On Aug 15, 2:24*am, "Robert Green" wrote:
I want to truly silence my Hayden central vac. *I bought a muffler for it,
but it's not really of much use since I've already vented the exhaust to the
outside via an unused dryer vent. The facts are that it's a high RPM motor
and it whines and wakes people up when it's in use when someone's sleeping.
My plan is to box it inside something lined with acoustical foam and to
provide two auxilliary fans (one low mounted push, one high mounted pull and
thermal monitoring) to keep the motor cool and shut if off if the
temperature in the box gets too high. *I know the motor's got a built in
thermal shutoff, but since I am going to be running it in an abnormal
environment and what a replacement costs, I'd feel safer with two.

I am going to make some preliminary and crude sound measurements wrapping in
a different material to see if any has particularly good sound deadening
properties. *Anything I am missing? *What sort of materials (I was thinking
3/4" ply and that bumpy acoustic foam) should I use? *How much distance to
leave around the unit for good airflow? *What CFM rate? *What sized fans? *I
intend to use 120MM 12V PC case fans, but I'm worried that a lot of sound
will leak out through the fan ports. *I thought perhaps "top hatting" them
the way chimneys and vent pipes are covered would reduce the leakage,
especially if the cap had some acoustical foam facing the fan.

Any thoughts appeciated. *Any flames will be cheerfully ignored!

Bobby G.

Google motor and music studio sound proofing for ideas, the common way
to do music studios is a seperate wall of maybe 1" or more drywall
both sides with fiberglass batts, but it floats it doesnt touch the
other wall and its on rubber pads, moving it off the mounting you have
now may have a giant effect from stopping vibrations through block.
Sand inbetween 2 sheets of drywall is used for machinery, even an old
Bass amp of the 60s had sand. There is alot you can do cheaply, even
experimenting with hanging some carpet around it will let you see to
be its effect now so you can gauge results, who knows , an isolation
mount and carpet might do it. Radioshack sells cheap and good "db
meters" to measure sound volume.