Mod Duo Audio through USB on Ubuntu

Hi everyone, my time to ask for help!

I’m trying to use my Mod Duo as an audio interface to do some simple recording.

I’ve followed the instructions on https://wiki.moddevices.com/wiki/Audio_Through_USB and everything seems to be fine in the Mod side.

However, on my computer, when I start jackd, everything seems fine at first, but it is not working.

Trying to create new project in Ardour, connected to jack, it breaks and says it was not possible to create the project. If I try connecting to ALSA, it works.

If I try to use Audacity, changing the Host to Jack, it starts recording but there is no audio.

On the terminal where jackd was launched I see:

JackEngine::XRun: client = PortAudio was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = PortAudio was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = PortAudio was not finished, state = Triggered
JackAudioDriver::ProcessGraphAsyncMaster: Process error
JackEngine::XRun: client = PortAudio was not finished, state = Running
JackAudioDriver::ProcessGraphAsyncMaster: Process error
  • I’ve got a simple pedalboard just connecting inputs to outputs and a mic connected to y device
  • I’m not starting jack control (QJackClt)
  • I’ve installed jack without realtime, and also tried starting jackd without those options

I guess is something conflicting with Ubuntu’s default audio host, but I’m not sure how to solve it.

Thanks in advance!

Audacity is a little weird to use with Jack. As far as I know, the inputs and outputs only appear when the Audacity transport is active. I had to stop using it. I don’t have a Mod box at this moment so can’t delve any deeper.

Check the jackd connection between the duo and the host:
Ssh into the duo and run “jack_lsp”.
You should see some “mod-slave” lines in the output.

You can start qjacktcl after you have started jackd, just don’t use the start button (or auto start).
You should be able to see and make local connections (but not those to the duo).