Why not place the blower remotely?   Back in the 1960's I had an
Ampico pump that knocked no matter what I did to it.  Finally, one day,
I placed the pump out in the detached garage and ran an underground
pipe to the house and into the piano.  It did not matter how noisy the
pump was, it sure was silent in the house.

Bruce Clark

 [ Vic Searle's Caliola-style organ is portable (like a Caliola),
 [ so a remote blower is not practical.  -- Robbie