I don't think the macro knob functionality can be changed - it would break almost every patch.
However, you can achieve unipolar-like functionality. If you turn a macro knob fully ccw to -99, then you make the mod matrix assignment and set a mod amount and bias the parameter you're modulating so that it's at your zero position, then you have a unipolar macro knob.
E.g. from an init patch: enable both VCO 1 and 2, tune VCO 2 one octave up using the coarse tune, set M4 to -99, assign M4 to VCO 2 pitch, set the mod amount to, 31'ish and fine tune the mod amount to match the VCO 1 pitch by ear. Save the patch - the current macro knob values are saved, just like all other parameters.
Et voilą, you have a unipolar, upwards only macro control for VCO 2. It will go to 1 octaves up at macro position 0 and to 2 octaves up at macro position +99 with this specific bias and mod amount, And you can have both unipolar and bipolar macros in the same patch. If you tune VCO 2 6 semi tones sharp and use a mod amount of 22'ish, you get a range of 1 octave. To get a downwards pitch sweep instead, just change the signs on the bias and the macro knob (or the mod amount).
It requires the biasing of the parameter(s) and the fine tuning of the mod amount, but it does what you want without changing any functionality.
Now let's go one step further:
From an init patch: enable both VCO 1 and 2, set M4 to -99, assign M4 to VCO 2 pitch, set the mod amount to 31'ish and fine tune the mod amount to match the VCO 1 pitch by ear, set M3 to +99, assign M3 to VCO 2 pitch, set the mod amount to 31'ish and fine tune again to match the VCO 1 pitch.
You now have a patch where M4 tunes VCO 2 upwards up to 2 octaves in a unipolar fashion, M3 tunes it down up to 2 octaves in a unipolar fashion, and you can always land on zero with no problem. Again, using a mod amount of 22'ish, you get a range of 1 octave, both up and down.
P.S. To find the a specific
range is a bit of a black art ATM, at least for precise pitch control. I haven't found a method for determining the mod amount value for hitting precise intervals for the range of a macro knob yet. It's too late on a Saturday night to figure out why a mod amount of 22 gives 1 octave and 31 gives 2 octaves... Perhaps Arturia can give us the formula at work? It may not be so critical for other parameters than pitch control though.
P.P.S. I just found that for the one macro knob method of controlling pitch, a bias of one and a half octave and a mod value of 38'ish give you 4 octaves range (thus 38 should give +/- 4 octaves for the twin macro knob method). We have 3 datapoints now - I'm sure the logarithm at work for the mod amount can derived from these experiments, but not by me on this Saturday night after a few beers - again, I'd prefer if Arturia enlightened us
P.P.P.S. Anyway, the unipolar macro method by biasing is easy enough to understand without complicating it with the precise tuning values - I just used pitch for these examples because it's easy to hear both absolute and relative values...
