Sub Woofer vibrations

[frankvig]

I installed a sub in my sons room on the third floor of our house and the whole house vibrates to the point were we can't hear our TV or music. It's not so much the volume but the vibrations. The sub's speaker faces down. My question; is there a mat or anything I can do to help this?

[biff]

Just for experimentation, try folding a towel and placing it under the legs. If that has some effect, then you can work on refinements - however, sound does tend to travel down in a structure. The same things that work for turntables work here, and experimentation will payoff. Try a slab under the sub with half tennis b*lls between slab and floor. The ultimate would be to suspend the sub from the ceiling, or ropes, etc hung from a wall bracket. You just want to decouple the physical vibrations from the house. You (he) will likely notice a dimunition of the sub output, subjectively, as some of what is perceived as bass impact can be a physical vibration transfer similar to the principle of bass shakers. What you are left with will be more tuneful and less one note-ish than before and you should be able to have a higher level in the room and less transfer throughout the home.

[billfitzmaurice]

My question; is there a mat or anything I can do to help this?

Not really. Long wavelength low frequencies pass through all but the most robust floors and ceilings, not to mention doors. They also go around corners and obstacles, so shy of rebuilding the house there's not a lot you can do save teaching him how to make use of the volume control. Also investigate placement of the sub to maximize the volume inside the room where it's located, which actually will reduce its impact outside of the room. Corner placement is usually best. Boundary cancellation effects are explained at:
http://www.padrick.net/LiveSound/CancellationMode.htm

[mike1234]

Place the sub in the corner, as Bill said, that should help. If there's still an issue then try isolating the subwoofer from the floor with a concrete paver larger than the base of the sub box and use a partially inflated inner tube between the box and the paver. BTW, don't use a down-firing sub in an upstairs room if sound transfer is a worry.

There's a lengthy thread regarding this technique here in this forum... somewhere.

[philiparcario]

use a piece of butcher block cutting board with 4 hockey pucks. the hockey pucks run 1 to 2 dollars each. if you are in new jersey i have one butcher block setup in my attic collecting dust.