Gamechanger Audio Motor Synth MkII

Gamechanger Audio’s Motor Synth MkII updates the company’s idiosyncratic approach to synthesis...

In 1681 Robert Hooke presented a device to the Royal Society that used a toothed wheel to produce tones of a known frequency. There have been plenty of devices since that have used rotating discs to produce audio, but the high speed, small size and precise control of Gamechanger Audio’s motors have led to a compact device that can easily fit on a desk. No need to split it in half like a Hammond B3, and notably more portable than Thaddeus Cahill’s 200‑ton Telharmonium.

Rather than serrated tonewheels, however, the Motor Synth primarily uses light to generate a selection of wave shapes. An infrared beam is shone onto a pattern printed on the underside of each rotating disc, and the reflection is read by a sensor. There is also an electromagnetic sensor placed near each motor for an additional wave shape.

Without going into an extended history of optical synthesis, it might be worth mentioning the Vako Orchestron (as used on Kraftwerk’s ‘Radio‑Activity’), Edwin Welte’s Light‑Tone organ, Daphne Oram’s Oramics system, and of course Yevgeny Murzin’s magnificent ANS machine. These all use a graphical element that creates audio by modulating light, a technology found in early naval communication and cinema film sound.

The optical discs rotated by the motors......are ‘read’ by sensors on the board beneath.On the underside of each disc there are three graphically printed waves: sine, square and saw (descending ramp). These are represented by a varying density of ink changing the amount of light reflected, rather than a geometrically drawn wave. The patterns on the top sides of the discs don’t generate any audio, but the strobed light within the casing creates pleasing visual feedback in the same manner as the dots on the edge of a turntable. The effect is particularly satisfying when a subtle pitch modulation causes the pattern to drift back and forth.

The Motor Synth MkII has eight brushless DC motors in total, with four assigned to each voice. As well as two motor voices with four‑note polyphony, there is a DCO (new for the MkII) that can be added to the mix. The DCO is configured mostly via the two encoders under the screen, and includes a noise source, hard sync to the motors, and some novel wavefolding capabilities.

Note that the VCAs and envelope generators are polyphonic, but the filter is paraphonic, ie. it re‑triggers for all notes played within each of the three voices. There is an analogue filter for each motor voice, and a digital filter for the DCO.

Features

Downstream from the signal path of these oscillators are the mixer, VCAs, multimode filters and drive effect. Parameters can be manipulated by a number of modulation sources, and there is a built‑in sequencer and arpeggiator. Note that if the knob doesn’t have an indicator stripe then it’s a push‑button encoder — operation becomes a lot easier as soon as you realise this!

Of particular interest is the ‘clutch’ feature. This is a wonderfully intuitive concept that’s great fun when performing. Hold the clutch button and make changes to the filter and modulation knobs, etc, and then release to drop in all the changes at once. This works well when jamming along with a drum machine.

A keypad comprised of eight push buttons allows notes to be played as soon as the synth is switched on. This is useful for previewing sounds, although you’ll presumably want to connect a more comprehensive MIDI controller as soon as you can. The keypad is a good addition to get started quickly, and to keep the unit self‑contained.

The keypad is also used for the built‑in step sequencer, with the illuminated buttons lighting up as you might expect. The sequencer definitely rewards exploration, with control of some interesting parameters including glide, ratcheting, probability and the ability to repeat steps. It doesn’t take much effort to add interesting variation to a looping sequence. There’s also a terrific multi‑channel ‘motion record’ feature that allows knob movement to be recorded, but also played back at different speeds and in different directions.

One slight restriction is that there is only one knob for all of the sections of each...