USB MIDI host mode?

[SynthGal]

I am currently running MiniDexed on an RPi Zero 2W. I would like to connect both my Korg Nanokeys (eventually I want to instead use my Nanocontrol, but I'm using the Nanokeys for simpler testing) and my Yamaha QY70 (via a Turtle Beach USB MIDI interface). I would like to be able to send MIDI messages from the Nanokeys to the QY70. From what I can gather from https://github.com/probonopd/MiniDexed/wiki/MIDI-Thru this is possible, but after trying several different combinations of from/to I can't get it to work.

Is this possible or am I misunderstanding the documentation?

[probonopd]

Hello @SynthGal, welcome to MiniDexed. I don't own your hardware, so the following is my educated guess, as I had no chance to actually test it.

To connect your Korg Nanokeys, Yamaha QY70, and MiniDexed (running on a Raspberry Pi Zero 2W with the MiniDexed firmware), you have two supported options:

Option 1: USB + Serial

• Connect the Korg Nanokeys via USB — MiniDexed acts as a USB host and will recognize it as umidi1.
• Wire the Yamaha QY70 to the Pi’s GPIO UART pins for Serial MIDI (MiniDexed sees this as ttyS1; use proper circuitry - i realize that we are only describing the input so far but also need to describe the output I guess).
• In minidexed.ini, add:
  MIDIThru=umidi1,ttyS1

This routes MIDI input from the Nanokeys to the QY70 over the Serial MIDI port.

Option 2: USB Hub + Turtle Beach USB MIDI Interface

• Connect a powered USB hub to the Pi Zero.
• Plug in the Korg Nanokeys and the Turtle Beach USB MIDI Interface — MiniDexed will enumerate them as umidi1, umidi2, etc.
• In minidexed.ini, add:
  MIDIThru=umidi1,umidi2

This routes MIDI from the Nanokeys (e.g., umidi1) to the Turtle Beach interface connected to the QY70 (umidi2).

Important: This setup assumes your USB MIDI devices (including the Turtle Beach interface) are USB class-compliant. That means they do not require special drivers and conform to the USB MIDI device specification.

How to tell if it's class compliant:

• If the device works with generic MIDI drivers on Windows, macOS, or Linux without needing extra drivers, it's class compliant.
• The Korg Nanokeys and most basic MIDI interfaces (like Turtle Beach or Roland UM-One) typically are.
• Proprietary devices from some manufacturers may not be — check the documentation or test it with a standard OS.

You can include multiple MIDIThru lines in the config for more complex routing if needed.

[SynthGal]

So it turns out that my Turtle Beach interface is dead. Like, does not show up in lsusb or dmesg at all, tested on two separate computers. That explains why I was having so much trouble getting it to work. Sorry to waste your time.