R4.2 new install, no sys-audio, sound issues

I have a clean install of R4.2 on a machine that had no sound issues using R3.x or R4.0. Most forum posts dealing with sound issues seem to come from update-installs. This was a new install where I chose Fedora templates as the default. There is no sys-audio setup.

I have a combination of new AppVMs based on Fedora 38 XFCE, Debian 12 XFCE, Whonix 17, and some restored Debian 11 and 12 templates from earlier Qubes installs.

Switching the Dom0 Volume Control’s Configuration of the Built-in-audio, I am able to get the speakers to produce some sound, but it is crackly and very faint.

If I plug in headphones to the audio jack, sound is normal, and works fine. The sound will not play properly through the speakers. (I have tried reseating the jack, and re-plugging in the audio adapter)

Occasionally sound plays normally through the speakers. However, I’m unable to reproduce the conditions to restore sound. It sometimes happens when I try playing sound through several AppVMs simultaneously. In those cases, sound is functional until I reboot.

I tried adding kernel-latest and kernel-latest-qubes-vm to Dom0. I’ve tried 6.6.2-1 and 6.6.9-1 kernels without any improvement to the sound.

What are the suggested steps to take to troubleshoot R4.2 sound issues? I didn’t want to try too many of the temporary solutions I found in the forums in case they might make the situation worse.

Did you check sound in another OS to make sure that it’s not a hardware problem?
You can boot from some Live OS USB (e.g. Fedora Live) and check the sound there.
What’s your hardware?

This is a desktop workstation with a SuperMicro motherboard with built-in audio. The same machine has run Qubes R3.x & R4.0 for years without audio issues. The difference now is a clean install of Qubes R4.2.

I did disconnect, clean, and reconnect the audio cable (3.5mm jacks) that connects my external speakers from the Line-Out jack.

Occasionally something in software does get the speakers working correctly. Lately I have not been able to reproduce this at all. Sound from the speakers is garbled and crackly, with very low volume.

It was an old worn out audio cable.

Thanks @apparatus for the inspiration to re-check the hardware.