Greetings Automusers,  As Robbie commented in MMD 030504, Welte had
a patent for an almost perfect system.  If Welte had added the Themodist
system to theirs it would have been perfect.  The Welte works with true
feedback and will maintain a set vacuum level in the stack with only
minor fluctuations due to program demand.  It is a fast regulator and
can be used to accent notes quite accurately but it still can not beat
the Duo-Art.

Aeolian had the Themodist system which worked very well for Pianolas in
which the expression was controlled by the person operating the pedals
and controls with the accented notes coded in the roll but not the
levels set.  The pianolist provided the feedback necessary to
compensate for program demand and could instantly and intuitively make
any adjustment necessary.

Aeolian attempted to extend their system to fully automatic regulation
as the Duo-Art.  The idea of two 4-bit binary codes to control the two
pneumatic regulators was excellent, but the execution was not.  If they
had hired a competent engineer at this point they might have produced a
system that did not place huge demands on the editors who were to
produce music for this system.  They also could have produced a system
that could last longer in spite of aging materials.  This was not such
a big problem in their time as they had excellent materials
specifically made for their needs.  This is not the case today and it
is a real problem for collectors and rebuilders.

It can not be expected that any manufacturer would be concerned with
the preservation of their products nearly a hundred years later.
However, if they had designed a more self-compensating system, this
would be less of a problem today.  In addition, they might have
produced even more music equal in quality to their best examples.

There is much Duo-Art music that falls short due to inferior dynamic
coding.  It must have been extremely difficult to learn to code Duo-Art
rolls.  Few people today do it well in spite of all of the examples
provided by past attempts.  In fact, I doubt that anyone coding rolls
today is aware of many of the subtle effects that may be obtained on a
system in perfect condition.  Unfortunately, they only work when the
system is near perfect and since that happens rarely, these subtleties
usually are not expressed.

Best regards,
Spencer Chase
Garberville, CA
http://www.spencerserolls.com/

 [ Indeed, the large pouch switch in the Themodist and Duo-Art
 [ expression box enables an extremely rapid suction increase for
 [ accenting.  I've heard that one of the rare European pianos used
 [ such a pouch switch and a "theme & accompaniment" design similar
 [ to Duo-Art, but otherwise the system used crescendo (rate) control
 [ like the Welte-Mignon.  Does anyone have more information?
 [ -- Robbie