James
Lord of the Erg\o/s
When I "designed" the layout of our house, one of the gambles we took was locating my music room next to our bedroom. I figured that we won't be listening to music and trying to sleep at the same time. Nonetheless, I wanted to sound-proof the drywall-lined partition as much as possible.To get really good isolation from the bedrooms next door will take a bit of thought within the design of the project. The main issue is that it's difficult to get enough mass in place to easily provide a lot of isolation at LF; you find that the isolation of drywall drops off a lot at LF; and most especially because good acoustic isolation is straightforward to design but naturally remains very sensisitive to detailing and workmanship on installation.
For example, addressing one point aleready raised in thread: one simple trick to help before over-lining lining walls (with independant linings) is to use a parge coat - a base coat of gypsum plaster 6-8mm thick simply to seal the base masonry on party walls (esp the joints where mortar is often missing/poorly placed). When you are looking for 50dB+ of separation a hole the diameter of a pencil can measurably spoil the results...
The wall is standard 4x2" timber framed. The main difference was acoustic insulation (Pink Batts Silencer) within and a double layer of plasterboard on each side. Nothing special was done to the ceiling (which has standard thermal insulation) or floor, which is carpet over concrete. The result surprised me. When listening at a civil level in the music room, you'd be hard pressed to tell from the bedroom. But when cranked up to as loud as I'd ever listen, there is a tiny bit of bass leakage.
For our purposes, it was more than adequate. If I had neighbours demanding absolute silence, then I suspect a double, decoupled wall might do a much better job.