I recall seeing an unrestored Soloelle system piano.  The instrument
was a Knabe upright made in the 1920's.  I was expecting it to be an
Ampico but it was more like a standard player.  The Soloelle mechanism
was an expression device built into the hammer rest rail.

The rail was cut into approximately ten sections.  Each section was
hinged independently to pivot foreward toward the strings to reduce the
blow distance.  Pneumatics were connected by a system of cords and
pulleys to each section of hammer rest rail.  I assume that the Soloelle
code in the rolls would specify certain sections of hammers to pivot
forward at specific times to soften the blow, and thus give dynamic
variety in different pitch ranges to a song.

During hand playing of the piano, the hammer rest rail moved all the
sections in unison toward or away from the strings in the normal
fashion.

Since Knabe was an Ampico product, and as Mike states--"These rolls
would play on my Ampico with rather limited expression."-- could this
perhaps be a poor-man's reproducing system that was Ampico compatible?

The instrument belongs to a family friend in Stockton, California.  If
there is enough interest, I could probably get photographs of the
mechanism.

--Erik Siverson--