Noise mode 3 (Top Cymbal) sounds different than real hardware

[Kagamiin]

Description

For some reason, noise mode 3 does something strange on ESFM. We assumed during initial investigation that all that the noise modes did was to toggle the rhythm mode phase calculation overrides for operator 4.

That turned out to be perfectly true for noise modes 1 (Snare) and 2 (Hi-Hat). But something else is going on for noise mode 3, specifically when operator 4 is modulated by operator 3. This makes ESFMu's output sound different than real hardware in this case.

What we've tried

We've tried to investigate some of the behavior through empirical testing, but we haven't been able to get very close.

It seems like when noise mode 3 is used, the pitch of operator 3 is doubled, but only for the modulation input of operator 4 - the output of operator 3 maintains the same pitch if that's enabled.

Test scenarios

TODO: publish test scenarios here