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Showing posts from November, 2010

Mass is not enough

Can you block noise by adding mass? That depends on the situation. What kind of noise? How does the noise travel? What materials will you use, and how will you apply them?

This 2008 article from "Sound on Sound," explains that sound "cannot be destroyed: it can only be converted into another form of energy." While some sounds are airborne and can easily be blocked, you might still hear lower-frequency sounds passing through on the other side. This is because the energy from sound waves makes the walls vibrate, and this creates more energy.

Does adding mass help? Yes. Will mass solve all your noise issues? Possibly not. You might also need to address other characteristics of the space by adding sound absorption inside the rooms, or by decoupling the floors, ceilings, or walls from the structure to keep the sound (energy) from passing into it.

Let's look at a couple of examples.
Example 1: Interior doors Many American homes feature hollow-core interior doors. Th…

Someone else's QuietRock success story

This video is readily available on YouTube. In my own experience the QuietRock -- on its own, as replacement drywall -- stopped neighbor conversation at normal volumes and muted TV at normal volumes.
Even with the best drywall, a loud stereo with lots of bass might produce soft thumps, and direct impact against a neighboring wall (hammering, door slamming, etc.) might still come  through. But the noise is significantly reduced. One thing to consider in some instances: if you only soundproof the wall, but not your ceiling or your floor, some noise might come through in those untreated areas.
I agree that most construction -- at least in the USA -- is done cheaply without insulation and by using ordinary gypsum nailed right on the studs. I'm amazed when I see construction sites and see ordinary drywall getting unloaded!

Example: how wood turns vibration into noise

When noise becomes a low frequency vibration... I made this short video with my mobile phone to show how an airborne noise (the buzz from my mobile phone when it's set to "vibrate") becomes a loud, intrusive noise when it makes direct contact with a wood surface. This is the same way that simple impact noises like walking, opening and closing doors and drawers, or even the bass from your stereo or home theatre system can go into the walls and transmit to your neighbors or to other rooms in your home.

I placed different materials underneath the phone while it was buzzing on top of the wood table. You can hear how each of them (even the thin sheet of cork) make a difference in reducing the noise transmission through the wood.

One point: while I was recording this, I noticed that QuietRock (being the "hardest" of the surfaces) still transmitted a tiny bit of vibration to the wood beneath it, while at the same time dampening the buzz. That's an example of how …

A simple lesson about how sound bounces

Create an angle to reduce the "bounce" This short video from eHow shows how to build an effective, soundproof window in a recording studio. You'll learn how angling a surface (rather than using straight, 90-degree connections) helps to reduce sound transmission.

Notice how the glass for this studio window is inserted at a slight angle. This is a terrific lesson on sound transmission.