After a year of struggle, I finally got my setup working
>TL;DR: Getting the OXI One and QuNexus to work together ended up being one of the most bizarre MIDI debugging rabbit holes I have ever gone through. What looked at first like a simple compatibility problem slowly turned into a chain of hardware quirks, firmware edge cases, USB host weirdness, hidden controller mappings, and misleading diagnostics that took me way too long to untangle.
I had this perfect little setup with Korg Volca's, Roland Aira's and a QuNexus as a midi controller to play the notes. Everything worked and times were good. But then I bought the OXI One as a sequencer and that's where the problems began.
I tried connecting the QuNexus through its computer port (micro USB) to the Oxi One. Didn't work. Then I tried the midi out port, physically connecting the QuNexus to the OXI One already required extra hardware because the QuNexus uses that awkward Mini USB->Midi DIN 5 Pin -> TRS connection. However, the early firmware situation was rough. The OXI One would randomly spit out transport messages that triggered sequencers across my setup. Synths would suddenly start playing on their own for no obvious reason. That part thankfully got fixed in later firmware updates, but at the time it completely killed my motivation to keep troubleshooting.
I gave up on the QuNexus entirely and bought an Arturia Keystep instead. The Keystep worked immediately with the OXI One and basically confirmed the rest of my setup was technically fine. But after trying to force myself to like it for a long time, I just never connected with it. Kind of draining the fun out of making music and I stopped making music on my synthesizers altogether for a while, back to playing accordion.
Then about a year later I went on a family weekend and brought along the Micromonsta 2 with the QuNexus almost as an afterthought. Just a tiny synth and the weird little keyboard I had spent months fighting with. And somehow it was perfect. The setup felt immediate and inspiring again and I suddenly remembered why I had been so stubborn about making the QuNexus work in the first place.
That experience pushed me into trying the OXI setup again one more time. By then, OXI Instruments had released newer firmware updates which finally fixed the rogue transport message issue. I thought my problems were finally fixed. Instead, a completely different problem appeared. The QuNexus would reliably send Note Off messages, but Note On messages would only occasionally make it through. Most keys were effectively dead. Notes would either never trigger or get stuck in strange ways. Monitoring the midi stream on windows: "Everything is fine", but on the Oxi.. not so much.
At that point I abandoned the Mini USB->Midi->TRS path completely and moved over to USB. That opened an entirely different category of problems. This path seemed promising though. During my year of absence Oxi Instruments had released an update that should've fixed USB MIDI Controller issues. And initially it seemed to all work. The confusing thing was that the QuNexus looked perfectly healthy on a Windows PC, and the Oxi MIDI monitor showed proper Note On and Note Off events with valid channels. What made it worse is that it also showed on the Oxi Split (used to connect all synthesizers to the Oxi) was receiving Midi signals! This turned into a massive red herring because at first it looked like routing, channel assignment, Split configuration, or MIDI Thru settings. None of that was actually the issue. I spent hours inside the OXI menus chasing ghosts because the monitor showed activity, which makes you assume the data is already valid. After a lot of debugging I inspected the MIDI Monitor a bit better and it showed incoming note events while displaying zero values for velocity. The keyboard was clearly talking to the OXI, but the actual payload data was somehow getting mangled.
The zero-value note readings happened because the QuNexus's controller and keyboard layers weren't turned on in the editor. The OXI One simply couldn't read the raw pad data without those communication layers active. Once I turned both layers on and disabled the internal sequencer clock, the OXI One immediately started reading the correct note and velocity data. The reason my computers and other synthesizers didn't care about this is because they have much more forgiving USB drivers. A PC or a standard synth will automatically translate or ignore the QuNexus's raw, unmapped pad data until it sees a familiar note. The OXI One, apparently, uses a very strict, lightweight USB host driver. Without those communication layers explicitly activated, the note data sat in the wrong place in the USB packet, causing the OXI One to read the incoming fields as completely blank.
Then another issue surfaced immediately after. The lowest and highest keys on the QuNexus started generating overlapping notes while simultaneously flooding the MIDI stream/ The behavior was subtle enough that it initially looked like another OXI bug, but it turned out those edge keys still had hidden secondary modulation assignments attached to them. Clearing the pressure modulation mappings from those specific pads finally stopped the rogue CC spam and turned them back into normal musical keys.
At least now it all works. Perhaps there is someone who reads this in the future and comes across the same problems. Hopefully this helps. Time to make music.