Hi All,  I've contacted the manufacturer that Jon Page mentioned to
find out which of their products would work best.  I think they will
suggest covering the suction box with Acoustiblok.

While that will probably reduce the actual motor noise significantly,
I don't think it will reduce the moving air noise created by the air
moving across the turbine blades.  As I demonstrate in my YouTube video
(at the link below), the majority of noise that's heard is a result of
the leakage in the player mechanism.

  http://www.youtube.com/watch?v=9vjKXLxxngA
 

I've thought of creating a baffle or muffler that can be placed between
the exhauster assembly and the pump.  This would help prevent the noise
from traveling up through the vacuum supply hose and into the exhauster
assembly.

Musically,
John A Tuttle
Player-Care.com
Brick, New Jersey, USA