If you find the System Beep to be annoying (and let’s face it, it is!), you can disable it with a simple terminal command and be system beep free.
1. Open a terminal window.
2. Execute the following command in your terminal window:
sudo rmmod pcspkr
3. Close your terminal window.
Enjoy the absence of the system beep.
If you need to enable the system beep, execute the following command in a terminal window:
sudo modprobe pcspk