Hugh Le Caine had heard radio broadcasts of tape music since the early 1950's and he had worked extensively with tape reverberation, feedback and multi-track recording. After the NRC programme in electronic music began, the focus of his instruments shifted from performance to composition.

This 1957 photograph of the prototype Special Purpose Tape Recorder shows the six reels of tape playing simultaneously, the keyboard with which the playback speed was controlled, and a series of tape loops hanging above the instrument.

He began to work on a device which he called the "Multi-track" to alter the playback speed of recorded sound, which would facilitate the use of recorded sound as a compositional material. By 1955, the first prototype of this new instrument was able to play six tapes simultaneously, changing the playback speed of each tape independently and recombining the resulting sound into a single recording. The tapes were played on a single capstan at the left of the instrument while the speeds were controlled by a three-octave keyboard on the right.

Volume was controlled in six groups by six touch sensitive keys. Later, with the assistance of Gordon Ellis and Horace Aubrey, the instrument was expanded to play ten stereo tapes and produce a stereo output. The instrument was actually more of a multiple tape player than a tape recorder though it was formally called the "Special Purpose Tape Recorder."

Below:

• The 1955 Prototype
• The Special Purpose Tape Recorder at the University of Toronto
• The 1961 Model
• The Special Purpose Tape Recorder at McGill University
• The 1967 Model

Le Caine expanded a multi-track tape recorder he had built in his home studio, and in 1955 installed a variable speed control for the playback mechanism. That fall he composed his landmark "Dripsody" using the new multi-track Special Purpose Tape Recorder.

The keyboard of the 1955 prototype.

The central instrument in the studio at the University of Toronto was the Special Purpose Tape Recorder. When the studio opened in 1959, it was the first in Canada and the second in North America. Myron Shaeffer, the studio director, designed and built the Hamograph to control the Special Purpose Tape Recorder.

Myron Shaeffer, in 1964, at the console the Special Purpose Tape Recorder; to his right is the Hamograph.

After the Edward Johnson Building was opened at the University of Toronto, the new electronic music studio in the basement was equipped with two work areas. A second and greatly refined Special Purpose Tape Recorder, (here demonstrated by Gordon Ellis, Le Caine's assistant at the National Research Council) was installed in the second work area.

Gordon Ellis at the keyboard of the 1961 version of the tape recorder.

Hugh Le Caine (center) demonstrates the internal controls of the 1964 version of the Multi-track Tape recorder to Istvan Anhalt (left) and Helmut Blume (back) of the Faculty of Music of McGill University.

The McGill Studio was well established by 1968. The adjustable filter is in the foreground, the Multi-track Tape Recorder at left. Istvan Anhalt is shown using the Spectrogram with the Oscillator bank at the rear.

Hugh Le Caine plays the last and most compact of five Special Purpose Tape Recorders at the National Research Council lab in 1967. Printed circuit keys were used to control speed changes of the tape.

Six stereo tapes playing on the common capstan of the Special Purpose Tape Recorder.