I’m pretty sure you already get this part but, for others following along, there is only one FIlter, one Amp, one Filter EG, and one Amp EG that are all shared by both notes (as well as SUB OSC, NOISE, and EXT IN).
The owner’s manual describes MULTI TRIG this way:
“By default, playing legato on the Sub 37 prevents envelopes from retriggering on subsequent notes; this is called single triggering. You can change this behavior by pressing the MULTI TRIG button. When illuminated, a new gate occurs each time you play a note on the keyboard, regardless of whether you’ve released the previous key; this is called multiple triggering.”
So… the defined behavior of MULTI TRIG is that, if you’re holding more than one key, and then release a key while still holding a key, the envelope is going to retrigger because the remaining key is now treated like a new note on.
What it would require for your desired behavior would be some special-case mode that, only when DUO MODE was lit, acts like MULTI TRIGGER whenever you play a key while a previous key is already held, but… doesn’t retrigger whenever a key is released while another key is still being held.
I have no idea if such a special-case DUO MODE MULTI TRIG behavior could/would be created. But, at least it’s now in print as a request.
This is also really annoying me. Just got my Sub 37 and love it but the Duo mode is really restricted by this.
There should be a way of retriggering the envelopes only with a note on (i.e. not with note offs). This way, for example, a low note could be used as a drone with a melody played higher up the keyboard. Playing the higher key would retrigger the envelopes, but the note off would not affect the position of the envelope. As it is, if there is a filer env on the patch the low note filt env retriggers when the higher key is released which can make things sound cluttered. It would be good if the second oscillator (which will now be playing the low note as well as the first) could start in the middle of the envelope so as not to start the envelope attack i.e. fall into the existing envelope position
I’ve the Gmedia oddity, which doesn’t retrigger on note off when in duo mode - but no idea if a real arp would act similarly.
I think the architecture should be able to cope with this, as it doesn’t require 2 separate tilt envs, rather a different triggering routine.