Soundproofing a narrow room

[ebop]

Hi everyone. Even though this is my first post, I have been reading through the forum for quite some time now and have learned a lot from everyone... thanks!

I am finally in the process of building a dedicated HT in an extra room in the house. I have the problem that the room is very narrow (only 11'8" wide). After seating is in place (3 seats in each row) I am left with only 22" of walking space in each side!!!

All walls are concrete and I want to soundproof them them, not because of neighbors (don't have any) but because of acoustics. However, I don't want to unnecessarily lose any more width in the room! Here are my options:

1. Place a panel of drywall directly on the plastered concrete wall, with green glue in between. With this solution I would lose very little space. Will GG work well if it is sandwiched between drywall-wall instead of drywall-drywall?

2. Decouple the drywall from the wall 1", using fiberglass in between. With this solution I would lose a bit more space than #1, but I'm willing to go for it if it is significantly better.

3. Decouple the walls 1" AND use GG between 2 drywalls. This would obviously be the best way to go, but it would take the most amount of space. (leaving 19-20" of walking space)! Do you think it is significantly better than #1 and #2?

What would you guys do for this room? Any help is appreciated!

Thanks!

 

[jostenmeat]

Hm. I shouldn't even be posting here due to my severe lack of qualification.

But isn't concrete soundproofed anyways?? If you are looking to "acoustically treat" then you can use panels and traps.

For helping to both soundproof and treat, I know some will use more thickness than 1", and use staggered studs, filled with fiberglass. But you lose considerable room volume.

Dunno man!

You can probably glean a ton of ideas from this forum

 

[TLS Guy]

Hi everyone. Even though this is my first post, I have been reading through the forum for quite some time now and have learned a lot from everyone... thanks!

I am finally in the process of building a dedicated HT in an extra room in the house. I have the problem that the room is very narrow (only 11'8" wide). After seating is in place (3 seats in each row) I am left with only 22" of walking space in each side!!!

All walls are concrete and I want to soundproof them them, not because of neighbors (don't have any) but because of acoustics. However, I don't want to unnecessarily lose any more width in the room! Here are my options:

1. Place a panel of drywall directly on the plastered concrete wall, with green glue in between. With this solution I would lose very little space. Will GG work well if it is sandwiched between drywall-wall instead of drywall-drywall?

2. Decouple the drywall from the wall 1", using fiberglass in between. With this solution I would lose a bit more space than #1, but I'm willing to go for it if it is significantly better.

3. Decouple the walls 1" AND use GG between 2 drywalls. This would obviously be the best way to go, but it would take the most amount of space. (leaving 19-20" of walking space)! Do you think it is significantly better than #1 and #2?

What would you guys do for this room? Any help is appreciated!

Thanks!

That's a tough one. I assume this is a basement. That being so, and having owned three houses with basements over 38 years, I can tell you that they are prone to unexpected water problems. Also the room really needs isolating from the damp concrete attracts.

Really it needs studs to the concrete, insulation between the studs, and then sheet rock. I would not glue anything directly to concrete. That will set you up for trouble, as you won't get it off easily if you have to.

 

[bpape]

The 3rd option is the best. #1 will work but it's not going to give you a ton.

Also, consider that the reason drywall walls work a little better is because of the insulated framing behind them acting as a type of panel absorber.

Bryan

 

[Ted White]

I hate to say this, but none of those will work particularly well. First of all concrete is commonly thought of as the ultimate isolator of sound but lab tests show this is far from true, especially with block walls.

#1 Any constrained layer damping material needs to be placed between two layers of mass with similar flexibility. Concrete and drywall are not similar, obviously.

#2 adding 1" of airspace might be better, but a small air cavity will cause problems. The system is still rigid and coupled, and will definately makes things worse at some frequencies. That new drywall layer + airspace will create an amplifier for certain frequencies, typically higher freqs.

#3 Adding GG will help, but only a small amount. Still have the small air cavity, and rigid, coupled framing.

This has been tested and documented by the National Research Council of Canada. Really the only thing you can do that is effective would be to install a new framed wall that does not contact the concrete wall. Minimum 2x3 steel stud, at least 1/2" away from concrete. Now you have introduced decoupling.

Add R11 or R13 fiberglass. Now you have introduced absorption.

Add double 5/8" drywall. Standard stuff, nothing exotic. Now you have introduced (more) mass.

Add the GG at this point. Now you have introduced damping.

That's not the answer you wanted, but that's why many people choose to do nothing.

 

[Ted White]

Bryan, I tried to PM you but I have insufficient posts to be able to do this. Maybe you could PM me so I could reply to you?

 

[Ted White]

Sorry,

I re-read the OP and see that you planned to decouple in options #2 and #3. Somehow I had it in my mind that you were simply introducing an air cavity, but still coupled.

So your option #3 is what I have suggested, assuming you mean true decoupling (separate stud wall)