Greetings,  In the continuing effort to understand the operation of
reproducing pianos, I have been looking at the timing of notes in
piano rolls.  I have been using e-rolls so that the data can easily be
collected and examined.  It is much easier that taking measurements
directly from rolls.

There was a published standard (1911 if I remember correctly) as the
result of a conference of piano roll manufacturers in which it was
agreed what spacing between notes was supposed to represent a
reiterated note.  I forget what the figure was and it is not a hard and
fast rule, due to the contribution of several factors to repetition.

WindPlay uses this rule and marks suspicious notes.  It is a convenient
way to visually check a file but is not the final word as vacuum and
duration of notes also effects the repetition rate.

I have also written a program that lists the inter-note spacing in a
text file and have been looking at a lot of files.  I have my ideas as
to what will reliably repeat and what will not but would like to hear
from others especially since these rates may vary from player to
player.

My program list time in milliseconds between events but this can easily
be converted to distance at any fixed tempo.

What do others think, is the time (or distance of paper travel at a
specified tempo) required for a stack valve, pneumatic and piano action
to reset between repeated notes at average vacuum?  The time is less
for staccato notes since the pneumatic may not collapse completely and
will require less time to reset.  Gaps between extended adjacent notes
will need to be longer.

Best regards,
Spencer Chase
Laytonville, Calif.
http://www.spencerserolls.com/