Solution 1:

You can also turn off the "beep" sound system wide by editing:

/etc/inputrc

using your favorite text editor (vi, pico, mcedit..) and add:

set bell-style none

Additionally create a file:

touch /etc/bash.bashrc.local

and add the following:

setterm -blength 0

Solution 2:

Add this line to the file /etc/modprobe.d/50-blacklist.conf

blacklist pcspkr

an reboot

Still beeping?

Sometimes alsa creates a "beep" device. use alsamixer and hit F6 to see all devices. Mute the beep and then use "alsactl store" to save this config.