Running Debian sid and it mostly works (still struggling with Nvidia drivers for video). Last night I was watching a video and everything was fine, sound worked. Son was in room “asleep”. I left to use bathroom and then he came looking for me. I don’t know what happened while I was in bathroom but now I hear nothing out of speakers. If I reboot into windows sound works so it’s not a physical issue. Reboot back into Linux no sound. Boot off flash drive Linux, no sound but I think that was always true and was a alsamixer issue on flash drive Linux setups. Volume on YouTube turned to 100, verified not muted, volume in KDE at 100 and not muted. Physical volume on speakers at 100, volume knob on keyboard at 100 and mute not engaged. All volume sliders in alsamixer maxed out. Simple setup, 2.1 speaker system plugged into sound output on motherboard no mixer or fancy equipment.
Son is non-verbal and severally autistic so I can’t ask him. Whatever happened was almost definitely an accident but I can’t figure out what happened. I see like a lighter bar moving on the KDE volume slider which seems to match expected video audio so I believe KDE is receiving the signal to play sound but nothing comes out of speakers. He struggles to feed himself soup or cereal so it’s not like he found some super secret command and is playing joke. Something seems to be accidently hit and is blocking sound… Maybe a mute hot key not synced to main audio controls so it’s not obvious that it’s active???
Edit… This is solved. KDE mixer and alsamixer made no change but changing the output in pavucontrol fixed it. I have no idea why or how. Thanks for everyone who recommended it.
Problem nearly as old as Linux itself:
My suggestion is to try pulse audio volume control (pavucontrol), you get a pretty decent number of options to look through and troubleshoot, in case it’s routing to non-existent display monitor speakers or like a separate headphone jack instead of Lineout, etc.
Pavucontrol fixed it, don’t know why or how but it’s fixed now.
It’s quite a magical tool, in my opinion.
What other magical features does it do?
Lets you change audio input and output device and level per application on the fly.
I could see uses but I don’t have any of those. Typically it shows videos and occasionally lichess matches that’s about the max of what it’s used for.
My monitors have (really bad) speakers so I would hear something. I’ll try to install pavucontrol and see if it helps.
Try making the volume really loud, had some devices not working until sound was above a threshold, like an offset, for no apparent reason
Everything is at 100