Introduction
By Richard Tonnesen
-- [ From: Richard Tonnesen * EMC.Ver #2.10P ] --
Hello to all...
In keeping with the spirit of this list, I will briefly introduce myself. I already know many of you through AMICA, but this is a good forum to meet others with similar interests.
I joined AMICA in 1972 and bought a Weber Duo-Art grand a few months later. I started to look for a good way to apply computer technology to automatic music, either to preserving the music in machine readable files, or perhaps to operating a piano in real time from computer files. I quickly decided that it would be too much work, too expensive, and too inconvenient to have a minicomputer attached to a piano, so I started to consider building a computer-operated roll reader and companion punch. It took several years, but I designed and built a 100 channel roll reader based on pneumatic switches, and a 100 channel roll punch. Both were operated by a 16 bit minicomputer (one at a time) and used punched paper tape as an intermediate storage mechanism. The roll punch operates at 15 steps per second and punches 45 steps per inch. The reader operates at about two feet per minute. In the reader, the paper is driven by rubber covered capstans which generate a clock signal as they turn to provide equally spaced samples regardless of reading speed. The system was complete in 1979, and used an Interdata 7/16 minicomputer with 16Kb of core memory that I purchased at a bankruptcy auction. Late in the 80's, I converted the main logic of the reader control program to run on a Macintosh computer and converted the real-time part (scanning contacts and synchronizing with paper motion) to run on an Intel 8031 microcomputer. My main goal was to take advantage of disk storage instead of paper tape and to use the on- screen display capability to edit roll images. As the years went by, the Interdata machine failed and was beyond economical repair so I had to convert the punch program to the Mac. I got a second Mac so I could run the reader and the punch at the same time. I had initially written a primitive editor to run on the Mac, but recently have been using an editing program written by Richard Brandle of Dallas. The new program features conversion of the various reproducing roll data formats to MIDI output by emulation of the reproducing mechanism. This equipment and Brandle's program were used on the recent Gershwin CD by Artis Wodehouse.
Recently, I have been looking for ways to make the reading operation faster and more reliable. The pneumatic switches need about 5ms to turn on and 25ms to turn off. That causes elongation of the note holes in the copy if paper speed is any faster than about two feet per minute. The switches also tend to get out of adjustment. A few start to turn on too soon while others start to turn on too late. They can be re-adjusted but it is time consuming and exacting work, and really boooorriiinnnggg.
Roll reading is one of my favorite subjects. It seems to be very fashionable lately, but is harder than many seem to realize. What are the requirements for a transcription quality reader? How many samples per inch is enough? How fast is fast enough? How can you tell when you have a good file short of punching a new copy and comparing the original and copy end-to-end, hole-for-hole?
I will be looking for a few good ideas.
R.T.
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(Message sent Sat 22 Apr 1995, 02:28:37 GMT, from time zone GMT-0400.) |
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