Question: The [ping manual](http://manpages.ubuntu.com/manpages/maverick/en/man8/ping.8.html) says that `ping -a` will generate audible pings, but when I try this no sound is made.

What am I doing wrong?

Answer: 
`compiz` "eats" the sound and *this is a reported bug*, so it won't work in the graphical interface in standard `compiz` ubuntu sessions. (see [this bug report](https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/537703), thanks to Dylan McCall comment for the URL).

If you really need the functionality, you could run your `ping` from a physical console (`Ctrl`+`Alt`+`F1`). But don't forget:

```
sudo modprobe pcspkr

```

As module `pcspkr` isn't loaded at boot time and actually drives the old PC speaker you should have in your computer.

You can add it to `/etc/modules` if you think you'll need it at a regular basis as this will have the effect to tell the system to load it at boot time.

**Note:** as it's a `compiz` issue, if you are using `gnome-fallback` session you shouldn't experience the issue. If this is the case, check your terminal program for options related to console bell.
Because the question is not specified for Unity only, I'll make a little hint about KDEs Konsole. You just should specify a sound for a "Bell in Visible Session" which is under *Settings -> Configure Notifications*. For example I'm using sounds from */usr/share/sounds/* section. I don't remember is there such an option in Ubuntu's Unity terminal.