 Your goal for a successful treatment for combatting the bleed of noise through a wall is to line the wall with additional density and break the connection points inside the wall. This will impair the wall's ability to conduct vibrations, and force the collapse of the transmitting soundwave inside the wall. Your actual treatment will depend on your starting point: Is your wall finished, not yet built, or exposed frame?
Before we explore your treatment options, let's review the behavior of a sound wave. When sound bleedds through a common wall, it is actually transmitting structurally through your common contact points. In most cases, this will be a common set of wall studs supporting drywall on both sides. In other cases, the common wall could be cinderblock or poured concrete. With any of these structural assembly's, when a sound wave strikes against the common wall, the wall will begin to ebb and flow like an ear drum. Although this process is naked to the eye, the surface is actually accepting the resonancy of the sound wave. The wave itself is traveling from molecule to molecule, passing along the energy by expanding and contracting. The molecules themselves do not move, they remain stationary, and simply expand and contract.
When the airborne molecules pass the sound wave energy on to the structure borne molecules, the sound wave will pick up speed. Remember the your wall has a tighter molecular structure than the air, and will pass energy along more quickly. If your common wall has a connection point straight through, this becomes your path for noise. |