I’d been experimenting with plucky sounds and was using the Env 1 to Env-1D method to shape the curve. It was working great in binaural mode but when I switched to 12-voices the modulation stopped working on some voices and was okay on others.
I then tried using Env 1 modulation on some other destinations and they were equally unreliable in 12-voice mode. I think it is actually alternating voices where it is working and not.
This suggests to me that it might be a bug in using the correct Env 1 envelope for modulation for either the odd or even numbered voices in 12-voice mode. I’m guessing that in Binaural mode it uses just the one envelope for both paired voices, which is why it works fine.
ENV-1 is summed via an analog VCA into the filter to provide full precision even in the most subtle envelope - there are only 6 analog VCAs so for non standard routings you may run into this limitation. Similarly the A D S R controls are only 6 part multitimbral, meaning that they can have different values for 6 binaural voices, but not for 12 voices. For your curve shaping application, I think you’re limited to 6 voices due to the latter architecture.
There are 36 unique envelope generators not including the lfo amount envelopes, but the Adsr time controls for each of the two main envelopes are shared between left and right, even though the gate and scale/amount is unique for all 12.
Monotimbral analog polysynths typically share the adsr time controls between all voices, so the super 6 greatly improves on this allowing 6 completely unique timbres (ie all/any controls different) but does not allow for a different envelope shape completely on all 12 voices.
Gemini does not have the same limitation, and the attack parameter could in theory be modulated to be different for all 20 voices for example.
Analog VCAs are in abundance on the voices of super 6, and as well as 12 final VCAs there are 12 envelope level VCAs each for ENV1 and ENV2 allowing true 12 voice note articulation, but poly modulation for a limited subset of parameters is limited 6 voices (binaural mode).
As well as analog final VCAs, Analog VCAs are used to scale the envelopes for full numerical precision of the smallest envelope modulation amount, this subtle touch makes the responses more natural but of course analog hardware duplicated per voice is a luxury.
