If you combine QuietRock with Green Glue together, are they more effective? I soundproofed the walls of one room in an old apartment by layering QuietRock and Green Glue together. First, we replaced two of the original 1/2-inch gypsum walls with a single layer of 5/8" QuietRock. There was no decoupling from the wall studs.
The other two remaining walls got doubled up -- I added a second layer of drywall -- QuietRock 510 -- on top of the original drywall and put a layer of Green Glue in between the two. These sound-dampened walls got put to the test when a massive water main project happened outside my apartment building. You can hear the results and compare the decibel readings in this video.
