Maybe install something like this:

$ sudo apt-get install pavucontrol

It should show you the audio routing. Some users have reported audio switching to HDMI output or something else unexpected - and this program should allow for you to diagnose that sort of thing.

I'm guessing you should get the same kind of information from "alsamixer" - not sure why I've seen a suggestion of the above utility.

You could try reinstalling audio.

sudo apt-get remove --purge alsa-base

	sudo apt-get remove --purge pulseaudio

	sudo apt-get install alsa-base

	sudo apt-get install pulseaudio

	sudo alsa force-reload

... or just "sudo alsa force-reload" by itself to see if that restores function (although probably temporarily).

I don't use linux with my audio setup - so I haven't had first-hand experience of this issue.

Thank you very much for the reply! I have tried the steps you indicated but, unfortunately, they did not work. To be more specific about the issue, sound output works from the computer to the keyboard via its usb interface for approx. 75 seconds. At that point, there is a small "pop" sound and sounds no longer play through the keyboard unless the usb is unplugged/re-plugged or the computer is restarted. I have used a completely different usb audio interface that works fine without issue.

I have tested this issue quite a bit over the last few days by using the aplay command to play a wav file and to direct output to a specific interface (aplay -Dsysdefault:CP88CP73 -vv file.wav). I have tried other players and audio files too with the same result. When the issue happens I notice that after the sound stops, the audio player app still shows that it is still playing the audio. Regardless of whether I use jack, pulseaudio, or even alsa directly without audio server on top, I still run into the same issue. I have experienced the issue in Ubuntu 18.04, Linux Mint 19, and Ubuntu 20.04. I started thinking that it may be a usb suspend setting (more recent kernels enable this by default). However, disabling this for the keyboard (using these instructions - https://hamwaves.com/usb.autosuspend/en/index.html) did not help. I am out of troubleshooting ideas at the moment but, if anyone can think of anything, please do let me know.

There's also this:

sed -i 's/GRUB_CMDLINE_LINUX_DEFAULT="/&usbcore.autosuspend=-1 /' /etc/default/grub

	

	update-grub

	

	systemctl reboot

Thank you very much for the reply! I have tried the steps you indicated but, unfortunately, they did not work. To be more specific about the issue, sound output works from the computer to the keyboard via its usb interface for approx. 75 seconds. At that point, there is a small "pop" sound and sounds no longer play through the keyboard unless the usb is unplugged/re-plugged or the computer is restarted. I have used a completely different usb audio interface that works fine without issue.

I've been plagued by this same behavior too. But I've found a "workaround". Usually I'm working with Ardour over Jack and suddenly I hear a "pop" and sound stops. So I close Ardour, open a web browser, go to YouTube and start any video. After that, sound is restored and I can open Ardour again and continue working. Terrible workaround, but it's better than to reboot. I'll try to report this somewhere (probably the kernel bug tracker). When I do that, I'll post here so we can track it better.

Also, not sure if you'd fare any better starting with a distro that was built with audio in mind. Something like AVLinux or similar (there are several Audio/Video focused distributions out there). The thought would be that users of these distros are more concerned with having functional audio interfaces without pops and artifacts and that the maintainer(s) would be working to address these as a higher priority vs. the more generic flavors of Linux.

Not that you couldn't "roll your own" from the more generic starting point. However, it may be easier to start with a more dedicated build with most of this sorted out first.

Also, not sure if you'd fare any better starting with a distro that was built with audio in mind. Something like AVLinux or similar (there are several Audio/Video focused distributions out there).

Yes, I've tested it with Ubuntu Studio, 20.04 edition.

Any updates on howto resolve this by any chance? I recently ran into the exact same issue and tried similar fixes, none worked. Similarly to Joshua I tested multiple Ubuntu 18.04/20.04 based distros, tried to use jack or alsa, and disabled usb autosuspend:(.

I've been using it successfully with Pipewire instead of Pulseaudio and Jack. For Ubuntu users, I don't know if there's an easy way to install an updated enough version of Pipewire, but I would recommend trying it.