Hi All,  In his continuing effort to help people understand how
the Ampico system actually functions, Craig Brougher has written an
article called "The Ampico Crescendo System".  The article focuses
on the often misunderstood purpose of the crescendo device and how
it is used in conjunction with the intensity pneumatics to control
the expression of the music.

This article is very technical in nature and goes into great detail
about the logic that the designers used to create a smooth expression
curve that could be adapted to any size piano.  You'll want to read
this article more than once.  It's located at

  http://www.player-care.com/ampico-crescendo-system.html 

Musically,
John A Tuttle
Player-Care.com
Brick, New Jersey, USA