USB Midi in to USB Midi out

i have some problems with the Midi routing of the Zynthian.
My system consists of a headless Rpi4 with a Hifiberry DAC ADC+ card in it. Connected to USB is a Arturia Minilab Keyboard and a Blokas Midihub via USB.
System works like a charme and i really enjoy the Zynthian Spirit.
One problem that i have is, that i cannot get the input of the keyboard to be send out via the midihub. I know, thta it is possible to do this with the Zynthian and have done this before with a different setup. So maybe its the midihub, or i am too stupid to find the right settings (for there are quite a lot). Maybe someone can help me with this problem. I put some pictures i made in the rehearsal room below, maybe this helps.

Thanks a lot for all the great work with the zynthian, really a great project.


Could you post a detailed scheme of your setup, including MIDI connections? Some good photos could help too.


Hi @rockinlord,
how you have routed midihub? You need virtualy connect usb port with DIN midi ports…

some scheme or photos could help…


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I will make some better pictures the next time i am in the reherseal room.
it is really just a usb keyboard and the midihub connected via usb.

i have programmed the midihub right. it is sending all usb midi input to the DIN midi ports, when it is connected to a computer.
it must be a problem of zynthian routing. if i look in the zynthian midi log i can see the midi input from the arturia keyboard, but it is not sending the informations out to the midihub. If i send something to midihub DIN input the zynthian is getting the informations right. Just the output from zynthianis not working.

also i dont really understand the differnce between the midi out and the midi feedback ports of the zynthian.
thanks for helping.

Hi @rockinlord ,
I tried configuration with Blokas MidiHub and Zynthian at home.

In my case:

  • Input source AKAI EWI USB conected to USB port on Zynthian.
  • Blokas MIDIHUB conected also on USB port of Zynthian, wiring USB A in to DIN A by MidiHub Editor.
  • From MidiHub DIN cable put on Din In Midi of Anyma Phi

I used Zynthian software from “staging-2109” source, I had not time to switch to “stable”.
All was working, the Anyma Phi played, for me.
Here are the important screens:

I see different connection of MidiHub. In my case i have short names. In your case the midihub is connected by a2j… so is question WHY? Im not specialist in this area…

There was a change to Zythian a few months ago to avoid a2j grabbing physical MIDI ports. This resolved an issue with port with spaces in their name not working. Maybe the fix is not yet deployed to stable. Don’t worry, an update to stable is due within the next few days :grinning_face_with_smiling_eyes:.

Ok, i will wait for the next stable update and switch to that.
Thanks for the help.

Swapped to the new stable release yesterday and it works like a charme.
Again, thanks for the support.