Electronic Musical Instrument 1870

The Sphäraphon range of electronic instruments was developed by the musician Jörg Mager specifically for microtonal music in Berlin from 1921 to 1928. The initial instrument, the "The Electrophon", built with the assistance of the electronics company Lorenz, was a heterodyning tone generator based instrument. The Electrophon was controlled by a handle that the player moved across a marked semi-circular dial creating a continuous glissando effect. The Electrophon had no manual keyboard control.

The Kurbelsphäraphon was an improved Electrophon with a added filters to improve the timbre and to avoid continuous glissando the KurbelSphäraphon had two switchable tuning handles used in conjunction with double foot pedal to control the volume. The KurbelSphäraphon was completed in 1923 and presented at the Donaueschingen Festival in 1926 where it was mostly ingored. The composer Georgy Rimsky-Korsakov (Grandson of the Russian composer) composed some quarter-tone experimental pieces for the instrument.

Supported by the city of Darmstadt (the Heinrich Hertz Institut für Schwingungsforschung and the Reichsrundfunk radio station) and with the assistance of Oskar Vierling, Mager continued his work on his instruments creating the Klaviatursphäraphon in 1928, replacing the handles of the Kurbelsphäraphon with two short keyed monophonic keyboards - the shorter keys allowing the player to play both keyboards simultaneously thereby producing a duophonic tone. It was also possible to tune the keyboard to microtonal tuning. Additional tone colour was added by mechanical resonators and specially formed speakers.

The "Partiturophon" was a four (in later models, five) keyboard and five voice version of the Klaviatursphäraphon produced in 1930. This instrument allowed the player to play four (or five) voices at once, one voice per keboard:

"Mager produced today and organ with many registers on which four voice playing is possible. So far there is only one difficulty; that is, that each voice must have its own keyboard, thus the four voicemovement must be played on three manuals and the pedal. For this reason the manuals must be close to each other and the keys short, so that one can easily play on several manuals with one hand. For thgis reason the keys are somewhat narrower than those on aregular organ or piano keyboard. Apart from these difficulties, which require a special adjustment to the playing of the new instrument, it is suprising in its infinite multiplicity of sound possibilities, through dynamic wealth of shading and through the possibilities of expression in the tones"

Frederick Prieberg

The "Kaleidophon" was completed in 1939 and although its history is undocumented is described as "an electronic monophonic instrument with "kaleidoscopic" tone mixtures" the instrument was built influenced by the tonal ideas of Arnold Schoenberg and Ferrucio Busoni.

Magers instruments were extensively used mainly in theatrical productions in Germany though none are known to have survived the second world war. in 1929 Mager was given the use of a small castle in Darmstadt where he founded the Studiengesellschaft für Elektro Akustische Musik.