You can make your screen "blink" by refreshing it.
for (( i=1 ; i<=5 ; i++ ))
xrefresh -solid blue
xrefresh -solid red
xrefresh -solid green
This should get your attention and get you in the mood for some epileptic dancing. Tune it up or down to your liking or just use part of your screen (-geometry option).
I encountered a slightly different (but likely related) version of this problem. While setting up my audio on the Aorus Matster, I noticed that my speakers were not producing audio while my subwoofer (plugged into the C.Sub jack) was. Oddly enough, if I unplugged the speakers, the subwoofer would stop too.
In my case, using hdajackretask to change the ...
The person who says "alsa is deprecated" is incorrect. Pulseaudio is a sound daemon that runs on top of ALSA. ALSA is still there under the hood.
But it is true that your problem might be due to pulseaudio. Open pavucontrol and mess around with the options in there, that might help you.