I had already been experimenting with alternative ways of getting subharmonics, for example the gated LFO feature that you mentioned. However it seems I was getting a lot of aliasing when bringing these into audio range. With the Harmonic oscillator clearly already running in audio range, I was thinking of avoiding that issue altogether. Best of all, easy access to multiple channels of undertones next to the 'master' would get us into Trautonium territory very quickly - and beyond (with the capability to use different waveforms).
The interesting thing about the subharmonic series is the musical options offered by the undertone series - quite different to the overtone series which are obtained through multiplication. Where overtones are on the major scale, undertones are actually closer to the minor scale, but not all align exactly to traditional chromatic notes.
In the past, subharmonics were used on the Trautonium electronic instrument (as performed by Oskar Sala - for example on his album Subharmonische Mixturen - his 'Mixtur Trautonium' apparently uses features such as formant filters, frequency shifters and delays... Mutable Rings 'Disastrous Peace' and Warps 'Parasites' to the rescue!
For example, the Doepfer A-113 (http://www.doepfer.de/a113.htm
) supposedly faithfully replicates the subharmonic generator of the Trautonium - offering 4 separate channels with division values of 1 to 24.
Interesting that you highlight the existing 1/2 and 1/4 dividers in Harmonic oscillator mode, since I did notice these as well. Still, the more interesting harmonic values lie beyond pure sub-octaves, for example the more interesting divisions 3, 5, 6 and 7. Please refer to https://en.wikipedia.org/wiki/Undertone_series
- probably more accurate than I can describe here.
In any case, casually looking at the source code lines you indicated... simply replacing the dividers would clearly be a blunt hack.
Although I'm not sure if that array ouroboros_ratios could simply be extended, but in that case going all the way from 1/8 (fully anticlockwise) to 1 (noon) to 8 (fully clockwise) would probably make most sense, at least to start off with... (probably 24 or 32 would be best, but that might easily become unpractical when laid out across a single knob...)