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[Justin Philip]

There is no way on earth the ACTUAL response can look this smooth at 2k with two sets of speakers running. You are being misled, through manipulation of the data/smoothing/etc. There will be comb filtering EVERYWHERE at 2k with two widely separated sources. That is simply the physics of sound, and cannot be overcome.  I've been watching this thread, and you've heard some good advice. It is time to ask for a demo.....walk the room with two line arrays pushing mono pink noise, and it will all become clear.....

Ed Walters

Ok.

I mean I know I am on a prosound forum..but I am not an expert at any of this. So what can I ask the designer to further investigate what's going on?

[g'bye, Dick Rees]

Ok.

I mean I know I am on a prosound forum..but I am not an expert at any of this. So what can I ask the designer to further investigate what's going on?

As he said:

Ask for a demo.  Demand sonic proof.

[Ivan Beaver]

As he said:

Ask for a demo.  Demand sonic proof.

And during the demo-be sure to WALK the room and LISTEN.  Be sure to go to the extremes-sides-front-back etc.

Remember that a lot of people sit in those spots as well.

While in the middle of the room-listen to just ONE of the arrays-and then have the other one turned on. and hear the difference.

If the demo is only with a single array-then that is NOT representative of what the actual install will be.  That is part of the problem with two loudspeakers covering the same area.

You should be listening to as few loudspeakers as possible.  More IS NOT better in the loudspeaker world.

When I design-I try to start with a  single loudspeaker (if possible) to try to cover the room.  And try not have as little overlap as possible.

Something else you might as the "designer".  Are they willing to guarantee the coverage?  Will they guarantee any "performance" scores-Alcons-STIPA-coverage etc?

[Ivan Beaver]

Ok.

I mean I know I am on a prosound forum..but I am not an expert at any of this. So what can I ask the designer to further investigate what's going on?

You could print out some of the concerns that have been expressed in this thread-and show them to the designer and see what response they have.

While this can be an awkard approach-it might give some insight-one way or the other.

But the bottom line is-If the designer is willing to stand behind the design and "make it right" if it doesn't work-then you have nothing to lose.  Of course actually "making that happen" is not always easy.

[Doug Fowler]

There is no way on earth the ACTUAL response can look this smooth at 2k with two sets of speakers running. You are being misled, through manipulation of the data/smoothing/etc. There will be comb filtering EVERYWHERE at 2k with two widely separated sources. That is simply the physics of sound, and cannot be overcome.  I've been watching this thread, and you've heard some good advice. It is time to ask for a demo.....walk the room with two line arrays pushing mono pink noise, and it will all become clear.....

Ed Walters

+1

Be SURE to listen using pink noise.  It reveals things you may miss using music.

[Ivan Beaver]

Ok.

I mean I know I am on a prosound forum..but I am not an expert at any of this. So what can I ask the designer to further investigate what's going on?

Just one more thought-if the "idea" of the system is "stereo", then each side of the PA HAS to cover the entire room-BY ITSELF or people will not hear information that is panned to the side.

So ask to see a model with just ONE cluster on (as if the signal is panned to the left or right).

If you get a demo-listen to just ONE side and see if it covers the room.

Just because you see a particular setup all the time does NOT mean that it is correct or will do a good job.

This is not a "particular loudspeaker model" type of thing-but rather a basic design issue.

[Mark McFarlane]

As he said:

Ask for a demo.  Demand sonic proof.

Curiously, is it reasonable/customary to ask a vendor to provide a demo in your space of a 9 box hang per side? It seems like a lot to ask for.  How frequent is this type of request made?  Brad? Ivan?

[Ivan Beaver]

Curiously, is it reasonable/customary to ask a vendor to provide a demo in your space of a 9 box hang per side? It seems like a lot to ask for.  How frequent is this type of request made?  Brad? Ivan?

Typically a "demo" is just the major part of a system-not an entire system.  Because that is practically an install.

HOWEVER-if there are some "questionable" aspects-then those need to be addressed.  Such as having 2 sources covering the same area.

And it doesn't do any good to bring in 2 line array elements-what does that prove?  But if a a point source design was used and that single point (or combination of boxes) would cover most of the room (as it should), then the little fill areas are not worried about.

That is where good modeling comes in (and not models that have been turned into something "pretty") but rather models that show more of what is really going on.

When I do models-I look at a wide range of freq-different amounts of smoothing and so forth-to come up with what I feel is a reasonable expectation in the room.

This is a combination of experience-the model and "intuition". 

Here is a story that was a "lesson learned".  We were contracted to do a consultant designed job-and I wanted to substitute a different system that I felt would do the customer a better job.  So I brought in a system that would fill about 80% of the room.  The room was pretty live.  So we did a side by side with just ONE of the cabinets in the original design ( a 30x30 cabinet). 

The customer listened to both system and walked around the room.

When they started talking I realized where I had screwed up.  They said "Your system sound a lot better and covers a lot more of the seats-but we feel the original system offer a little bit better clarity when you are in front of it."

WELL DUH!!!!!!!!!!!!  A large narrow horn simply wasn't energizing as much of the room as I was-yet it would a goo d number of those cabinets to actually do the job.

We were not comparing apples to apples.  If I had only turned on one of the cabinets in my cluster, I think the job would have gone the other way-but I was trying to prove something, while they were listening to something different.

And that was not the only time I "lost" a demo because the customer was looking for a "particular" thing out fo the system-no matter how impractical or unrealistic it may be in the "grand scope of things".

So as usual-it depends-------------------

[Brad Weber]

Curiously, is it reasonable/customary to ask a vendor to provide a demo in your space of a 9 box hang per side? It seems like a lot to ask for.  How frequent is this type of request made?  Brad? Ivan?

This is where line arrays pose a bit more of a challenge as any differences in the configuration can affect the results, thus to hear how what is proposed might work in your or a similar space you almost have to mock up what is actually being proposed in terms of not just the product models but also the hang points, the number of boxes and the angles between them, the array processing, etc.

For a big project this might not be an excessive request at all, although if the space does not exist then you may have to find some other similar space to use for the demos.  It may also depend on the situation.  If the vendor knows they have the project as long as the demo is successful or if it is a vendor that has the project demoing multiple options then they may be better able to justify or recover the associated costs.  If it is three or four vendors with competing products and one will be selected then they may each have to assess the potential cost/benefit and decide, especially if there is any known bias to one product or if the decision will also be greatly bid cost influenced.  If it is simply "Hey, come show us this system" then I would not expect that much effort to be invested.

Another option is that they may suggest a similar system already installed in the area.  How well you can relate what that situation and what you hear to your application depends on your experience but it can often be very useful for getting a better fell for many aspects of the proposed system.

[Justin Philip]

UPDATE:
Hi everyone. Just wanted to give an update on this project. We are officially a month into having services at the new facility. We are still working through some challenges. The main thing is we need to do some acoustical treatment. There's a 4-5 sec flutter/slap back echo in the back. So the mix sounds a little muddy..vocals are not intelligible during louder songs. I know we should have done this earlier in the project but some unfortunate things happened like our main designer having to leave the project due to illness with his wife etc.

I contact some companies in the Houston area. HPF acoustical, CTSI, Russ Berger, and Bai from Austin. Does anyone have any other recommendations?

I will post pictures of the install later today after I swing by the church.

[ProSoundWeb Community]