The ‘Fotosonor’ was a photo-electrical organ built in France during the 1950s and was designed to replace a traditional pipe organ liturgical music. Several models of the instrument were built;
The ‘Choir Organ’ was a large traditional wooden panelled , two manual church organ. This modular version had up to eleven optical tone units – each unit reproduced the sound of a traditional organ; Drone, Flutes, Trumpets and so-on. The large tone units were housed in a separate moveable cabinet so that only the ‘traditional’ keyboard part of the instrument was visible.
The ‘Deux Jeux’ and Quatre Jeux’ were of a more modern metal-clad design each with two or four tone units respectively. In this design the tone units were integrated into the keyboard part of the instrument alongside an amplifier and loudspeaker system. The manufacturers also suggest that a turntable “…can be easily incorporated to accompany the organ, allowing the study of liturgical works in general; particularly Gregorian chant, choral singing hymns”
The pipe-organ sound of the Fotosonor was generated using a photo-electrical technique; rotating glass discs printed with looped sound-waves interrupted a light beam trained on a photo-electrical cell thereby generating a reproduction of the tone ‘recorded’ on the disc. This had the added benefit of the organist being able to ‘update’ the instrument with optical recordings of new sounds.
‘Fotosonor’ Promotional booklet. La Société Française Electro-musicale. 23 Rue Lamartine, Paris 9.