Run echo -e '\a' in konsole
There’s a bell icon shows on tab bar, but no sounds
I would think your distribution has helpfully disabled the pcspkr module from loading like all of the Ubuntu distributions among others do by default. To test my theory use sudo modprobe pcspkr to load it and try again. If you have an actual speaker in your machine it should work. The default area to find the blacklisted module is in /etc/modprobe.d/ directory. This is also where you can create file to have it loaded on boot for you to use.
Hi! Just to double-check, have you looked in the Settings menu > Configure Notifications within Konsole?
Playing an audible sound is disabled by default for a system bell, and there’s no desktop notification (other than the tab bar icon) by default if you’re already focused on the session that emitted that bell - but both of those settings are customizable 
This still doesn’t work actually. We can choose one fine sound file and press that |> play button, this will play expectedly. But echo -e '\a' won’t play the sound when having a bell icon shown.
Just checking, was that enabled through the “Play a sound” checkbox, and done for the “Bell in Focused Session” notification?