Advice on position of subs for nearly square dance/training room

D

Daniel Postilnik

Junior
Jan 14, 2011
304
1
18
37
San Francisco, CA
I need some advice on how to deploy loudspeakers to cover a nearly square (43' L x 40' W) room that will be used as a dance/fitness group training room. Not a dance club, but similar SPLs for music playback. Will also need to have live vocals go louder than the music. I have requested that some acoustic treatment be installed above the main area in the form of hanging cloud panels.

We currently have existing stock of 4 x Community Veris 1564 speakers that we would like to hang from the concrete slab above (ceiling will be exposed) and positioned in the corners, pointed diagonally down into the room. I need help figuring out what to do about adding subs. While there may be better mid-high speakers for this application, it's a shoestring budget project and I'm being instructed to re-use components we already have.

Keeping the floor clear is definitely a priority for both aesthetic and functional reasons. Without using EASE to analyze, how badly would things go if the subs were hung over the middle of the room, 13' from the walls so they're roughly equidistant from each other and from the walls?

I understand that when flying subs there's a tradeoff of punchiness for even coverage. I am considering JBL VRX915s subs since they fly easily.

Any and all advice appreciated.
 
Cant just slap a Double 18" in the corner and make sure the microphone has a hi pass filter. I guess aesthetically not great but logistically maybe the best option for a shoestring budget. Maybe get a painted white version.
 
Ben Lawrence said:
Cant just slap a Double 18" in the corner and make sure the microphone has a hi pass filter. I guess aesthetically not great but logistically maybe the best option for a shoestring budget. Maybe get a painted white version.
Click to expand...

OK, if we were going this route, I have two channels 1200W continuous @ 4ohms available from an Crown XLS4002 amp. I probably need a sub with a good efficiency rating - any suggestions?
 
Kinda hoping a few other folks were going to chime in. I would go safe with the power though as you can assume they will be cranking it. I would suggest JBL SRX only because I am familiar with them. They can take a lot of power though. Im not sure the 1200w is going to get them jumping. I wonder if there might be a EAW install white version you could get for a steal used on e bay. Something like the SB series. I used to have some of the 150s and they were very nice little subs.
Sometimes the install stuff with binding posts goes for some great prices.
 
To start-I WOULD NOT put the Communities in the 4 corners. If you want the vocals to be clean-this is a bad idea.

I would just go with 2 of them. Do you need to cover the entire room? Probably not. So the pattern would be fine.

Just use 2 of them and do something else with the other 2.

I would fly the subs up with the Communities-in the corner.

That way you will energize all the room modes-so the bass will be more even.

If you put the subs in the middle of the room, you will get all sorts of bad room modes that will mean no bass at certain freq at certain spots.

Your best alignment is to put the subs with the tops-together in the corners-but just TWO corners-NOT all 4.
 
Ivan Beaver said:
To start-I WOULD NOT put the Communities in the 4 corners. If you want the vocals to be clean-this is a bad idea.

I would just go with 2 of them. Do you need to cover the entire room? Probably not. So the pattern would be fine.

Just use 2 of them and do something else with the other 2.

I would fly the subs up with the Communities-in the corner.

That way you will energize all the room modes-so the bass will be more even.

If you put the subs in the middle of the room, you will get all sorts of bad room modes that will mean no bass at certain freq at certain spots.

Your best alignment is to put the subs with the tops-together in the corners-but just TWO corners-NOT all 4.
Click to expand...

Thanks for the input! I get what you're saying about taking advantage of room modes, but can you explain a bit more about what can go wrong with vocals when speakers are in 4 corners? I do need to cover the whole room though, because the usage of the room hasn't been completely determined and may change.

What if I did two pairs of splayed clusters in the corners? Or maybe a center cluster and a delay cluster?
 
Daniel Postilnik said:
Thanks for the input! I get what you're saying about taking advantage of room modes, but can you explain a bit more about what can go wrong with vocals when speakers are in 4 corners? I do need to cover the whole room though, because the usage of the room hasn't been completely determined and may change.

What if I did two pairs of splayed clusters in the corners? Or maybe a center cluster and a delay cluster?
Click to expand...
When you have the same signal arriving at a position at different times (different physical distances) you will have cancellations (based on the difference in arrival times) that are known as combfiltering.

Basically it is a lowering of intelligibility or sound quality.

Also by having the sound "bouncing around" all over the place, you will get even more cancellations.

If you "splay" them, then most likely you will still have cancellations (combfilters) due to the sound from each speaker arriving at a different time at a particular listener position.

 
Daniel Postilnik said:
Also, do you have any experience with the bag end D12E-DA subwoofer?
http://bagend.com/wp-content/uploads/2015/06/D12E-DA.pdf

We have two of these cabinets but we do not have the INFRA sub processor.
Click to expand...

I am not allowed to make comments on other products.

But my experience (yes i had some to play with for awhile in a previous life) says you will better without the processor, in most cases.

This assumes you have a decent DSP and know how to use it.
 
Ivan Beaver said:
When you have the same signal arriving at a position at different times (different physical distances) you will have cancellations (based on the difference in arrival times) that are known as combfiltering.

Basically it is a lowering of intelligibility or sound quality.

Also by having the sound "bouncing around" all over the place, you will get even more cancellations.

If you "splay" them, then most likely you will still have cancellations (combfilters) due to the sound from each speaker arriving at a different time at a particular listener position.
Click to expand...

OK, I suspected you were referring to comb filtering. Is there a way to get a sense of what frequencies will be primarily affected?
 
Daniel Postilnik said:
OK, I suspected you were referring to comb filtering. Is there a way to get a sense of what frequencies will be primarily affected?
Click to expand...

It is pretty simple

You figure out the path length difference.

Let's say it is 1'. That is around 1130Hz.

The first notch will be 1/2 of that freq, or 565Hz.

Then the next and all remaining freq will be spaced at 1130Hz.

So you will have notches @ 565, 1695, 2825, 3955 etc.

If you have any other arrivals, you will ALSO have notches at those freq/path differences etc.

In between the notches there could be a possible addition of a couple of dB.

 
  • Like
Reactions: John Norris
Ivan Beaver said:
It is pretty simple

You figure out the path length difference.

Let's say it is 1'. That is around 1130Hz.

The first notch will be 1/2 of that freq, or 565Hz.

Then the next and all remaining freq will be spaced at 1130Hz.

So you will have notches @ 565, 1695, 2825, 3955 etc.

If you have any other arrivals, you will ALSO have notches at those freq/path differences etc.

In between the notches there could be a possible addition of a couple of dB.
Click to expand...

Thanks Ivan!
 
Top Bottom