I have a multichannel audio interface connected to my MacBook Pro by USB. I set the interface as the output device in System Preferences > Audio, and the system audio is routed to outputs 1-2. I want to route the system audio to channels 11-12, how can I do this?

In Audio MIDI Setup there is an option to use the device for Sound Output, but there is no way to specify which channels on the device to use.

I am using a 2013 13-inch MacBook Pro running macOS Catalina 10.15.7. The interface is a Soundcraft Signature 12 MTK.

  • Mac model? Version of macOS? Model of audio interface? Have you looked at Audio MIDI setup?
    – Allan
    Commented Nov 18, 2020 at 0:46
  • Yes, I looked in Audio MIDI setup. There is an option to use the device for Sound Output, but there is no way to specify which channels on the device to use. I would like a solution that works for any audio device, or Mac running a recent version of macOS, that's why I chose to leave those details out. But just in case it helps to find an answer, I added them to the post.
    – audiomason
    Commented Nov 18, 2020 at 16:28
  • That ability must be provided by the driver. It's how the hardware (via the driver) presents inputs/outputs to macOS that enables you to do these things. If the driver only "gives" (lack of a better word) channels 1 & 2 for USB output, then that's what macOS sees. If you want something different, then you have to route it manually on the console (from the cursory read of the user guide found online). To confirm, your best bet would be to contact the manufacturer as they would know best how to configure the device to do what you're asking.
    – Allan
    Commented Nov 18, 2020 at 16:37
  • The interface is a class compliant USB audio device. It uses the USB audio class driver provided by macOS. The hardware presents 12 outputs to macOS, and macOS "decides" to use outputs 1-2 for system sound output. The other outputs are available to applications like Ableton Live. To be clear, this isn't a problem with the hardware. It's a problem with macOS not exposing any settings in System Preferences or Audio MIDI Setup that allow me choose which channels of an audio device to use for the system sound output.
    – audiomason
    Commented Nov 18, 2020 at 18:28
  • I was on their website and they have a manufacturer supplied driver for that model you specified. That said, the USB audio class driver is generic, it's not going to support every mixing console on the market. It's probably supporting the "base config" with this generic driver (I don't have one to test). However, I can tell you that to get my PreSonus outputs to work properly, I had use their driver. I imagine that it's the same case here.
    – Allan
    Commented Nov 18, 2020 at 18:49

1 Answer 1


After selecting the device for sound output in System Preferences, you must configure the speaker settings for the device in Audio MIDI Setup:

  1. Open Audio MIDI Setup
  2. Right click on the audio device and select Configure Speakers...
  3. Choose the configuration (e.g. stereo)
  4. Choose the channel destination for each speaker (e.g. left, right)

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .