Thanks for coming back to me on this topic.
I have a MT-32 and a SC-55MK2 and SC-88Pro all connected in a chain and don't experience that.
Maybe there is something wrong with it? You did say it was cheap...
I've done some additional testing and I've ruled out the Roland UM-ONE and the SC88-Pro as part of the problem.
I have connected both to my modern PC and running the exact same games under ScummVM, they work like a charm with the Roland. Perfect music and no notes hanging.
I would suggest unplugging the UN-ONE and just using FluidSynth for testing purposes. If it still occurs (or not) then at least that helps narrow down the problem.
Fluidsynth sounds wrong and sometimes accelerates or slows down. No hanging notes though.
Also, not sure what is the default sound bank, but it sounds weird in some games.
Did you try switching around USB ports and is the HUB powered? For testing purposes maybe remove all unnecessary USB peripherals...
I'm using a MiSTer USB board (with one of those fancy cases).
I've removed all other USB devices (except the keyboard and mouse because I need them) and tried every USB port on the MiSTer.
The MIDI module is always detected, passes on the music notes, but the hanging problem remains
Also, keep in mind, a Roland SC-88 is not a MT-32 (or CM-32L) and they are NOT compatible regardless of the default soundbank. I'm not seeing where Ultima 6 even supports any Sound Canvas (or General MIDI) device at all.
Yes I know. That is why I have tried several games.
All the ones I tested work, but some of them sound wrong.
I was just providing examples of several games where I have the hanging note proble.
I am running out of ideas...