4 Basic Ways to Improve Sound Isolation / Soundproofing Performance
Now that we have taken a look at the The Five Basic principles of Soundproofing / Sound Isolation (if you haven't seen that page, take a look), we can take a look at the things that improve them. We'll call these areas of improvement, and we'll talk about your options in each area.
1. Increase the Mass
Adding more mass to the wall helps. To make a BIG improvement, you have to make a BIG change in mass. For example, to improve sound isolation by about 10dB you would have to quadruple the number of drywall layers on your wall - from one each side, to 4 on each side. Mass makes a much larger improvement when combined with other techniques. Related Article: The Sound Absorption Properties of Walls
2. Decoupling
When building a new wall, opt for (in order of effectiveness) double stud walls, staggered stud walls, use sound clips or spring ceiling hangers, or resilient channel. To better understand each of these options, you can click on our Wall Type Design Sheet, which shows assembly details of each. When using decoupling, you should understand that adding mass has a large effect on low frequency performance. As a result, the effect of adding mass to a decoupled wall is much larger than that of adding mass to a conventional wall. Related Article: Understanding How Decoupling Works
3. Absorption
If there is no insulation in your walls, add some. This will help only slightly if the drywall is not damped or not decoupled, but can still help. The rule of thumb with insulation is to make sure and at least use some. For example, in a ceiling by far the biggest gain is going from no insulation to a thin insulation - say R13 fiberglass batts. Additional improvements are seen from using R19, or even thicker, but these are progressively smaller, and generally don't help with low frequencies. Use something, but you can save yourself money by not spending exorbitantly on extremely thick insulation or exotic types. Better yet, take the money you saved, and put it towards something else (like one of the other 3 areas of improvements). In general, anything thicker than R19 is into the realm of diminishing returns. Related Article: Sound Absorption of walls
4. Damping
You can improve the damping of your construction with products such as Green Glue, or factory-damped drywall, etc. Damping works on two of the principles above - resonance and conduction. It reduces the severity of resonance problems, and it reduces the ability of structures to conduct vibration.
About Damping, Effects of Damping, Soundproofing Damping Options & Performance
Interacting principles
These 5 principles, and 4 area's of improvement, are interactive. For example, adding mass might change resonant behavior by shifting it down in frequency (for some walls). Decoupling also changes resonant behavior, as does the inclusion (and type) of absorbing material. Related Article: "About Damping"