: Re: How do you calculate PA size?
Post by: Ivan Beaver on August 11, 2014, 07:19:02 PM


I don't argue that non line array systems can (given specialised design), give even coverage front to back and side to side, but this will require a specialist install and multiple differing "box" elements, most line arrays are travelling as 1 bass box 1 top box (given that they often have two dispersion widths) and a number of infills.

At a time when there are (in my personal veiw) maybe not so many "great" engineers about, the reality is that the average standard of concert sound these days is significantly better than it was 10-20 years ago and this is all down to the improvement in kit, particularly speakers.
I don't know what you by "specialized design".

All it takes is to aim the center axis of the loudspeaker at the furthest listener and figure out the angle it takes to cover the front row.

No big deal.

As far as the horizontal-what is different about the line array?  At least decent point source speakers have large horns to keep the pattern where it belongs.  Line arrays just "spray" it around.

I would not call a line array  "1 top" unless you like that top to have a different coverage pattern at different freq (Which one do you choose for "coverage"?), and also has all sorts of spurious lobes shooting out the top/bottom and back of the array and within the "coverage area".

The ACTUAL coverage of a line array is quite different than what the marketing departments would like people to believe.

I would not disagree that large scale sound is better than it was years ago-but a lot of this has nothing to do with being a "line array".

About the time line arrays came on the scene-measurement systems became much less expensive-more available-easier to use and so forth.

Also the internet was coming around.  This has allowed the free exchange of ideas-forums such as this-data easier to view/share which I believe has much more impact on the overall knowledge of what is really happening in regards to how loudspeakers behave (not as many believe) and acoustics in rooms.

So as a result there has been a lot more real engineering that has gone into loudspeakers than in years past in which there was a lot of "piling drivers into cabinets" without regard to interactions, cancellations etc.

And the overall quality of quality loudspeaker drivers is another contributing factor-again advanced by measurement and sharing of knowledge.

I believe the line array fad has just been riding the coat tails of these advancements.

I suspect by the end of this decade the industry will see less and less line arrays and more speakers that simply behave better.

These are my opinions and I am sure others will disagree.
Title: Re: How do you calculate PA size?
Post by: Roland Clarke on August 12, 2014, 08:32:56 AM
I don't know what you by "specialized design".

All it takes is to aim the center axis of the loudspeaker at the furthest listener and figure out the angle it takes to cover the front row.

No big deal.

As far as the horizontal-what is different about the line array?  At least decent point source speakers have large horns to keep the pattern where it belongs.  Line arrays just "spray" it around.

I would not call a line array  "1 top" unless you like that top to have a different coverage pattern at different freq (Which one do you choose for "coverage"?), and also has all sorts of spurious lobes shooting out the top/bottom and back of the array and within the "coverage area".

The ACTUAL coverage of a line array is quite different than what the marketing departments would like people to believe.

I would not disagree that large scale sound is better than it was years ago-but a lot of this has nothing to do with being a "line array".

About the time line arrays came on the scene-measurement systems became much less expensive-more available-easier to use and so forth.

Also the internet was coming around.  This has allowed the free exchange of ideas-forums such as this-data easier to view/share which I believe has much more impact on the overall knowledge of what is really happening in regards to how loudspeakers behave (not as many believe) and acoustics in rooms.

So as a result there has been a lot more real engineering that has gone into loudspeakers than in years past in which there was a lot of "piling drivers into cabinets" without regard to interactions, cancellations etc.

And the overall quality of quality loudspeaker drivers is another contributing factor-again advanced by measurement and sharing of knowledge.

I believe the line array fad has just been riding the coat tails of these advancements.

I suspect by the end of this decade the industry will see less and less line arrays and more speakers that simply behave better.

These are my opinions and I am sure others will disagree.

It might well be that you are ahead of the game in terms of large scale point source systems.  In reality I don't know of any other manufacturers that make a box like yours, that in itself means that the tools to achieve what line arrays do are not typically available for the vast majority of suppliers.