Soundproofing 101

5 Elements of Soundproofing

There are 5 elements in sound reduction (Absorption, Damping, Decoupling, Distance and Mass) The “Absorption” aspect in soundproofing should not be confused with Sound Absorbing Panels used in acoustic treatments. “Absorption” in this sense only refers to reducing a resonating frequency in a cavity by installing insulation between walls, ceilings or floors. Acoustic Panels can play a role in a treatment only after walls or ceilings have been soundproofed, reducing the amplified reflection in the source room.

1. DECOUPLING

Decouple your walls ceilings and floor for increased performance.

The first element is decoupling. Keep in mind that sound is nothing more than a vibration. The vibration will travel (conduct) easily if there is a nice solid direct pathway to follow, like a string between two cans. If we cut the string, however, we “decouple” the pathway, and the sound vibration stops (no conduction).

Obviously for soundproofing, we want less sound vibration to travel from one side of the wall to the other. It is therefore enormously beneficial if we decouple the framing in our walls and ceilings. It’s simple, inexpensive and highly effective.

 

 

2. ABSORPTION

Adding insulation reduces sound a little, but not enough to consider a soundproofing solution

 

Air cavities will resonate. Ever “heard the ocean” in a seashell? Ever blow across the top of a bottle and heard the sound? Both sounds are actually the trapped air resonating. A hollow wall will also trap air that will resonate. When the wall is vibrated by sound (from your neighbor), the air in the wall cavity is also vibrated, just like a drum. This air cavity is another means for sound vibration to travel from one side of the wall to the other.

 


Absorption Wall Construction Diagram

Even though the wall framing is decoupled, the vibrating air cavity will still transmit some sound through the wall between the wall studs. Simple Sound Attenuation Batts (SABs) will absorb some of this (absorption).

Insulation helps and should be done if possible, but the vibration reduction is smaller than the other 3 Elements. You can use other insulation materials as well like mineral wool. The key is to keep the density low. Don’t compress or pack the insulation.

3. MASS

mass-element

 

A very important element. For sound to conduct through a wall, it has to actually move the wall ever so slightly. Enter: MASS.   In this case, we simply mean to make the walls as dense or heavy as you can. Materials like QuietRock (equivalent to 8 sheets of sheetrock) and Mass Loaded Vinyl are very effective.

Decoupled wall with Mass Add

Note that adding mass improved things. It’s harder for sound to move this heavier wall. You will still hear low frequencies (bass) quite easily.

4. DAMPING

Apply Green Glue Damping Compound to you assemblies to increase soundproofing performance

The last element for soundproofing. If we could reduce the drywall from vibrating in the first place, it would make the jobs of the mass, the insulation and the decoupling easier and much more effective. After all, standard drywall is a HUGE surface area that is vibrating.

There are several products available that damp drywall. The highest performance for the lowest cost is Green Glue. Used between standard drywall, plywood, or subflooring, Green Glue damps a higher amount of vibration than any other material available.

Adding Green Glue to your assembly will increase soundproofing performance

Damping the drywall on the sound producing side of the wall reduced all vibration immediately. Again, the decoupling, absorption, and mass all have less of a job to do, resulting in significantly improved performance.

Find it all at:

Prince Lumber

 

SOUNDSTOP  wood fiber sound board that is a high-quality, cost-effective solution to all sound deadening, soundproofing, or sound insulation needs. These acoustical panels come in 1/2″ 4′ x 8′ sheets and can be used in homes and commercial buildings where airborne noise and sound transmission from room to room needs to be eliminated. The product also blocks outside noise from heavy traffic, blaring horns, airports, children playing, or other exterior noises that are a concern.

SOUNDSTOP takes shock or sound vibrations that travel through drywall and stops the movement of the sound or shock to the other side. The acoustic panel deadens sound transfer from shared walls, corridors, media rooms, workshops, etc..