FreeBSD has one really annoying "feature": The system bell is activated by default. Whenever you press backspace on an empty command line, there will be this annoying beep. Luckily it can be turned off quite easy. Open a shell and enter

sysctl hw.syscons.bell=0

as root. That's it! If you want to make your changes permanent, you'll have to change your /etc/sysctl.conf. But this is easy, too. Just add the line "hw.syscons.bell=0" to the file and you are fine. You can do this with:

echo 'hw.syscons.bell=0' >> /etc/sysctl.conf