The optical sound organ uses photoelectric sound generation . The sound generation was controlled with glass, rotating "clay discs" in front of photocells . Vibration curves that were recorded from original sources and graphically reworked were transferred to the clay discs coated with a photo emulsion. The tones were then played through amplifiers and speakers . The recording technology was largely clarified on the basis of the archive material in the Augustinian Museum as part of a research project at the Technical Museum Vienna .
Edwin Welte resigned in 1931 from the family company M. Welte & Sons, which was in financial difficulties, was founded in 1832 and has been based in Freiburg im Breisgau since 1872 . When exactly he began developing the optical sound organ is uncertain. In any case, he acquired the rights to a patent registered by Richard Michel from Monaco in 1925 (DRP 443535) for a “ keyboard instrument for generating music electronically”. From around 1933 Welte had been experimenting with the organ builder Aug. Laukhuff in Weikersheim / Württemberg together with the organ builder Wilhelm Faass with the aim of building a functional prototype.
The Theodor Mannborg harmonium factory in Leipzig was also involved in the development , and a cooperation agreement was signed with the Telefunken electronics company . In 1935, Welte registered another patent of its own for the optical sound organ (DRP 712570), a process for producing phonograms representing mixed voices on sound discs for optical sound organs .
At the end of 1935 Mannborg had finished a series-ready example of the organ with 16 sounding parts and 24 stops. It was performed in a press concert on August 17, 1936 in the skylight hall of the Berlin Philharmonic . The press response was very positive. On November 6, 1936, the organist Kurt Grosse gave a concert on the optical sound organ, accompanied by the cellist Armin Liebermann. The reviews in the press were again favorable. For example, the party organ of the NSDAP , the Völkischer Beobachter, wrote on November 9, 1936 of Edwin Weltes “a unique marvel” as a “concert instrument that encompasses the entire realm of sound in its perfection”. Welte was now hoping for orders. Its organ offered almost unlimited amplification with little space requirement and thus seemed to be made for the mass events of the " Third Reich ". In addition, his instrument seemed to have the advantage that, in contrast to the Hammond organ that had been offered since 1935 and sold very successfully, it was a German product.
But apparently the personal circumstances of Edwin Weltes had been checked in Berlin before further cooperation. It was found that he was married to a Jewish woman. The National Socialists then dropped him, and Telefunken withdrew from the cooperation agreement without giving any reason.
During the Second World War hit Friedrich Trautwein Edwin Welte for the development of a blind reading machine from the pneumatic based technology for the Welte-Mignon - Reproduction piano based. However, this did not get beyond the planning stage, as both the Welte company buildings and the university institute involved were destroyed in the bomb attack on November 27, 1944 .
The only existing optical sound organ was destroyed in 1945 by the effects of the war at Aug. Laukhuff in Weikersheim. All attempts by Edwin Weltes to make his optical sound organ a success after the war were unsuccessful. The technology used was now out of date. However, the merit of Edwin Welte is based on the first use of sampled analogue sounds to reproduce the tones.
The construction plans and numerous parts are now in the Augustinermuseum Freiburg.
- John Eggert ; Richard Schmidt: Introduction to Sound Photography. Photographic basics of optical sound recording. Leipzig, S. Hirzel, 1932
- Fritz Fischer; Kurt Grosse: The Welte-Lichtton-Organ. A church and concert organ, the sound of which is generated not by whistling and reeds, but by electro-optical means. E. Welte, Freiburg (Breisgau) 1935.
- Werner Lottermoser : The optical sound organ by Edwin Welte. In: Acoustic magazine. Volume 1, No. 3, 1936, , pp. 193-194.
- Fritz Stege : Sounding light. In: magazine for music. Volume 103, No. 10, October 1936, , p. 1235.
- Hermann Matzke : Two German electro-acoustic organs. A first finding. In: Zeitschrift für Instrumentenbau . Volume 56, No. 24, 1936, , pp. 404-405.
- Robert L. Eby: Electronic organs. A complete catalog, textbook and manual. van Kampen Press Wheaton IL 1953.
- Hugh Davies: A history of sampling. In: Organized Sound. Volume 1, No. 1, 1996, , pp. 3-11, here pp. 6 f.
- Michael Gerhard Kaufmann : Organ and National Socialism. The ideological appropriation of the instrument in the “Third Reich” (= series of publications by the Walcker Foundation for Organ Research. Volume 5). Musikwissenschaftliche Verlags-Gesellschaft mbH, Kleinblittersdorf 1997, ISBN 3-920670-36-1 (At the same time: Karlsruhe, University, dissertation, 1997).
- Peter Donhauser: Edwin Weltes Lichtton-Organ. In: Gerhard Dangel (Red.): From Freiburg into the world - 100 years of Welte-Mignon. Automatic musical instruments. Augustinermuseum, Freiburg (Breisgau) 2005, p. 158 ff.
- Peter Donhauser: Electric sound machines. The pioneering days in Germany and Austria. Böhlau, Vienna a. a. 2007, ISBN 978-3-205-77593-5 .
- Items. In: Freiburger Zeitung , September 20, 1936 (Sunday edition), p. 3
- Welte-Mignon-Portal for mechanical musical instruments
- Musical instruments department. Technical Museum Vienna