To clarify for those who are not familiar with the Themodist system --
the accompaniment level is set by a single spring-loaded regulator
which normally serves the whole stack.  When a 'snakebite' comes along,
it momentarily opens one of 2 bypasses which divert the full reservoir
vacuum to either the bass or the treble section.  Since the pianolist
can control the full vacuum by pumping, the accented note's volume is
under full dynamic control.

The difficulty is that there is always a problem with the majority of
notes which are not accented.  The regulator attempts to keep them at
a constant volume, which is inappropriate for 'real' music.  If one sets
the spring too weak, the accompaniment is wimpy, when 'exciting' music
is attempted.  Also the 'droop' in the regulator (the fact that a spring
regulator has to open farther on lots of notes, shortening and weakening
the spring) causes big chords in the accompaniment to drop out
altogether.

If the spring is set too strong, there is not enough differential
between accompaniment and theme notes on softer passages.  There are
lever-controlled shutters in parallel with the snakebite actuated theme
valves which enable the pianolist to increase the base level, sort of.
But since this flow is unregulated, they don't work worth a damn to
maintain a constant, but lower, accompaniment level.

The following experiment would be worth doing, since it does not require
going inside any of the components:

 [ Richard gave a lengthy description of how one might add external
 [ components (a small pneumatic and springs, etc.) to the existing
 [ regulator; it will appear in a subsequent Digest.  -- Robbie

Richard Vance