Recently I found a new way to configure my modular synthesizer to generate semi-random musical parts. Hear is an example…
The somewhat oriental flavour comes from constraining all notes to a major pentatonic scale: C, D, E, G, A. All the sounds were made using a replica of the famous 1970’s ‘Minimoog‘.
Only the main tune (heard at the beginning) was actually played by hand. All the other parts were generated automatically using variations on the system below.
Like all analogue synthesizers, it relies on the principle of “Voltage Control” proposed by Dr Robert Moog in his 1964 paper. For example, pitch is calibrated at 1 volt per octave.
- The Sequencer, a replica of the ARP 1027 module, is stepped slowly, say every 4 beats (whole note), to produce a different Control Voltage (CV) at each step.
- This CV is modified by a voltage processor (based on MATHS), to produce a smoothly varying CV, say in the range 3-5 volts (equivalent to 2 octaves).
- Next, a Quantizer is used to repeatedly sample the CV, say at each half beat (eighth note), picking the nearest note from the chosen scale, and holding for the duration of the note.
- Finally, this modified CV controls the pitch of the ‘Model D’ replica monophonic synthesizer. The sounds can be further triggered and timbre modulated independently.
All the timing is controlled by four Low Frequency Oscillators (LFO), synchronised in different ratios to drive the various components at different rates.