In recent Ubuntu versions, I noticed that system beep sound in the terminal is disabled due to some reason. I searched how to re-enable it but it seems not that easy. Finally I found some workaround for this problem from this link. So, in this post, I'm just writing down the steps I followed to enable system beep. Open a terminal and enter following commands.
pactl upload-sample /usr/share/sounds/ubuntu/stereo/bell.ogg bell.ogg
pactl load-module module-x11-bell display=:0.0 sample=bell.ogg
xset b 100
Now, system beep should work. I can try it by entering following line in the terminal and enter.
echo -e '\a'
Following content can be saved as a shell script and used to continuously play system beep.