I have a 5'9" Young Chang grand piano with PianoDisc 128+.  I am happy
with the unit, with one exception: the sustain mechanism is operated
with a solenoid-activated lever.

When the solenoid engages it pushes down on the lever which pushes up
the dampers.  When the solenoid releases, the dampers return to the
strings with a "clunk."  This is because the solenoid releases all at
once, whereas a human pianist releases the sustain pedal quickly but
gently.

I think I have found a solution for this problem.  I installed a
miniature shock absorber about 2 inches from the solenoid plunger,
to dampen the return of the lever.  It is 4-1/2" x 3/4" with fully
threaded body, which makes it very easy to install and adjust.
The unidirectional, adjustable shock absorber is manufactured by
Ace Controls, Inc.

I used a model MA 225 shock absorber (about $38) with a model 250-0401
mounting block (about $15).  The rod has a 3/4" stroke (my mechanism
needs 1/4") and 1/10-second return time.  I installed it with the rod
end touching the lever.

When the solenoid pushes the lever down the shock absorber rod remains
in contact with the lever without any interference.  When the solenoid
releases, the shock absorber softens the return of the lever enough to
permit the dampers to return to the strings quietly.

If anyone has a similar problem, you can order a catalog from the Ace
Controls web site:

    http://www.aceshocks.com/

I e-mailed PianoDisc about this and await their comments.

Mike Ryan

 [ The Ace Controls web site is interesting.  I had no idea that such a
 [ wide variety of linear damping devices existed.  I'd be interested
 [ to know what others here think of these devices for this application,
 [ or others like it.  -- Jody