Getting USB audio interfaces to work on (Arch) Linux

I’ve been having problems with getting external USB audio interfaces to work on my computer. I have a guitar and wanted to plug it into various external interfaces, and it didn’t work properly.

In the end, the trick was to tell jack to use a different audio interface for input than the one for output.

This is how the config looks in cadence:

In the above, note that “Input device” is hw:1, whereas “Output device” is hw:0. For me, that’s the trick that worked in the end.

I found this via https://answers.bitwig.com/questions/1134/how-do-i-correctly-setup-audio-under-linux, which describes how to set up audio for Bitwig Studio, but really works for more software, I think.

In addition to this, set up realtime audio, by installing the realtime-privileges package and adding yourself to the realtime group. (Don’t forget to also set it in jack/qjackctl/cadence.

Hints:

• use aplay -l to figure out if your sound card is recognized correctly
• have a look at the “Input Devices” in pavucontrol, if your audio interface appears there and is shown receiving sound (via the level that is displayed there)
• look at dmesg -w for kernel/driver messages

(Note to self: The image above was taken using scrot -s, and then compressed using tinypng.com. convert image.png smaller.webp also worked, made the image go from ~21000 bytes to ~10500 bytes. But tinypng brought it down to ~8500 bytes.)