An audible cue is a sound generated by the computer to draw the user's attention to, or provide feedback about, an event or state of the computer. Audible cues can be anything from a beep to a recorded or computer-generated message, and occur when the user attempts to perform an invalid action or when an event or state of the operating environment requires the user's attention. For example, the system may beep when the user tries to choose a menu item that is not available.
If your application will be used with computer hardware that has advanced audio capabilities, you can specify more elaborate and informative cues, such as speech synthesis. Audible cues are limited only by the available hardware and the usefulness of the cue. However, audible cues should not be intrusive or distracting, and the user should always be able to specify that the audible cues be turned off.
Some users may be unable to hear audible cues due to disabilities or environmental constraints. Therefore, audible cues should always be redundant to or replaceable by visual cues. For example, use an audible in conjunction with a flashing screen.