Because Ubuntu’s pc skeaker sound is annoying. Whatever you do, it’ll beep like you’ve done somethings terrible. Just like when you’re chatting in Pidgin, and one more Backspace will make a beep that can make your cat jump out of window. The problem is, most likely pc speaker is much louder than your Ubuntu sound.
I’ll make it quick
gksudo gedit /etc/modprobe.d/blacklist
and append this
Last thing to do, save and reboot.
Ofcourse there are other ways to do this, like modprobe -r, but I think black list is the most “gently” action.
Much appreciate to truonggiang231 in Ubuntu-vn.org forum for the instruction.