Originally Posted by Herman Munster
It would just be nice if there was something that wasn't so darn heavy that would be adequate.....
So far it seems that you will not be able to soundproof adequately. Unless you are commited to spending a lot of time and money to do it "right", you may as well do nothing at all.
As several others have pointed out, an extra layer of sheetrock will not do much if you are not ALSO dealing with the ceiling, floor, door, other walls, etc. And depending on your frame, you very well may NOT want to be hanging a bunch of sheetrock up.
Your best bet is to just make sure to schedule your tracking for when no one else is in the house... and certainly not when people are sleeping.
"Soundproofing" is a lot more difficult than you would think. Even if you built a room within a room with multiple layers of sheetrock all around etc, you still would not be able to track anything semi-loud with someone sleeping only 10 feet away. Sure, a super duper room within room set-up will perform really well in terms of attenuation, but late at night when all else is quiet, a person only 10 feet away is going to hear stuff and they will likely be disturbed by it if they are trying to sleep.
As for hanging extra sheetrock on resiliant channel... in theory, you would not want to do this over your existing layer of sheetrock. Doing so would create a "triple leaf" situation which hurts attenuation performance of the materials. "Triple leaf" means three separate layers... this is a no no... you have one layer of sheetrock on the bedroom side of the wall now, then you have another layer of sheetrock on the recording room side of the same wall now, then you'd be adding a resiliant channel with yet a third separate layer of sheetrock. Theoretically not good.
To do it right, you'd have to remove the existing layer of sheetrock from the recording room side of the wall, hang your resiliant strips directly on the studs, and then place two layers of sheetrock on the resiliant channel. I'm thinking that this may be more work than you want to get involved with. And again, it may be a waste of time anyway if you aren't going to adequately treat the ceiling, floor, door etc too.
However, removing a layer of sheetrock from a small room is really not THAT much work... it's messy, but pretty easy. You could remove it, then stuff between the studs with some good insulation (like R-15 or whatever - or even rockwool or whatever the acoustic people sell) because you most likely have no insulation in there now, then put up the resiliant strips and 2-layers of 5/8 rock. Unless your house is really weak, the two layers of rock on just one wall should be ok.
While beefing up just the one wall against the bedroom will not help too much overall, it might possibly allow you to jerk around with a direct-in electric guitar / keyboard while someone in the bedroom is sleeping, without bothering them. Gee, just the sound of me typing at my computer keyboard in another room over 15 feet away is enough to wake up my wife and annoy her... (I guess I need more sheetrock on my computer room wall!)... so it finally depends on how sensitive the other people in your house are to both loud and soft levels of sound while sleeping... etc.
But... take my earlier advise, skip the soundproofing altogether and just work when no one else is around or sleeping.