Math/logic error in mod matrix depth?

If I assign one of the assignable encoders to CC119
In effects create an lfo
In effects matrix, assign cc119 to lfo depth with offset 0, bipolar mode, depth 100%

At first I tried mapping out the errors in the value to see if there was a pattern, but over time it just got weirder and weirder.
Currently cc119 is at 84, LFO depth is -68%

If I change CC119 to … 97…I get… LFO depth -47%
CC119=26… lfo depth -100%?

I’m only using the internal assignable encoders, no other CCs incoming from other devices.

The issue is the modulation mode should probably be set to unipolar, not bipolar.
The visualisation of the modulation can be really helpful to figure out the way it all works.

Currently cc119 is at 84, LFO depth is -68%

Let’s reason in terms of the range of values of both the source, and the destination:
84 is ~66% of 127.

Bipolar mode & offset 0% means the entire lower half of the source signal is clipped to 0. Because of the clipping of the lower half of the source range, that means 84 is mapped to 66-50=16% of the destination range.

The destination range is -100%…100%, so 16% of the way there is roughly 16% of 200 above the minimum value, so -100 + 32 = -68

Thanks for the detailed explanation! I don’t think I’m understanding the modulation conversion very well between bipolar % and CC… It makes my head hurt haha. Is there a simple equation or something to visualise this? Even with your explanation above I am having trouble imagining it.

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