Optically Reading Music Box Discs
By Jack Kane
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
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(Message sent Tue 6 Aug 1996, 11:57:49 GMT, from time zone GMT-0500.) |
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