The Swarmatron is an analogue synthesizer or electronic musical instrument that uses a ribbon controller rather than a keyboard. It is noted for its use of multiple oscillators that are linked through a 'swarm' control, giving its distinctive sound and method of playing.
The Swarmatron is a fingerboard synthesizer like the Trautonium or Tannerin. A finger is placed or slid from side to side along a ribbon controller, controlling the pitch. Glissandi are obviously easily achieved, or careful finger placement may be used to play discrete notes.
The distinctive feature of the Swarmatron is its use of eight individual oscillators, under a single control. These oscillators produce an equidistant chord, where their spacing is under the player's immediate control. There are two ribbon controllers: the larger controls the pitch in the obvious manner, the second is used to control the spacing of the oscillators when in 'Swarm' mode. A large central knob on a rotary control may also be used to control this swarm.
The oscillators may also be switched on and off individually by a row of switches. With all but one switched off, the instrument becomes a simple ribbon-controlled monophonic synth, capable of the usual glissandi. Using combinations, and adjustment of the range control, allows a non-equidistant swarmed chord to be produced. The oscillators may also be preset to the usual chord intervals of major thirds etc.
The pitch control also controls a low-pass filter. This may either track the main pitch, or may be controlled by the second ribbon. With the sawtooth wave of the oscillators, this tracking filter controls the sound of the instrument.