Certainly the tracker bar for optically reading a disc would not be a
straight line but rather an offset from the center.  This is not as
prominent on the played disc as on the master plate, but it is offset
nevertheless.  As to the speed of the notes playing at the edge of the
disc versus the center, there is a significant difference.  If the data
went into a Cakewalk file, perhaps the velocity of the note could be
adjusted in the programming of the output;  the trick would be how to
control the photocell so that it didn't "hang" due to the response from
the incidental light.

The data I would want from the disc is only the "start time" for each
note on the disc -- this is all that is needed to transcribe a disc to
another disc.  This would be great on the 17" Stella (84 notes) as it
is the same scale that is used on the 18" Mira (93 notes --the Mira has
two additional bass notes and repeat notes of others.)  Terry:  this
might be helpful in getting new tunes for your Kalliope.

It just occured to me as well that the disc projections (the tabs left
on the disc when punched -- these turn the star wheels that pluck the
comb) need not interfere with them being read by the photodiodes:
simply play the disc "upside down" and reverse the direction that the
disc is played (from clockwise to counterclockwise or vice versa,
depending on the original format.)

I've got a small Stella disc coming in the mail -- when I get it, I'll
forward a copy to Robbie.  Sounds like fun!

Jack