Has anyone used "Quiet Rock" sheet rock in room?

An interesting somewhat less expensive idea would be to use the DENSARMOR sheetrock. It is paparless and mold resistant.

The reason I mention this is that we did a re-model for a client and used regular half-inch rock on some walls and the DENSARMOR in the bathroom. He installed wall speakers on both kinds of sheetrock. Just putting my hand on one wall, then the other, it seemed that the DENSARMOR vibrated a whole lot less when playing music from the wall-mounted speakers.

Not scientific, but food for thought. Oh, this stuff is available at Home Depot. You can google DENSARMOR and decide for yourself.

It can replace normal sheetrock or greenboard. My contractors are using is throughout the job. It has a paperless backing so it is not receptive to mold. There is some fiberglass involved, I think.

Again, my own 'test' is one of a field observation, nothing else.