Pimp My Mono

video upload by Cylob Sonic Research

"The Macbeth Micromac-D is a boutique analogue synth from 2013. It has a three oscillator design, and I think it sounds lovely. There’s just one problem. It can only play one measly note at a time! But what if it were possible to play this synth with unlimited polyphony, in real time? Let's find out!
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00:00 Introduction, Micromac sound demos
02:02 Technique explanation
03:51 First listen
06:27 Patch parameters
10:13 Multistage envelopes
14:03 Jam 1
18:49 Jam 2
19:52 Jam 3
23:26 Discrete MIDI notes
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Some additional information:

The explanation of the first patch was simplified. There are a couple of issues to contend with when generating polyphonic parts from a monosynth. There isn’t just one buffer in use, rather multiple in action. Every note on rotates the buffer to be recorded into. This allows the notes of the previous chord to die away while the next chord starts to play, if the playback speed for those previous notes still leaves some signal to be played.

Another issue has to do with recording. A new note on should kill recording into the previous buffer. Otherwise, the notes of the previous chord still in action will start playing a recording of the new note on. I made this selectable in the first patch, because the effect may be desirable from an aesthetic viewpoint.

One more consideration when using an analogue synth controlled with CV and gate as the sound source. If notes are already being held down when the source synth is retriggered, the gate will remain high. As a result, the envelope will not restart. Therefore it’s best to use an envelope generator which is able to be retriggered, like the Intellijel Dual ADSR. That way, every new incoming note will retrigger the envelope.

One last thing: neither version of the patch compensates for audio latency, which means that lower notes are a little late to start."