If I set Middle Note to 3V, then the lowest 2 octaves of my sequencer (0-5V) don’t respond, and I only get a 3-octave range. I understand why, now, after studying this and playing around with it.
Setting the middle note to C5 / 60 and middle voltage to 3V will result in the µTune’s output reaching 0V when playing C2 (assuming 12notes/octave). Anything lower will be capped to 0V.
Took me a while to understand your setup completely and figure out the problem. I believe the core of the problem is this:
via CV you get inputs from 0-5V, which maps to note numbers 0..60
via midi you get inputs in a different range, but essentially you want to press the lowest keyboard key and get note number 0 and press the middle C and get note number 60. Correct?
Which are the note numbers you are receiving in µTune when pressing these keys?