Is it possible to integrate MOD Desktop with other audio sources/devices on the system?

Using MOD devices Usage Questions
#1

I am using MOD Desktop for past few days and it’s been great so far, however, yesterday I wanted to practice my setlist with my MOD pedalboard, and I noticed I can’t find a way to use it along any other programs on my machine (for example: playing backing tracks from MPV, or browser and playing along on a guitar).

When I start MOD Desktop, it seems to completely “consume” whatever audio device I assign it to.
When I use my USB audio interface to plug in my guitar, after starting MOD, it(the interface) just disappears from jack/qpw graph.
My system runs Pipewire. I can still play audio back through my system(laptop) speakers instead of audio interface output, but I can’t find a way to output all of the sounds through one device.

Something makes me feel like it’s just the way MOD is designed and it’s okay, but maybe there is a way around it. Are there any plans on changing that?

BTW. I thought maybe selecting “separate input” and using my interface as an input and my system as output would work as a temporary fix but my audio was completely messed up when I tried it. However, even if it did work, I don’t think I could also play other sounds.

Thanks in advance.

#2

You are already using pipewire, so you just have to pick “JACK / PipeWire” as the audio interface and everything you need will be possible. In this mode mod-desktop is just another client on the pipewire audio graph that you can connect to anything.

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#3

Thanks!

That’s awesome news. However there must be something wrong with my setup, because there’s no such option on the dropdown for me.

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#4

maybe you dont have pipewire-jack related packages installed?

please run the mod-desktop program from a terminal/shell, it should have debug output like this:

MOD Desktop DEBUG: jacklib syms 0x77ffe8e40ec0 0x77ffe8e453c0 | 257 | using pipewire with filename '/usr/lib/x86_64-linux-gnu/pipewire-0.3/jack/libjack.so.0'
--------------------------------------------------------
/usr/lib/x86_64-linux-gnu/pipewire-0.3/jack/libjack.so.0 loaded successfully!
--------------------------------------------------------
#5

That explains a lot. I get:

MOD Desktop DEBUG: jacklib syms 0x7f5b2afac0f0 (nil) | 65 | using regular jack
--------------------------------------------------------
libjack.so.0 loaded successfully!
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
--------------------------------------------------------

#6

ok then you either dont have pipewire-jack stuff installed, or it is not setup for use.

do any other JACK tools work? are you able to run jack_lsp and have it return a list of ports from pipewire?
that part needs to work before mod-desktop can work too

#7

Honestly, I have no idea.

I use default NixOS config which goes:

  services.pipewire = {
    enable = true;
    alsa.enable = true;
    alsa.support32Bit = true;
    pulse.enable = true;
    jack.enable = true;
  };

I don’t know what it does under the hood. I don’t have a jack_lsp available in my PATH.
I also can’t find pipewire-jack package or setting that would enable it on NixOS.

I definitely do have JACK. It autostarts with my system, Ardour is working fine, and for the first time I haven’t got any issue with audio on Linux. But I don’t know how to move from here. QJackCtl shows me that it’s running and everything looks good, but I don’t seem to have any JACK related tools in my terminal.

Of course, I could probably set it up on a regular Linux distro and NixOS makes everything a bit more complicated, but I’d like to sort it out. I’m just learning nixos, so I’m a noob, but I’m not planning to change soon. Btw. I’d love to package up MOD for nixpkgs one day. Just have to figure everything out and make it work. Once I’ll have a working declarative config that I can drop onto a new machine and start playing music, I’ll definitely share it.

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