On Aug 15, 7:32*am, wrote:
On Aug 15, 8:20*am, ransley wrote:





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.

I would talk to Hayden , I bet they know what is most cost effective
and works. The Sound- frequency, frequencies, you are deadining have a
wave length that some materials absorbe better than others and foam
may not be as effective as something cheaper. An example of why you
only hear bass from cars or homes that are to loud is the wave of the
low frequency can be 3-4 feet long, and carpet stops the real high
frequencies *as they can be only 1/4" long. The frequency of the
whine, Hayden or a musician could figure out, then an enclosure needs
to be designed for that area of frequencies. I guess a 1" drywall box
with 6" fiberglass batts open to the motor might be better and cheaper
but i cant hear the vac from here, the fan idea and completely closing
it is risky, you cant rely on the thermal cutoff in their unit for
saftey. Maybe rubber mounting bushings of the vac would do alot as its
probably vibrating the wall.- Hide quoted text -

- Show quoted text -

Before I undertook all that work, I'd get a new, quieter unit. *I have
a 25 year old unit located in the basement and most of the noise in
the living space comes from the head unit that sounds similar to a
conventional vac, not the motor in the central vac.- Hide quoted text -

- Show quoted text -

Right I thought a main selling point is those were supposed to be
quiet, could the instal be bad? but I wonder if its really noisy.