Hi All,  I have completed the restoration of my Steinway LR Duo-Art and
am now evaluating its performance.  One of my chief desires is that it
play soft, particularly on regular 88-note rolls.  (Playing a Duo-Art
roll softly is mostly under the control of the roll coding so what you
hear is what you get!)  During testing, I first set the player up so it
would play one note at about 5" of vacuum (per the test roll), but as
soon as you play a real roll, that delicate setting is of no value.

It seems that the system is so dependent on the quantity of vacuum needed
to operate the number of pneumatics called for at any one time that
dramatic changes in the number of notes being played (i.e., calling for
a different quantity of vacuum) results in very noticeable changes in
sound output from too loud to complete drop out.  Even while operating
an 88-note roll at a higher vacuum setting, the same problem is there,
it is just not so noticeable.

This problem also occurs to a much lesser degree even when playing a
Duo-Art roll, although I expect the roll expression coding was done in
such a manner to compensate for changes in the number of notes being
played so as to give  an end result that was equivalent to the original
recording.

So here is my question.  To prevent undesired changes in sound output
(vacuum level), the _Ampico_ system has bass and treble "action
equalizers" (reservoirs) connected onto the supply tubes leading to the
bass and treble sides of the stack, to presumably compensate for
significant changes in the quantity of vacuum needed at any particular
moment.  Even every "pumper" has a reservoir, as well.

Would adding Ampico-style bass and treble action equalizers to a
Duo-Art system destroy the expression (by presumably smoothing out the
changes in vacuum levels)?  Has anyone ever tried it?  Yes, I know it
is not original (but it would be reversible).

Thanks for any thoughts and advice.

Pat DeWitt
Fort Wayne, Indiana