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How do I build a noise cancelling box? Answered

I have a small water pump in the basement that creates a lot of noise that can be heard in most of the house. Is there a way to at bulid a 4 side + top box that really works to cancel out at least some of the niose? What materials works best as noise cancelling?




. My first suspect is a misalignment between the motor and pump. Not only does this make noise, it shortens the life of seals and bearings.
. Second guess is a bad seal or bearing.
. The impeller may be imbalanced. This can happen if algae and/or minerals have built up. A good soak in vinegar and a wire brush should remove all that.
. While a lot of noise can be transmitted via the piping, if you take care of the first three items, that shouldn't be a big problem. Isolating the motor and pump base from the foundation will probably help more than trying to isolate the piping.

.  PS: enclosing the motor in a box that is insulated well enough to block the noise will probably also block air flow and cause overheating.

What kind of noise is it ? low frequency, or high ?


I tend to agree with Ork, this is coming through the pipework I suspect. You need to isolate the vibration somehow. One way would be to put flexible connectors to the pump and the house.

What happens to the perception of the noise, if you hold the pipes firmly and someone else listens ?


You can build a box out of plywood or particle board. Then line it with foam rubber, old carpet, fiberglass insulation, old blue jeans, accoustic ceiling tiles, foam wall insulation anything like that will absorb lots of the sound.

Set the box on foam rubber to insulate it from the floor. Don't let it touch the walls.

If the pump runs very long it may need provisions for cooling.

Some of the materials mentioned are a fire hazard so you need to make provisions for that.

Sounds like you don't want noice _cancelling_ (which is complicated), but simply noise insulating.

To block sound you want mass that doesn't conduct sound, and you don't want paths which bypass the mass. One traditional sound-studio technique is sand-filled walls, preferably with offset studs so no stud contacts both wall (which would provide a path for sound to bypass the sand). But that may be overkill for your case.

But frankly, for high-frequency noise, I suspect just about any box will cut it down considerably.

Note that this only works if sound is not being conducted out via pipes or other resonant structures. If that's happening, you may need to mechanically decouple the pump from the house via flexible piping... and even then the water itself will conduct some noise; eliminating that seems likely to be complicated.