new room within room design - advise please

egcc · Post by **egcc** » Wed Jun 25, 2003 9:09 am

The new room is about 18'6" x 22'. Ceiling will be about 8' on each side climbing to 11' in the middle. It's an external roof. Question is - is it worth doing two separate ceiling frames for isolation or not? Either way the drywall will be hung on resilient channel. The other question is how to secure the top of the inner wall - how should it attach to the rafters ?

attached file shows one ceiling frame

egcc · Post by **egcc** » Wed Jun 25, 2003 9:11 am

attached file shows two separate ceiling frames

Post by **John Sayers** » Wed Jun 25, 2003 10:26 am

So how heavy is your rain?? I would have though that a double layer of drywll on RC would be sufficient to cut out that rain noise. An extra ceiling frame is a lot more expense and probably not worth it.

cheers
john

knightfly · Post by **knightfly** » Wed Jun 25, 2003 6:46 pm

Can you post a drawing of your proposed wall construction, showing each layer, frame, etc, from either the top or side, with labels so we can get a better idea of what's involved?

egcc · Post by **egcc** » Thu Jun 26, 2003 3:33 am

Here's a file with the basic details. My goal is sound isolation and insulation. Location is a residential neighborhood which is fairly quiet. I'm sure the basic shell with resilient channel/multiple drywall layers/rockwool will take care of road traffic noise and rain noise. However, the room will be recording space and/or home theater...I'm a little more concerned about leaking too much sound out. I appreciate your help and advise.

knightfly · Post by **knightfly** » Thu Jun 26, 2003 6:56 am

Looks like you've covered all the basics already. You'll need to find a source of acoustic rated caulk and seal EVERYTHING, and pay particular attention to doors and windows.

Since you're using RC on all the walls and ceiling, you won't need to isolate the inner stud frames from the rafters. You'll have as good isolation there as with the ceiling - weakest link theory...

You will get some degree of structure-borne sound through the 2x12 joists without a floated floor involved, but I doubt it will amount to much. If you're intending to record Death Thrash Rollerskate Punk Earthquake music in the space, I'd think about a floating concrete floor... Steve

egcc · Post by **egcc** » Thu Jun 26, 2003 8:10 am

Steve,

Death Thrash Rollerskate Punk Earthquake music ?????? lol ... Most likely not, although I am a guitar player, so there may be some fairly loud guitar involved now and then. I will pay attention to sealing everything with acoustic caulking.

You might have a comment on this - the garage space under the new room is just regular garage space. The reason I had RC on the ceiling of the garage, and insulation in the ceiling joists between the garage and the new room was to try to help control some of that sound being transmitted through the floor structure.

I guess the walls absorb the highs/mids, the ceiling absorbs lower mids, and the floor and garage space absorbs the low mids and lows. Hopefully it will sound fairly even and not require a lot of treatment.

Thanks for your help!

knightfly · Post by **knightfly** » Thu Jun 26, 2003 8:55 am

Yeah, I caught the RC and multi-layer under the joists, good move - just be sure to seal around that ceiling (downstairs) all around as well, and don't let the RC go clear to the walls, it should stop about 1/2" short. You should then caulk each layer as you put it up on the RC, so that the only thing touching the downstairs wall is CAULK. Otherwise, anything that excites the ceiling will transfer to the walls and outside easier. Also be sure to mark (masking tape) where the joists are so you DON'T put a screw thru the panels at those points - no need to waste the RC by "shorting" it...

With your multi-layer wall covering, you may find a need for a bit more bass trapping due to increased stiffness in the wall leaf, not sure about that though. Generally, I tend to first build the room with what I KNOW it needs (sound proofing) then worry about what it sounds like inside AFTER. For one thing, construction techniques can vary the end result from what we predict, and I hate to do un-necessary things (unless they're FUN)

I can't believe you never heard of DTRPE music; man, I thought I was the one that's out of the loop. The stuff take special speaker arrays, consisting only of 100 18", 2000 watt subs and banks of 400 1" titanium tweeters, powered by a microwave oven pumped through 100 2 kilowatt Linear CB amps - you could do without the tweets, but then the bearing noise of the rollerskates would get buried by the Earthquake track, and it just wouldn't sound authentic...:=)

egcc · Post by **egcc** » Sat Jun 28, 2003 2:53 am

Thanks for the help. I'll post more about the project as construction begins late August. I'll be doing a lot of the work myself, except for the framing of the outer walls and roof of the new room.

Oh - and I'll be keeping my ears protected against any DTRPEM!

Eric