Inside Therevox Custom Musical Instruments

Reader Stephen Young created this short film, Therevox – Wood & Wires, which takes a look inside the workshop of Therevox Custom Musical Instruments.

Since 2004, Mike Beauchamp’s Therevox has made instruments in the tradition of Paul Tanner’s Electro-Theremin and the Ondes Martenot.

Their ET-4 line is controlled by moving a finger along a reference keyboard, shaped to provide tactile feedback. Dual pressure sensitive intensity keys control the amplitude of the ET-4’s two independent analog oscillators. The ET-4’s performance options are rounded out by a low-pass filter, white noise generator and internal spring reverb.

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Turn A Junk Keyboard Into Bass Pedals (Synth DIY Project)


Reader Ville Aho, aka Electronic Melodist, wanted a way to play bass synthesizer while playing electric guitar, so he came up with a DIY way to non-destructively mod an old keyboard into bass pedals.

“I was interested to try using bass pedals while playing my electric guitar,” explains Aho. “Many rock groups such as The Police and Rush have used bass pedals (in power trio context). They used the legendary Moog Taurus – the most famous foot-operated synthesizer. The Taurus 3 is a dream machine but it’s like 2000 dollars! And it has only one octave keyboard.”

Aho’s solution was to take an old keyboard and mod it, with giant plastic keys and some MDI translation, so it would work as bass pedals. Here’s a demo of his ‘one evening’ Easy MIDI Bass Pedal project in action: Continue reading

Therevox ET-4.3 Synthesizer Inspired By Ondes Martenot, Electro-Theremin

Here’s a quick demo of the Therevox ET-4.3 continuous pitch analog instrument.

This includes a 4-mode MIDI over USB output, controlling two instances of AMsynth, an assignable expression pedal/CV input and intensity key “hold” knobs. Continue reading

Therevox ET-4.1 Features Expressive Control + Analog Sound


The Therevox ET-4.1 is an analog continuous pitch instrument inspired by the interface of the rare Ondes Martenot.

Each oscillator has six different waveforms, including the classic sine wave of the Electro-Theremin and the Ondes Martenot’s unique octiviant and white noise settings. Each oscillator can be tuned separately, or synched to create intervals or interesting harmonics. Oscillator 2 can also be set to a consistent note or used as an LFO to modulate the filter. The internal low-pass filter with variable cutoff frequency is used to shape the sound and this can also be controlled with an external expression pedal or CV source.

Here’s a video intro to the Therevox ET-4.1: Continue reading