Key Appropriate Pitch Spreader

There's a particularly interesting group of instruments called Modular Synthesisers that lies directly within the intersection between electronics, signal processing, music and crazy. Some folks create self-evolving musical compositions that require nobody to play by wiring up complex racks of blinking hardware, others craft interestingly modulated space-noises or clinically obese beats, the likes of which are normally found only within the minds of deeply disturbed psychedelic warlords, long since disappeared into smoke.

Basically, various bits, or modules, are patched together with wires, so perhaps an oscillator is wired so that the flat amplitude of a basic waveform is modulated into an envelope, filtered to round out the sound, and triggered on receipt of a pulse from an expensive bit of kit called a sequencer.

A sequencer is a thing that triggers pulses in sequence, each of which can be used to play a note. A note who's pitch is controlled by a twiddly knob. Put a bunch of notes in sequence, and there you go, you're Mozart, tunes and stardom await.

A cheaper version of a sequencer can be created using a thing called a Clock Divider - basically, you send in a clock signal, a series of ticks, and the divider will send out a pulse on say every 1, 2, 4, 8 and 16 steps each pulse generated on a different output. Plug in voices on say 1 and 4 - and you've got the basis of a simple 4:4 rhythm. Normally each voice has its pitch set - but comes at a price - and you don't want to have to set up multiple voices just to supply different pitches - some tunes can have up to 16 individual notes (ask Mozart) which in module terms would very rapidly break the bank.

So here is an idea for a modular synth module, designed to generate a song's worth of pitches (or at least pitch-control voltages) that could be patched into a single voice and triggered by a simple Clock Divider to create simple but cheap beats.

The module consists of the following inputs: CV In, and outputs 0, 1, 2, 3, 4, 5, 6, 7. Additional controls include: A fine-tune pot, a {flat, regular, sharp} 3-position switch, and a {regular, 5th, 7th} 3-position switch. Optional extras for the delux version might include individual off-key modifier switches {flat, reg, sharp} for each output - but let's concentrate on the basic version for now.

So a control voltage goes in, and populates the outputs with chromatically pleasant output voltages according to the scale switches which define the musical key being generated. Each output 0 through 7 (or whatever number is deemed appropriate) can then be used as the pitch-control for a subsequent envelope/modulation thing.

Another way to think of it might be as a temporally parallel arpeggiator.