L, If you are considering 12 inch center framing, you are on the right track. 2 layers of 5/8 works wonders. Do stagger the joints in both directions. I use 6 inch acoustic insulation in 3 1/2 framing. Also works wonders. You do need both sides of this wall sheetrocked. 1/2 on the other side is fine. Hold the board 1/2 off the floor and 1/2 down from the lid, then fill this void with acousical sealant.
Double width studs for isolation?
Before I drywall my new dedicated room I was wondering if it would be at all beneficial if I added an extra stud to each/some of my 24" on center studs to increase the amount of surface area the drywall was screwing into and thereby conceivably decreasing the "intensity" of energy transfer through them into the outside walls? My goal is to reduce noise transmission through the walls. I will be using 2 layers of 5/8" drywall with Green Glue between. It's not a lot of extra work and I already have some extra studs. Just a thought. Thanks. Grant