I am planning a home theater build in my basement. I was only planning on inslulating the walls and ceiling with fiberglass prior to 5/8 drywall, with DD ceiling, taking no other measures to soundproof the room. I wanted to reconsider before its too late. The wall top plates are screwed into the joists(actually 3/4 osb fireblock). So the walls are not decoupled, in fact the front half of the left wall was already existing as part of the staircase, this is load bearing and could never be decoupled.
A few facts
The room is narrow at 10.8 ft x 21.2, located in the basement, two walls border the foundation,
1 wall borders a unfinished storage room, and the remaining wall borders a game room and the staircase to upstairs.
Above the theater is the never used formal living room, no bedrooms are located on first floor.
Room inside a room, stagard stud, clips and channel on walls with DD/GG, is out due to narrow room.
Main goal would be to decrease sound to upstairs.
Is there any chance I could be happy using only massive amounts of insulation in the rafters and walls with DD ceiling?
Would adding GG between DD be of benefit if it is only done for the ceiling, mounted directly to joists?
Dont really want to go here but, Would whisper clips and hat channel with DD/GG on ceiling only, be of any benefit since the rest of the room is not decoupled?
I would appreciate any input to help me finalize my soundproofing plan.
I can't give you definitive answers but here are a few half way (less than half way) educated pointers.
Start with doing research on thesoundproofingcompany.com.
In my opinion it is true that if you do not decouple the ceiling it is probably not worth doing too much. The double drywall and gg on a non decoupled ceiling will not be worth your time and money.
It is a good idea to put insulation in the walls to prevent the cavities from resonating. But, the sound proofing benefits are minimal. I am not saying it won't help at all but it will not provide the results you are looking for.
The ceiling is the most important surface to decouple. You could opt to decouple the ceiling with clips/channel and do double drywall with gg. Then, if you do not have the budget to clip/channel the rest of the room you could move the walls away from the foundation walls thereby naturally decoupling them and using double drywall with gg. You would need to clip/channel the stairwell wall but buying the stuff for that wall will not be too expensive. Or you could build a staggered stud or second wall in that location even though you would lose a few inches.
Of course if you do these things you will also want to address the doors and hvac to name a few other areas.