I do sandblasting and the blower I use to supply air to my blasting hood
is, I have been told, the suction device for the pneumatic systems used
at drive-in bank teller windows to transport the document tubes.  It is,
I think, a motor-mounted regenerative-turbine which has identical intake
and outlet ports.  Take your pick -- pressure or vacuum.

It is relatively quiet and very powerful, but the reason I mention it is
that the motor is totally enclosed and there are fins on the housing to
dissipate the heat.  A simple throttling mechanism could be adapted to
obtain the vacuum/pressure desired.  Other than this I can't comment on
it's suitability for Mechanical Music Makers.

One thing has just occurred to me, however:  standard 1- 1/4-inch
'corrugated' sump pump drain hose has a tendency to set up standing waves
that are so loud I must wear earplugs for that reason alone.  I haven't
discovered the key to eliminating or reducing this problem yet, and would
welcome any suggestions.  But in a very limited sense I do, already, have
my very own mechanical 'music' maker!  Johnny One-Note, indeed!  Best
wishes....

danz   (Maybe I'll start signing myself as danzon....)
Richard Danzey

 [ I once used a small (1/6-hp) regenerative blowed in lieu of a high-
 [ speed turbine blower. It's a marvelous device, and fairly quiet.  I
 [ bought one from the old-time Spencer 'Orgelblo' Turbine Co., which
 [ made organ blowers, but the small regenerative blower was made for
 [ them in Japan. ... Did you know that Charles F. Stoddard, the
 [ Ampico inventor, held many patents on the pneumatic tube system!
 [ -- Robbie