We are getting ready to begin a multi-room renovation project and are thinking about sound deadening. We want to either add sound deadening insulation or acoustical drywall to the interior walls but are not clear as to the advantages/disadvantages to each. This would only be for the interior walls. We are not concerned with thermal properties, only acoustical.
Can you provide some tips on which is better?
If you're only going with one or the other, my personal opinion would be to go with accoustical drywall and seal the perimiter with accoustical caulk. Insulation goes between the studs, so you could still have vibrations traveling through the studs themselves and the top and bottom of the wall's frame. If you use sound-deadening drywall like QuietRock or use a double layer of regular drywall with Green Glue in the middle, you can avoid that flanking much easier since you're covering the entire area of the wall's frame. Of course, worst-case sound situations could still allow sound to flank through the floor or ceiling, under or over the frame, and through the floor or ceiling of the neighboring room, but I'd think that would be an extreme case.
