Hugh Le Caine's Special Purpose Tape Recorders

In the 1950s, Hugh Le Caine, an engineering physicist working for the Canadian National Research Council, designed a ‘Special Purpose Tape Recorder’ for use in electronic music studios. It enabled composers to transpose, mix, and sequence sounds stored on multiple tapes whilst maintaining expressive control over pitch and dynamics (volume). The SPTR was novel at the time because it combined the functions of sound recording technology with the generative, expressive capabilities of a musical instrument, thus defining a new and (it turns out) enduring paradigm in creative music technology. This article outlines how the SPTR came into existence and developed, drawing on archival sources and analysis of surviving prototypes and ancillary instruments now held in the collection of Ingenium: Canada's Museums of Science and Innovation.