Sound Proof Walls and Firewalls

If you want to limit the amount of sound that escapes from a room, incorporate one or all of these five strategies into wall and ceiling construction.

-- Add sound-absorbing material into the stud or joist bays (Step 1).
-- Separate the two sides of the wall from each other. One way to do this is by screwing resilient steel channel to the wall or ceiling, then screwing the drywall to the channel. Other methods include staggering 2x4 studs on a 2x6 soleplate, or even framing two walls, then separating them with a 1-inch dead-air space. You'll gain additional isolation by gluing and screwing the second layer of drywall to the first, not to the framing (Step 2).
-- Increase the mass of the wall or ceiling by using thicker panels and/or installing multiple layers (Steps 3 and 4). Install a sound-reduction board as the first layer and top it with drywall.
-- Seal sound pathways by caulking, gasketing electrical outlets, and weather-stripping doors (Step 5).

Successfully decreasing sound transmission makes a room more acoustically reflective. You'll probably need to consider adding sound-absorbing materials such as carpeting and drapes.