Acoustic Treatment for a Church

[StevenAndres]

I'm looking to do some sound treatment in my church. I looked at absorption coefficient for Roxul RHT 80. I was thinking I would make panels of 2" along the walls, then a double layer of 2" across the corners for extra bass trapping.

Is that a good idea?

What other information do you need?

[matics]

What size of church are we talking about, here? With high ceilings and carpeted floors you'd be hard pressed to notice anything with further treatment.

[jwl]

Generally a strategy for a large room like a church is a bit different than a small room. Bass trapping is less of a focus, and instead the main goal is to lower the overall reverb time of the room, evenly at all frequencies.

There are several ways to develop this strategy in more detail, but more info is needed.

If it's a typical large church building you will likely need many dozens of 2x4 panels.....

[AV_Dub]

Many dozens is correct!

Just about finished outfitting this Church with Knauf and O.C 703.
120 2X4X2" panels up with 30 to go. They are all spaced about 2" from the walls.

Its worth the expense and effort.. The sound is amazing.










Those panels on the stage wall are 6'X12'X2"

Last thing is some clouds over the stage to address the large flat / sloping areas. They reflect the drums pretty severely.

I'm preparing the Church to be a better live broadcast environment. Gain before feedback is much higher now.

[2manyrocks]

Looks very nice. Did you build the panels?

[AV_Dub]

Thank you! And yes I did build them/mount them.

[AV_Dub]

There are a couple spots (corners in the back downstairs) that are real bass heavy. Actually about 5 feet from the back corners toward the center of the room the bass sounds "Focused" and thick. It's just a 3 foot radius that sounds that way. It's interesting how a room shape effects bass frequencies.

Back to the shop to build bass traps.

[2manyrocks]

120 large panels with 30 to go does sound labor intensive.

Did you use 1x4 wood for all the frames? Some photos look like 1x4's and others --I just can't tell.

What did you use for the large ones? Are they built up of 6x12 material or sub frames joined together to make up the 6 x 12 foot panels?

Also curious how you're going to make the bass traps without eating up a lot of space.

[AV_Dub]

Originally Posted by 2manyrocks

120 large panels with 30 to go does sound labor intensive.

Did you use 1x4 wood for all the frames? Some photos look like 1x4's and others --I just can't tell.

What did you use for the large ones? Are they built up of 6x12 material or sub frames joined together to make up the 6 x 12 foot panels?

Also curious how you're going to make the bass traps without eating up a lot of space.

I bought 1"X12"X12' and ripped them down to 2" strips with a table saw. All the panels are 2"..

The 6ftX12ft stage panels had to be built as 2ftX12ft then assembled together on stage, then stood up and mounted. They were too big to safely transport as 6ftX12ft

It was tough to find so many straight 1"X12". Wiped out 2 Home Depots, and a Lowes. Twice. LOL I think so far about 35 of them. There was no local lumber yard for this one.


Bass traps will need some creativity. The target corners are under a balcony soffit, So i'm going to make 2ftX4ft grills in the ceiling and use 705FRK above the area, and some conservative corner traps maybe 8 inches thick at their thickest. First I'll tack some 705FRK to the soffit ceiling to see if it helps/where it helps the most.

[AV_Dub]

As a disclaimer of sorts, Up to this point in the treatment project I have only addressed the reverb/reflections of the building.

Next will be measurements using REW.

I didn't intend on highjacking this thread. I can start a new one with this project if anyone objects!

[avare]

One note on panel thickness, if you decide to go that way. Build/install them with a minimum of 4" depth to the wall/ceiling.

Andre

[Sebg]

Thank you Andre for your always deep contributions.

(I mean that seriously; I was expecting a profound i.e. deep sign-off).

[avare]

Originally Posted by Sebg

Thank you Andre for your always deep contributions.

(I mean that seriously; I was expecting a profound i.e. deep sign-off).

Thank you.

Returning from invisible closures,
Andre

[AV_Dub]

Originally Posted by avare

One note on panel thickness, if you decide to go that way. Build/install them with a minimum of 4" depth to the wall/ceiling.

Andre

Thank you Andre. Even though the corners are rather shallow angles I can make them in a wedge with 4" sides making the center 8-10" thick. I'll remove the one 703 panel thats in the way and go floor-to-ceiling with the bass traps. they will end up being about 4' wide X 7.5' Tall. If they aren't enough to cure it then I'll try the ceiling treatment too. Thank you again.

Did you mean 4" spacing between the wall and the trap?

[2manyrocks]

Originally Posted by AV_Dub

As a disclaimer of sorts, Up to this point in the treatment project I have only addressed the reverb/reflections of the building. I can say (after being the audio engineer at this Church for 14 years) that the improvements to the acoustics of the room have been nothing short of astonishing.

Addressing every flat surface has eliminated nearly all reflections, by absorption and diffusion. The result is remarkable.

Next will be measurements using REW.

I didn't intend on highjacking this thread. I can start a new one with this project if anyone objects!

Well, the OP didn't say exactly what problem he was trying to solve.

I'm interested in how you solve this corner problem in the space you have. We have a problem to solve with limited corner space, too. If I can tag along and learn something, that would be great.

[AV_Dub]

Originally Posted by 2manyrocks

Well, the OP didn't say exactly what problem he was trying to solve.

I'm interested in how you solve this corner problem in the space you have. We have a problem to solve with limited corner space, too. If I can tag along and learn something, that would be great.

Sure, Maybe we can all learn something from each other.

[AV_Dub]

You know, it seems unusual that all of the excess bass energy is focused to an area of around 5 foot diameter in such a large space. The area is just inside the outer edge of the soffit, about 8 feet in from the corner but still under the soffit. Could the soffit be contributing to this or does it sound like a normal situation?

If there were a way to show it I would say that this picture describes it perfectly, if you see the circle as a 3 dimensional ball. This is about the size of the area. (the same thing is happening on the other side of the room too). The sub is pointed generally in that direction, but a group with their own sound system came in over the weekend and their subs were aimed well away from there, with the same result. So its the room causing it.

One other thing, Sinse The depth of the bass traps will be limited would a very heavy mineral/rockwool be more beneficial than 705?

Thanks

[2manyrocks]

For clarification, is that dark rectangle in the red circle a window or something that can't be covered with a bass trap?

Also curious how much space you have available in this area?

I'm probably totally confused and showing my ignorance , but the superchunk bass corner traps I have read about here seem to span about 3'-4' of the corner and that would mean they are about 1' deep (or more I guess) filled with triangular pieces of fluffy insulation stacked one on top of the other from floor to ceiling?

[AV_Dub]

I did some measurements today and heres what I've got:

Yes those are windows but they are not being used for anything so I can cover them.

That means The face of the traps will be 80" wide X 8' tall, with the backs at 46 inches each to form the triangle (looks like a 60 degree corner or less but I'll take it). Pretty substantial Bass traps!!!

Only thing now is to choose the insulation. LOL, I'm apparently making an extra large recording studio..

[andrebrito]

It is silly to use bass traps in a space like that... that is a large room acoustics matter, not a control room.

[AV_Dub]

Originally Posted by andrebrito

It is silly to use bass traps in a space like that... that is a large room acoustics matter, not a control room.

I tend to agree with you.. but there is a real bass problem in 2 specific places that I need to fix. If not conventional bass traps then what?


I'm open to suggestions

[AV_Dub]

I found this article:
http://www.kongress.no/sitefiles/13/...ski_Wiciak.pdf

The building i'm dealing with has a horseshoe type floor plan, and a balcony. Although not as smooth/round as a horseshoe, It is a half octagon.


It doesn't apply to my bass problem but it's a good read.

[AV_Dub]

Originally Posted by avare

One note on panel thickness, if you decide to go that way. Build/install them with a minimum of 4" depth to the wall/ceiling.

Andre

Andre, Did you mean install them with a 4" gap between the wall and bass trap material?
I don't want to assume.

[Glassindo]

Originally Posted by AV_Dub

There are a couple spots (corners in the back downstairs) that are real bass heavy. Actually about 5 feet from the back corners toward the center of the room the bass sounds "Focused" and thick. It's just a 3 foot radius that sounds that way. It's interesting how a room shape effects bass frequencies.

Back to the shop to build bass traps.

IMO it's not a corner problem...it's a balcony problem...I have mixed many shows from under a balcony and every single one is a crazy low end nightmare...I donut think you can do much there as I'm thinking that under the balcony is just where low in a room like that just ends up having tremendous amounts of energy.

Very cool that those panels are taking out the crazy reverb of the room...churches are the worst..nice job man!

[Glassindo]

I believe that 4 inches of 703 is much better at absorbing across the board...there is a chart in Rod Gervais book...I circled a couple and I believe that 4 inches seemed to be the one that covered the most ground


PS. That book is a MUST HAVE...it's not a beginner book by any stretch...even though it's helpful to beginner acoustic guys like me.

[AV_Dub]

Originally Posted by Glassindo

IMO it's not a corner problem...it's a balcony problem...I have mixed many shows from under a balcony and every single one is a crazy low end nightmare...I donut think you can do much there as I'm thinking that under the balcony is just where low in a room like that just ends up having tremendous amounts of energy.

Very cool that those panels are taking out the crazy reverb of the room...churches are the worst..nice job man!

Hey thanks for the response. I'm going to make some rather epic bass traps to try and cure it anyway. If it doesn't, My home surround studio will have the coolest bass traps on the block.

Yep the reverb is pretty much completely gone from this Church. That might be a bad thing for most live venues but this one is being prepared for live dialog broadcasting, and drama productions with choir and loud worship team video taping. I wanted the room to be more under control if that makes any sense.

[AV_Dub]

Originally Posted by Glassindo

I believe that 4 inches of 703 is much better at absorbing across the board...there is a chart in Rod Gervais book...I circled a couple and I believe that 4 inches seemed to be the one that covered the most ground


PS. That book is a MUST HAVE...it's not a beginner book by any stretch...even though it's helpful to beginner acoustic guys like me.

I'm planning on some triangular wedge type traps. Looks like the best I can do is 80" wide X 8 feet tall with 46" short sides. I have installed all the broadband absorption (703) the room can handle! These will be strictly Bass frequency traps.

I'll look into the book.

Thank you,

[Glassindo]

Originally Posted by AV_Dub

Hey thanks for the response. I'm going to make some rather epic bass traps to try and cure it anyway. If it doesn't, My home surround studio will have the coolest bass traps on the block.

Yep the reverb is pretty much completely gone from this Church. That might be a bad thing for most live venues but this one is being prepared for live dialog broadcasting, and drama productions with choir and loud worship team video taping. I wanted the room to be more under control if that makes any sense.

Of course that makes sense...really good sense actually.

Good luck with the bass traps. If it works it would be pretty cool.

[2manyrocks]

Originally Posted by AV_Dub

You know, it seems unusual that all of the excess bass energy is focused to an area of around 5 foot diameter in such a large space. The area is just inside the outer edge of the soffit, about 8 feet in from the corner but still under the soffit. Could the soffit be contributing to this or does it sound like a normal situation?

Keeping in mind that I'm not so knowledgable about this, but my thought is what is happening is like when water crashes into the land at the beach. Once the energy gets dissipated, it's calm at the edge, but turbulent where incoming waves meet the water running back to the sea.

So my uneducated guess is it seems calm in the corner, but there's a mess in the area where incoming sound energy meets the reflected sound energy and it's focused under the balcony because there's not much else place for it to go.

I think you're on the right track to absorb the bass in the corner and under the balcony ceiling.

[AV_Dub]

Originally Posted by 2manyrocks

Keeping in mind that I'm not so knowledgable about this, but my thought is what is happening is like when water crashes into the land at the beach. Once the energy gets dissipated, it's calm at the edge, but turbulent where incoming waves meet the water running back to the sea.

So my uneducated guess is it seems calm in the corner, but there's a mess in the area where incoming sound energy meets the reflected sound energy and it's focused under the balcony because there's not much else place for it to go.

I think you're on the right track to absorb the bass in the corner and under the balcony ceiling.

The proof will be in the testing! I know I'll be endlessly thinking "there must be something more I can do" but thats just the way I am with everything.. Testing will at least help me decide when enough is enough. (I hope lol)