Technical Sound-Image Transformations

3 Optical Sound Instruments

Recording technology is subject to the logic of the reversibility of recording and playing. The fact that the optical sound track is equivalent to the electro-acoustic signal makes it possible to synthesize sounds by means of tracing the appropriate wave forms directly or exposing them onto the sound track through stencils. As a result, optical sound as a photoelectric sound synthesis process was not only relevant for the development of the sound film but also played a significant role in the construction of different electronical musical instruments. In most cases, the sound was generated using the wavetable-synthesis method[7] via concentric, rotating perforated discs or partially darkened panes of glass, which modulated the light that lands on the photo cell. In the late 1920s and early 1930s, a whole generation of electric organs was created based on this method. This includes for example the Cellule Photo-électrique (1927) made by Pierre Toulon and Krugg Bass, the Superpiano (1929) created by Emerick Spielmann and finally, Edwin Welte’s Lichttonorgel (1936). In addition, Yevgeny Sholpo’s Variophone (1932) and Daphne Oram’s Oramics (1959) are techniques that use the exposed celluloid loops and sound generators.

In this sound generating process that is today frequently produced using synthesizers, a wave form is elicited as a loop from a wave table and transmitted as variable tone pitches by means of different reading speeds.