I truly hope my comments about the Duo-Art opens up some comments
regarding the changes in the system over the years.  Cross valves
were introduced and then replaced, there were different types of
expression boxes such as the "fan" model, and different sizes of the
expression boxes (Steinway and Weber pianos have larger boxes than
others -- why?), and there was the Tempomatic knob verses the levers
-- how do you use the levers when playing a roll?

The Duo-Art was a really nice system that has had some great articles
in the AMICA bulletin: the construction of the XR verses the M model
Steinway, the OR verses the O model Steinway (when did they change to
the L series?), the AR verses the Model A Steinway.

There were several different model A Steinways.  Did all the AR
Duo-Arts use the same plate, or was just the case made different?  What
about the braces under the soundboard?  Did that rearrangement affect
the tone of the piano?  How?  Did you ever notice that the ivory keys
on a Steinway are a bit wider than other brands?

This should light up the pages of the MMDigest.

Don Teach - Shreveport Music Co.