Sunday, January 09, 2011

A-178 Theremin Control Voltage Source

The Theremin, invented in the late 1920's by Léon Theremin was one of the earliest electronic instruments.
The instrument is known for it's distinctive ( spooky ) sound, but most of all for it's playing method; Instead of playing it with a keyboard, the Theremin has antennas that sense the movement of the players hand, without touching the instrument.
Best known for playing the Theremin is Clara Rockmore, one of Theremins finest students.

Most theremins use two antennas, usually one for pitch and one for volume, so with two Doepfer A-178 Theremin Voltage Source modules, an oscillator (VCO) and an amplifier (VCA) module, it is quite easy to re-create the sound of a 'real' Theremin. You can even easily extend that sound by patching in filters or other modules.

And again, that is what makes the A-100 modular so versatile. 
Instead of just recreating the original Theremin you can use the module as a control voltage source for other modules. 

The voltages can be used for controlling any voltage controlled parameter of the A-100, e.g. pitch or pulsewidth (VCO A-110/111), loudness (VCA A-130/131/132), panning (A-134), filter frequency or resonance from all of the filter modules, phasing (A-125), frequency shift (A-126), resonance peaks (A-127), envelope parameters (A-141/142), and tempo (A-147), to name just a few ;-)

The Gate-output with adjustable threshold (not available on the original Theremin) is a nice extra output. I often use this for (re-) triggering notes or filter effects, but it can also be used for starting sequences (A-155) or for reset or switching functions (A-152).

Doepfer recommends if two or more A-178 are used the distance between the modules/antennas should be at least 30 cm to avoid interference.