Three of the four walls in the theater room I am getting ready to begin construction on are concrete foundation walls. My plan for the fourth wall is a double-studded wall (not offset--actually 2 separate 2x4 frames). This wall will use resilient channel with a sheet of 5/8" drywall, then green glue, then a sheet of 1/2". The wall will be insulated with R-13 with a sheet of 5/8" on the back side. There will be about a 1" gap, and then the 2nd studded wall will have R13 and 5/8" drywall on the back side. Your thoughts on this? My big question is what I need to do with the other 3 walls (against the concrete). For budget reasons, I was thinking about only doing a 2x4 wall with R-13, resilient channel, and one sheet of 5/8" drywall? What do the soundproofing and acoustic gods have to say about this? One more thing, what can I use to sandwich between the studded walls and the floor joists above? Some sort of foam? Again, budget is going to limit me to a certain extent (room within a room was dropped a while back). Thanks for your thoughts!