For high level soundproofing you need to employ some method of decoupling the framing from the drywall. This can be done by modifying the wall or ceiling framing, but decoupling is often accomplished through the use of Drywall Furring Channel with Soundproofing Clips (IB-1).

Mar 15, 2009 · If you decide to use double sheetrock make sure they are of different thicknesses. You could also use a rubber sound deadener between the sheetrock layers which will provide additional sound deadening, or if you are cheap like me, I used closeout sheet vinyl I bought at a flooring stores. For use as a single-layer application or as a component of multi-layered wall assemblies where sound transmission between rooms or dwelling units is a concern. 5/8"SoundBreak XP panels may be used where Type X gypsum panels are specified in some fire-rated wall and floor-ceiling assemblies (e.g., UL U300, U400, V400 and L500 series). Advantages QuietRock sound reducing drywall by PABCO Gypsum pushes the boundaries of building science to eliminate the need for extra material or complex soundproofing methods. Quiet brand products improve architectural freedom and promote sustainable construction.