So i tried to setup my keyboard to my computer and some weird things happen. The first thing i did was testing it with midi-ox. Everything seemed to work until i started playing chords or just 2 notes at once. It seems like it only can register one note off at a time, but the weird thing is that it sends 1 note off and the rest note on when i release multiple notes at once, so it does register something. But if i remove one finger at a time works fine as you can see on the second image. I really don't know what to do, could it be the interface? It was a cheap one from china.

single notes and multiple notes multiple notes releases one after one

  • Something cheap could indeed be buggy; one workaround would be to maintain state on what notes are on and ignore new note on events? MIDI otherwise lacks a message for "turn off multiple notes" so there will be individual messages over time for each note off event.
    – thrig
    Jul 22, 2016 at 19:47
  • Can you recommend some converters which isn't "buggy" and not too expensive. I don't have the biggest budget.
    – polo
    Jul 22, 2016 at 19:52
  • 2
    There is a good reason why "note off" messages are sometimes sent as "note on with velocity zero" messages. It reduces the amount of data transmitted over the MIDI link. Google for "MIDI running status" if you want to know the details. But I don't know what you mean by a "MIDI converter". It might help to edit your question to say what you are actually trying to do, and why it doesn't work. MIDI-OX might be irrelevant to solving the real problem.
    – user19146
    Jul 22, 2016 at 20:25

1 Answer 1


Your USB/MIDI interface is this model:
no-name MIDI interface with CH345
which does not work: not only does it garble any messages using running status, but it also corrupts SysEx messages.

Buy any other USB/MIDI adapter.

  • 1
    It's actually exactly that one i have. So you think any other interface could do it? Also i cracked it open... It's missing some important components... I think i will try to solder the missing components and see if it will work. If it doesn't can you recommend any good and cheap usb/midi interfaces?
    – polo
    Jul 22, 2016 at 20:52
  • The problem is not the missing optocoupler circuit (and you'd also have to remove R11), which would just remove the risk of a ground loop. The biggest problem is the buggy firmware in the CH345 chip, which cannot be changed. Any other USB/MIDI interface will work.
    – CL.
    Jul 22, 2016 at 21:29
  • I am seeing a slightly different thing where I am not getting any note off with this model of midi usb cable. I guess I should try another one, will try to remember to post back if that fixes it....
    – Colin D
    Mar 16, 2019 at 23:08
  • @ColinD This interface calls itself "USB2.0-MIDI", is that what you see?
    – CL.
    Mar 17, 2019 at 6:49
  • It calls itself something different, it is this model amazon.com/gp/product/B0017H4EBG/… on aplaymidi -i I get VIEWCON.. MIDI 1...it is an old synth dx21 but I have used something like this before...hmmm sorry lot of weird detail to add to the comment thread
    – Colin D
    Mar 30, 2019 at 22:24

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