On a product with an interface (such as the Pro-2 or Prophet-12) which possesses an OLED screen + four encoders underneath, it wouldn't be impossible to set the voice allocation, i.e., 4-3-4-5 amongst four parts / sixteen voices. Each value would adjust left-to-right as you change from, say, 4-3-4-5 to 5-2-4-5 (or whatever).
The issue, as I see it, is that you'd really need a 61-key, four-zone controller paradigm within which to understand how the unit should behave; for live performance, it's really not very practical (two hands and all*) unless you're layering A+B | C+D zones with a split in the middle (which is really close to a Prophet-12 keyboard + module anyway).
You'd quickly start running out of usable space on anything less than five octaves, and would likely need some sort of sequencer across more than one zone, which takes you back to the Tempest as a nominally better solution (if your use of multitimbrality is confined to single note effects or very limited ranges).
* - and yes, Tim, pedalboards
Well that would depend again on how you are using it. If you are having a bass patch run an arpeggiator on latch, a string/brass layer can be played with one hand while a lead patch can be played on the upper. Or you can layer four patches at once, or have two layers on each side of a single split or have sequencers control two or three patches while you play the remaining on the keyboard.
It all depends on how you approach it. I think a lot of people automatically assume that I’m implying it be used for a four layer detuned mono synth...I mean you can but I’m more approaching it from a live or “off the floor” composition tool.
My reasoning for this is to have an instrument that you can record multiple parts to a song live as oppose to recording one patch, going back recording another. The Rev 2 is great but there’s no way to switch between patches quickly or accurately enough in an “off the floor” session. I understand random patch access wasn’t included to keep cost down but even just two increase/decrease buttons would help as it’s too easy to zoom past a desired patch with simply a dial.
As far as the size...I’m picturing two rows of a Prophet 6 module with the buttons
Split
Stack
Multi
In a column down the centre.
Also each module would have the button (Keyboard Off) which essentially disengages that module from the keybed allowing it to be played by the sequencer alone.
As far as polyphony goes, much like when in Unison mode on the Prophet 6 you can determine how many voices it’s using, you can also do that with each module.
There you go. Everything is on the front panel, you have knob per function with no extensive menu diving (if at all).
Robot Heart next time you are at the office maybe put together four Prophet 6 modules (two side by side and two side by side above those) and see the size of the thing and if you have a 5 octave keyboard see how it might look. it actually might not be that bad logistically.