Originally Posted by 235
Interesting read Mike. Why did you feel 8' headroom was too low for sound isolation? With clips and 2 layers of 5/8" drywall (GG) wouldn't you only lose a couple of inches?
Ah! Great question -- yes, that's not immediately obvious.
The issue is having the headroom to do the acoustical treatment of the ceiling. If we were going to go with clips and double drywall, we'd have to do that starting from the 8' level and, as you note, we'd lose a couple of inches. But, then we'd have an additional 4" of acoustics over that, then the stretched fabric, and we'd end up with a ceiling that was probably 7'6" or less, which I really felt was going to feel pretty darned low.
What KYDG designed instead was an acoustical treatment plan where all the materials are actually recessed into the joists in the ceiling. The ceiling joists, since they're the floor joists for the level above, are 2x12 (really, about 10.5" deep). With the under-floor radiant and the spray foam insulation in those cavities, we still had about 6" of room available.
So, we covered the foam insulation with a layer of plywood and a layer of drywall affixed to cleats fastened to the sides of the joists. (This was necessary because the foam has to be protected in case of fire, plus it gives us something to fasten the acoustics to.) That left us with about 4.5" of available space in the joist bays -- perfect for the acoustical treatments, the recessed lights, and the 3 ceiling-mounted subwoofers.
Once the stretched fabric goes up, we'll still have an 8' ceiling, but it will be fully acoustically treated.
Since I don't have to worry about anybody walking around upstairs while a movie is on, this was the solution that gave the best acoustical performance in the room and also made it feel the most livable.