"Robert Green" wrote in message
...
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.

Make sure your box will come apart, so you can empty the thing