Lev Sergeyevich Termen most famous for creating the ‘Theremin’ also invented many other electronic instruments based on the heterodyning vacuum tube technology of the day – including the Keyboard Theremin, Theremin Cello, Terpsitone, Rhythmicon and the ‘Electric Harmonium’ or ‘Theremin Harmonium’.

Termen’s Harmonium was an early vacuum tube based polyphonic instrument designed to accompany vocal performances. The instrument had a three octave keyboard with a variable tuning that allowed 1,200 micro-tonal divisions per octave. The timbre and volume of the sound could be varied using twelve dials fixed to the front of the instrument.


does anyone know if an example of this instrument survived?
Hi – if anyone knows Andrei does:
http://www.asmir.info/
All the best,
Crab