- Hugh Davies
Electronic organ, based on a photoelectric principle, developed by Ivan Eremeeff at the radio station WCAU in Philadelphia about 1934. The single manual had a compass of 88 notes, and there were pedals for controlling volume and vibrato, as well as a decay control. Each key was attached to a shutter that opened when the key was depressed, allowing a beam of light to shine through two wide strips of film; one of these was marked horizontally and determined timbre (it was carried on rollers like a scroll and could be wound backwards or forwards, manually or by a motor, to change the timbre), and the other, which formed an endless loop, was marked vertically for pitch. These films, which were pre-recorded on Eremeeff’s ‘universal recorder’ using rotating tone-wheels, functioned as masks, in the manner of the optical film soundtrack; the principle of temporally separate stages for sound ‘programming’ and production is related to that of the tone-wheel organ and other instruments based on the techniques of graphic sound....