The Official Red Hat Linux Getting Started Guide Prev Chapter 17. The Keyboard Bell capplet allows you to change the bell sound that is produced by your CPU speaker when a keyboard error or message is sent.
Volume changes the actual volume of the bell.
The pitch slider will change the pitch of the note that is played. By default it is set to 440Hz, or the A above middle C. Duration changes the length of time the tone is played. The Test button will allow you to hear the current settings of your keyboard bell. Enable sound for events will launch any sound files you have set in the Sound Events tab when those events occur. Once you have found a sound file you may press the Play button to test the sound and see if you like it enough to hear it every time the event occurs.