Soviet artist Arseny Avraamov produced the first hand-drawn motion picture soundtracks. This was achieved by means of shooting still images of drawn sound waves on an animation stand. (from umatic.nl)

Oskar Fischinger (22 June 1900 – 31 January 1967) was a German-American abstract animator, filmmaker, and painter, notable for creating abstract musical animation many decades before the appearance of computer graphics and music videos. 

Oskar Fishinger writes in 1932: "If you look at a strip of film from my experiments with synthetic sound, you will see along one edge a thin stripe of jagged ornamental patterns. These ornaments are drawn music -- they are sound: when run through a projector, these graphic sounds broadcast tones or a hitherto unheard of purity, and thus, quite obviously, fantastic possibilities open up for the composition of music in the future." more at center for visual music.

Optical sound is a means of storing sound recordings on transparent film. Originally developed for military purposes, the technology first saw widespread use in the 1920s as a sound-on-film format for motion pictures. Optical sound eventually superseded all of other sound film technologies until the advent of digital sound became the standard in cinema projection booths.

Most of the inventions that led to optical sound-on-film technology employed the use of an electric lamp, called an exciter, shining through a translucent waveform printed on the edge of a film strip. When the light shines through the film, it is read by a photo-sensitive material and fed through a processor that converts the photovoltaic impulse into an electrical signal that is then amplified and converted into analogue sound waves through a speaker.

Mariska de Groot is a Dutch artist who makes and performs comprehensive analog light-to-sound instruments and installations which explore the phenomena and history of optical sound. Her work often has a reference to media inventions from the past.

Mariska de Groot on Vimeo