Related to my most recent post regarding optimum sizing for in-wall backboxes, I have now turned my attention to another issue that we must resolve. I am putting an addition on my house. I would like to minimize the sound transmission through the common wall (formerly an exterior wall--now interior)between the addition and existing house. I have the luxury/flexibility, now, to insulate and/or apply different products to the wall framing to accomplish my objective. The room in the existing house is a "family room" that will be used for home theater/tv/... for all of us, though primarily my 4 young kids. The addition will be a room in which I'll hope (fingers crossed!) to be able to sit quietly and listen to music from time to time. In any event, I hope to be able to carry on a conversation without having to talk above the roar of noise which will undoubtedly eminate from the family room when kids are watching anything.
I am not trying to go too crazy here (as in recording studio dead quiet), with multiple layers of sheetrock built out from the studs, which I've seen done. I would just like to simply, and relatively easily, do the best I can to stop sound from being easily transmitted through my common interior wall. The builder has recommended the use of a 1/2" "soundboard" (described as being similar to a backerboard used for tiling floors)behind the 1/2" blueboard we'll be using prior to plastering the walls. We also discussed the use of a high density fiberglass insulation, though, based on some posts in the other thread, I don't know if fiberglass would be the best choice. I don't need any true "insulation," since this is now an interior wall. We can simply leave the existing insulation in place too, since it is in quite good shape.
Many thanks in advance for any and all suggestions.