Common walls bleed noise because they are not build properly. Vibrations structurally pass through common contact points inside the wall, namely, the framing. To properly insulate a wall against noise bleed, there’s a simple 3 step approach to force the collapse of this vibration. The treatment can collapse up to 90% of the noise bleed through the wall.
Step 1 is density. Think of a tuning fork. If it’s free to vibrate, it will produce sound. Think of a wine glass. If you rub your moist finger around the top, it will vibrate and produce sound. Sound is vibration. But take the flat of your hand and touch the vibrating surface, the sound dies. The same approach should be applied to a common wall. Add density. It comes in the form of a mass loaded vinyl called dB-Bloc. Staple it up to your existing finished wall, or your exposed frame and you kill the vibrations.
Step 2 is disconnection. Think of a string pulled tight between 2 coffee cans. Then snip the string. By breaking the contact point, you force the collapse of the transmitting sound. The frame inside a common wall serves the same function as the string. The goal is to disconnect the framing. This can be done by adding a simple set of furring strips to the wall to create a new air gap, separation, between the new and final layer of drywall and the existing frame. This will force the collapse of the transmitting vibration.
Step 3 is to seal up the joints in the drywall and minimize air gaps. Sealant’s are available at your local home building center. This 3 step layering technique is featured online at NetWell Noise Control. For help, call to their desk at 1-800-638-9355.