I have been following with great interest the discussion of perforator
step size.  During this discussion, nobody so far has mentioned the topic
of tempo compensation.  I'm sure everyone realizes that as a music roll
plays, the take-up spool increases in diameter, causing the paper to
travel faster towards the end of a roll.

I am now aware, by virtue of this forum, that Ampico paid great attention
to music roll accuracy.  I was sure that Ampico was well aware of
compensating for the change in paper speed over the duration of a tune.
So I did some investigation to see what they had done.  To my surprise,
all of the rolls I checked had the same distance between beats from the
beginning of the roll to the end.  These rolls were not tempo-compensated.
Or is there something else going on?  This sort of non-tempo-compensation
reminds me of my first hand-cut rolls.  Tempo compensation throughout the
duration of a tune is difficult and inconvenient to do by hand.

 -- Why didn't Ampico, with precision automatic perforators, compensate
the tempo?

 -- Do all Ampico pianos have a take-up spool with the same diameter?

The subject of perforator step caused me to do this investigation.  Rolls
produced by Wurlitzer are definitely tempo compensated throughout the
entire length of the music roll.  If you try to put a number on the step
size you will discover that the step size changes continuously, and there
is no number that you can assign to the step size. The distance between
beats on a roll produced by a Wurlitzer perforator will grow towards the
end of a tune.  I believe that the Wurlitzer perforator mechanism which
created the variable step size was described by Matthew Caulfield.

If someone has comments on why Wurlitzer tempo compensated music rolls and
Ampico seemingly did not, I would be very interested to know.

Sincerely, David F. Wasson