Could this work? Wall construction

[RichHead]

Ok, been around the world and back again. Reading, reading, and more reading. I have a question about wall construction...and whether this might work (assuming I could seal my exterior wall as well).

http://www.westernairsystems.com/walls.gif

It seems the double wall is primarily used as an interior wall seperating rooms, but I'm trying to maximize my space (I will have only one room). My main concern is "soundproofing", but I really haven't found alot of information pertaining to exterior walls. Anybody have some thoughts on this? Or should I just go to bed now?

.....Thanks in advance

[RichHead]

I guess I should ask...would that give me any kind of decent STC rating?

[knightfly]

Rich, you won't get any better advice than the comments you got from Wes over at RO - (yeah, I'm one of the moderators there, as well as at the Construction forum on John's site)

Two basic rules of soundproofing - 1 - Mass Kicks Ass and 2 - If it won't float, it ain't soundproof (this second one isn't completely true, sometimes (HVAC, for example) we have to use other means - but generally, everything you do needs to be built with cabinet-maker tolerances and caulked with non-hardening, high quality caulk, or the design isn't going to work. By NOT following that advice, you can lose 20 dB of performance or more.

Wes and others correctly pointed out that TWO masses and only ONE air space is the way to go - since you've not started, his suggestion of adding the cement board for additional mass is a good one. Also, since you're starting from scratch, if you need more usable space you have the option of making the footprint larger to allow for the extra air space, which Wes is also correct in stating will be better. (The wider the air gap, the softer the "spring" between the two leaves of the wall - plus, sound attenuation follows the "inverse square law")

About the only thing missing from your #3 drawing (at RO) is mention of Resilient Channel - I would mount your inner layers on RC placed directly on the studs at 12" centers (3 layers is heavy) - here is a link to more info on that process, if you need it -

http://www.homerecording.com/bbs/sho...threadid=76374

Hope that was helpful... Steve