The Electronium was developed by René Seybold for Hohner in 1950. It is a monophonic electronic instrument with the design of an accordion, but is a bass synthesizer with vacuum tubes, technically comparable to Harald Bode's Multimonica.
The Electronium is equipped with a keyboard of 41 keys or buttons and with 16 stops. The volume is controlled with the bellows. The instrument has a separate amplifier and speakers.