I read and re-read Richard Vance's excellent article on valve gap theory
several times, enjoying ever-increasing understanding.

As a small addendum, I have observed that, on some players, the
atmosphere-side valve opening is larger than the supply-side opening.
I presume that this is to assure that, whatever restrictions might be
made on the closing of the pneumatic by limiting valve travel (within
limits), the re-entry of air and re-opening of the pneumatic happen as
fast as possible to optimize repetition.  I believe this is consistent
with Mr. Vance's thoughts.

Cheers

Doug Rhodes

 [ Richard, do you have a mathematic model of the valve, pneumatic and
 [ action which could be used in a dynamic computer synthesis? -- Robbie