Hi All,

When attempting to control a guitar pedal with MIDI from my 2018 Mac Mini (10.14.6), Voodoo afflicts MIDI control change messages sent from my UCX when it's connected by USB but it works properly when connected via Firewire.

Mac Mini —> USB —> RME Fireface UCX —> Chase Bliss MIDI box —> Thermae.

Sweeping (for example) CC15 (controls LPF) from 0 to 127:
    a. starts correctly at 0 (Filter Closed)
    b. consistently there is a response "like 0" (i.e. Filter Closed) at values of 16, 32, 64, (not 48), and 80. i.e. at 31 there is sound, then 32 closes the filter completely etc. (There could possibly be other “0” points but not as obviously.)
    c. At max 127, the response is noticeably less than the equivalent max knob position.

I have ensured using latest RME firmware and USB drivers etc. - no difference.
I have also confirmed that the behaviour with my newly arrived MOOD is the same 16, 32, 64, 80 nonsense, so it is not in this regard unique to my specific Thermae unit, which is (sort of) good.

Mac Mini —> An orgy of overpriced Apple Thunderbolt converter dongles —> Firewire —> RME Fireface UCX —> Chase Bliss MIDI box —> Thermae.

1. Sweeping CC15 (LPF) from 0 to 127 worked like a charm! No null points at 16, 32, 64, 80.
2. All other CCs seem to work.

Conclusion/Suspicion: Since UCX on Firewire talks successfully with Thermae, extremely unlikely to be purely Thermae related. Perhaps something between UCX and the class compliant MIDI drivers used under USB, maybe a 32bit / 64bit compatibility problem...
When using UCX over USB, maybe there is some sort of low level disagreement between the UCX and Thermae causing it to drop or misread data bits in MIDI control change event messages. Possibly the computer or interface is able to send / parse some MIDI bitstreams that Thermae cannot?

Anyone have any thoughts?