Robbie wrote, "I'm skeptical that the Stewart piano is really a new basic
concept -- it's probably just 'quiet', and 'low bearing'".

The Stewart design is different.  As Michael Waters wrote, he has changed
the design of the bridge pins so that the strings travel over it in a
straight line.

That is, the bridge pins are not offset relative to each other in the
horizontal plane.  The string passes into the new "bridge pin" in a
straight line.  This allows the string to vibrate in the vertical plane
for longer.  The normal bridge pin causes the string vibration to shift,
over time, from the vertical plane (the plane in which it is struck by
the hammer) to the horizontal plane, creating a circular motion.  The
relatively disorganised vibration is what causes the sound decay.  With
the vibration in a plane vertical to the sound board the energy is
maintained for longer.

I, too, saw the video clip mentioned by Michael.  There was a greatly
sustained sound which is quite dramatically different, even with limited
audio bandwidth.  I can't wait to hear it in real life.

Merry Christmas,  Peter Braun

 [ I can't wait to hear it, either -- up close!  I don't trust TV
 [ audio any more than I trust the facts in TV video clips!
 [ -- Robbie