I smiled after reading Eric Bergstrom's comment that "the best way to
quiet the system is to put the pump in the garage and run forty feet of
hose to the piano!"

Some years ago I installed a central vacuum in my home.  I learned the
art of running vacuum line.  I then decided to move my PPC to the
basement garage and use a similar method for the piano.  I can assure
you I hear NO motor noise.

Now, I know not everyone can do that, but in my case it was not
difficult, and it does work well.

Alan Wallace