The lab bench shown in the first photo occupied one corner of the bedroom in my newly-occupied apartment in Watertown, Massachusetts. This photo was taken in July, 1973, shortly after I had the hardware functioning normally.
Music data was stored on reel-to-reel tape, and recorded digitally using special record and playback head drive electronics I designed for the purpose. Lacking sophisticated instruments or equipment, the data rate was very low, but fast enough for the intended purpose. During playback, the audio head would pick up the digital data as rapid bursts of a zipping sound which could be suppressed when performing music. The tape recorder had a solenoid attached to the Pause button so the control electronics could start and stop the tape advance as demanded by the performance.
The digital control circuits captured data coming off the tape, decoded it into a note number and key code, and then activated a transistor drive circuit which turned on the appropriate oscillator in the organ. At the time this Gulbransen organ was made (1960s), each note had its own tuned LC oscillator (an inductor, capacitor, and transistor amplifier). A screw adjustment on the inductor, akin to the control rod in a nuclear reactor, permitted the circuit to be tuned to a particular note. It had a very pleasant, sinusoidal sound and was actually quite agreeable to the ear.
The vast majority of the circuitry seen in this photo was not involved in music playback, but rather in recording, editing, and various support functions (like the record and playback head circuits). Not shown is a key encoder used when recording music (built into the organ) and a note on indicator consisting of 60 miniature incandescent lamps arranged in a matrix 12 lamps wide by 5 rows deep. Each lamp corresponded to one oscillator on the organ and would turn on when that note was sounded. I intended this to assist in debugging, but as it turned out, offered quite a dazzling display of light patterns during normal music performance.
I paid $400 for the organ (I remember this clearly), and probably $500-600 for all of the parts (a bit uncertain about this because the parts were purchased over a period of months). Each green circuit board seen standing on end I designed originally on vellum paper using a Rapidograph ink pen (no CAD packages at that time), created a film negative from that, and exposed and etched a single-sided circuit board in a darkroom (something I set up in a spare closet in the electrical engineering department of Villanova University, my Alma Mater).
Music was very difficult to enter in this machine. I first transcribed the music I wished to record onto staff paper, divided the music into "note words" where each note word demarcated one change of state in the note activation, and then when this was complete, moved over to the organ and pressed individual keys to load each note and record it on tape. A separate pushbutton pad was built for the bass pedal notes. The process was similar to writing microprocessor programs in binary assembly language (no assembler software, linker, or loader). Approximately six hours of transcription and loading was necessary for each minute of performed music.
The music was separated into right and left hand parts, with groups of keys in the upper and lower keyboards triggering separately each part. Perhaps the biggest challenge in the initial, unpracticed performance involved keeping synchronization between left and right hand parts. However, once played through a couple of times, maintaining synchronization proved no problem.
A selection from Anna Magdalena Bach's Notebook was the first piece coded and performed, and because of its simplicity and popularity, became the default piece people tried when they played the device the first time. I also encoded the Toccata and Fugue in D Minor of Bach, one of Bach's trio Sonatas for Organ, one movement from a Violin and Harpsichord sonata, various other baroque compositions, and a couple of short contemporary pieces. I found great pleasure in playing music on the device and, with periodic maintenance, kept it operating for about three years through 1976.
Between 1973 and 1976, I demonstrated it to over 100 people and witnessed reactions of awe, curiosity, puzzlement, fascination, indifference, and outright hostility. For the most part, keyboardists with practical sightreading skill saw no benefit in this technology and scoffed. Some others felt that the relief of the mechanical burden of operating the instrument also relieved the performer of his right to be called a musician. I disagreed, then and now. I could accept such criticism for reflection without doubting the value of this approach because, first, I myself obtained such pleasure in performing with it, and second, because a significant number of very smart, musical people whom I respected were as enthusiastic as I was about it.
If I had accomplished anything, it was to prove to myself that musicianship extends beyond the ability to manipulate the levers, valves, strings, or bows that control an instrument. Indeed, many people who have such skill demonstrate often that they lack utterly any musicianship. Heretofore, it had been impossible to demonstrate the converse, that is, that people without well-developed skill to control an instrument could express innate musical ability. I have now seen this phenomenon first hand.
Playing music in this manner did not in any way interfere with my ability to play the piano manually, or to enjoy it. It did, in fact, amplify my ability to perform new, complex music, and perform music that would otherwise be impossible to play with only two hands.
Following 1976, after an unsuccessful attempt to interest Baldwin Organ in commercially adopting this approach, I set it aside and did not develop the idea further. A patent issued in 1977 covering the technology after debating with the US Patent Office for three years. By that time, I became swept up in the microprocessor revolution moved on to other interests.
Casio stumbled upon my work in their 1981 attempt to patent their first miniature music keyboard which included a "one-key play" feature, as they called it. Following a failed secret attempt to purchase an exclusive license to my patent, they were discovered as the party of interest, and we worked out a license agreement during my 1982 journey to Japan.
Happily, others were to follow in independently discovering this approach and applying modern computer technology to its implementation. I wish to specifically acknowledge Stephen Malinowski's brilliant work in developing his Music Animation Machine which includes Tapper, a single key implementation embodying the basic ideas I developed previously, but adding touch control and vastly simpler entry and editing of music information. To this day, I enjoy performing with Tapper, and am always delighted by new music that Stephen sends me.