DFAM: Three Voice Paraphony (no external patching)

Published on Apr 26, 2019 Kris Lennox

"Three independent voices on the DFAM. No external patching. The initial challenge is to have two voices of independent pitch: if velocity is patched to VCO 1 CV (or VCO 2; in this example I've patched it to VCO 2), the velocity potentiometers now control the pitch (plus velocity).

VCO 1 steps were individually tuned, then VCO 2 steps were tuned to harmonise VCO 1. The independence of the voices can clearly be heard i.e VCO 2 isn't just a transposed form of VCO 1 (you'll hear various intervals, contrary motion etc), but a fully independent line.

The next challenge (and least obvious) is to create a third voice. Given the DFAM is a two-osc synth, having a third voice initially seems unlikely/impossible. But the solution is:

If self-oscillation is possible on a VCO, it is also possible without the VCO. It is more a case of: If self-oscillation is possible on a synth, the control parameter(s) determining self-oscillation can be reassigned to another parameter/act as a false carrier of the original self-oscillation patch/algorithm, i.e what is required is something else acting as carrier of/for the self-oscillation.

Patching the VCA to the External Audio line allows for this extra self-oscillation. Note that cutoff/resonance/volume all affect self-oscillation in this state, therefore adjusting these parameters will affect the pitch of the self-oscillation (as can be seen when I'm adjusting the cutoff in the second half of the video).

Granted - not a full line of paraphony - but it can certainly be considered an independent voice (i.e it is unaffected by the pitches of VCO's 1 and 2), plus the resultant three-note harmony when combined with the other two lines.

Very useful (the principle can be applied to any synth with a similar architecture).

Quite a lot of work when the parameters herein can be controlled with external modules, but adding external control removes the challenge of finding solutions within the architectural constraints of the synth (or rather, 'a' synth) as a standalone unit.

Many other possibilities with the DFAM beyond the documented scope. As with most every synth i.e ratcheting on various devices considered 'un-ratchet-able' etc.

PS reverb & delay added to the patch.

All best
Kris"