Creating a Sound Barrier - Insulation for sound proof walls

Challenge:
One common wall separates two rooms. The sound generated in both rooms carries between them. It is required to have an effective sound insulation barrier between them.
Solution:
Disconnect your common wall structure and apply prior to finishing off your walls for sound insulation. Call a Net Well consultant for techniques for blocking sound and applying an effective barrier to create sound proof walls.
DENSITY -- DISCONNECTION -- SOUND INSULATION
For blocking sound and effective Sound isolation through a common wall, first understand that the noise transmitting through is actually energy. Energy vibrates through any common surface, whether it be brick, concrete, studded walls with drywall, etc. It's like talking into a coffee can that's connected by a string to someone at the other end. The string carries the vibration of your voice, and if you cut the string, you break the communication.
The same holds true for blocking sound transmitting through your common walls. The studs are actually conducting sound, so you need to split the wall apart so the studs inside the wall don't connect both sides together. Once you've done this, simply add our into the wall to create sound proof walls. The density is the easy part here; disconnection requires more effort.

Creating Sound Proof Walls in a New Build Scenario

If you're in the initial building phase, you can choose from two different approaches for blocking sound. 1. You can build a double wall: Two walls standing side by side that do not connect, with applied by staple gun to one or both sides. This creates sound isolation. 2. Build a single wall starting with a 6" wide floor plate. Then stagger 2x4 studs left/right/left/right so that the odd numbered studs support the drywall on Room A's side, and the even numbered studs support the drywall on Room B's side. No stud connects all the way through. Again, add the dB-Bloc to this framing structure and you'll generate a 15-20 dB drop on average. Note that every 3 dB is actually a 50% drop in pressure.

Blocking Sound in Existing Walls

In an existing wall scenario, for maximum sound isolation, you have to be more creative about blocking sound. First, can you frame a new wall as a sound barrier immediately in front of your existing wall? If so, do it, add the barrier, and finish off your new wall for a very simple way to sound proof walls. If not, you're like most of our clients and need a different solution for sound insulation.

The Next Best Technique for Creating Sound Isolation

First, staple right to your existing drywall. Then secure thin firring strips or resilient channels horizontally up the wall. Then apply a second layer of drywall to the firring strips and finish off. This provides the density of the sound material, and the disconnection takes place since the only contact straight through the wall is where the horizontal firring strips overlap the vertical studs in the wall. You'll achieve 95% disconnection, blocking and isolation. You'll achieve 95% disconnection for blocking sound vibration and maximizing your sound isolation!
Other points to consider: First, stuffing the walls with insulation for the purposes of blocking sound actually does little. Why? No density; no disconnection. Second, no matter what blocking, isolation and insulation steps you take, some noise will leak through. Nothing you will do will create total isolation and blocking. Common wall scenarios also share outlet plates, vents, ductwork, pipes, windows and doors where noise escapes the sound block. On average, a standard wall has an STC rating of 38. A staggered wall/double wall with dB-Bloc boosts the STC rating above 60. Again, note that just a 3 dB drop in leakage through the sound block creates a barrier that reduces noise levels by 50%.