I'm honestly not sure whether this is properly an issue of my distro (MX 16) or my desktop environment (XFCE). At some point in an earlier version of my distro (again, I'm not sure the distro has anything to do with it), the audio was set to instantly cut out if my headphones were unplugged form the audio jack. This was useful for preventing me from inadvertently annoying people with noise in a library or other public place expecting quiet. My current installation of the distro won't do it anymore. I no longer remember what setting it was, and have been unable to find it again. I thought it was the "auto-mute," but I tried it and it doesn't appear to accomplish what I'm describing.

I just had the scenario described: I was in the college library listening to music on headphones while studying, and suddenly noticed my headphones weren't fully plugged in. Nobody actually came over and told me to turn it off (and thus I wonder if they actually heard anything), but I'm still pretty embarrassed. (This, after I was just grumbling to myself about how stupid the school is to have maintenance trimming the trees outside the library with noisy tools in the middle of the day.) At least I don't listen to very loud or disruptive music.

I did already ask in my distro forum (not on LQ), but no one had any suggestions, possibly because it's not the distro's fault.

yes it is. it's just a feature they care not to figure out how to do, if they had even thought of such a thing.
if you are using pulse audio and it can tell when you have headphone or speaker on, then you too can gain this information by whatever means they do, then exploit it to your benefit to mute your speakers whenever the right condition(s) occurs. or you can look into how to mute your speakers permanently and not your head phones.

so yeah there is a clue to look into.

http://terokarvinen.com/2015/volume-...and-line-tools
and
https://askubuntu.com/questions/4378...o-jack-enabled
for starters

1 members found this post helpful.

anything in alsamixer can also be managed with amixer commands

For example, to set speaker volume to zero on my laptop:

• set auto-mute in alsamixer to disabled (stop any audio switch / level change for headphones and speakers)

• then set level on speakers to 0

to save it as permanent setting:
your system may need different audio card number and ALSA mixer element names (case-sensitive too)