How to Soundproof a Wall
A soundproof wall is capable of making your home seem a lot larger just by isolating the sound. Here is a look at how you can soundproof a wall in your home for added noise isolation.
Step 1 - Fill Cavities
The key to creating walls that are soundproof is to fill the cavities between walls as well as you can. You can fill the wall cavities with fiberglass insulation and can add other types of mass to your walls to cut down on the transmitting of airborne sound waves. You can buy a mass-loaded product through acoustical companies that is heavy but not very thick for this purpose.
Step 2 - Caulk
Make sure that gaps are all properly caulked to keep air flow from being allowed to hinder the soundproofing process. The caulk should be an acoustical caulk and it should be used to seal any and all open joints around the entire wall's perimeter.
Step 3 - Add Drywall
When you install the drywall, isolate or float it off of the studs in the wall frames using isolation clips or resilient channel to block some of the structure-borne noise like slamming of doors and footfall noise. When you finish the wall, use a double layer of sheetrock or drywall with a minimum thickness of at least ½ inch.