More InformationDesign Specifications and Guidelines - Special Design Considerations
You can incorporate sound as part of an application in several ways — for example, music, speech, or sound effects. You can use this auditory information for a variety of purposes:
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For information about creating standard system sounds or registering your own sound events, see Chapter 11, "Integrating with the System."
When used appropriately, sound can be an effective form of information and can enhance your interface. However, avoid using sound as the only means of conveying information. Some users may have hearing loss. Others may work in a noisy environment or in a setting that requires that they turn off sound or maintain it at a low volume. In addition, like color, the benefit of adding sound to an interface is subjective.
As a result, your best use of sound is as a redundant or secondary form of information. You can also supplement sound with alternative forms of communication. For example, if a user turns off the sound, consider flashing the window's title bar or taskbar button, displaying a message box, or using other ways to bring the user's attention to a particular situation. Even when sound is the primary form of information, you can supplement the audio portion by adding a visual representation of the information, such as captioning or animation, to indicate that audio is playing.
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The taskbar can also provide visual status or notification information. For more information about using the taskbar for this purpose, see Chapter 11, "Integrating with the System."
Always allow the user to customize sound support. Provide support for the standard system interfaces for controlling volume and associating particular sounds with application-specific sound events. You can also register your own sound events for your application.
Users can indicate that they want a visual representation of audio information by selecting the Use ShowSounds check box. Your software should query the status of this setting and provide captioning for the output of any speech or sounds. Captioning should provide as much information visually as is provided in the audible format. It is not necessary to caption ornamental sounds that do not convey useful information.
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The GetSystemMetrics function provides access to the ShowSounds and SoundSentry settings. For more information about this function and the settings, see the Microsoft Platform SDK on the MSDN Online Web site at http://msdn.microsoft.com/ui/guide/sdk.asp.
Windows Media Player provides support for closed captioning using the Synchronized Accessible Media Interchange (SAMI) standard. This makes it easy for anyone to enhance multimedia content with closed captions for people who are deaf or hard-of-hearing, and with descriptive narration for users who are blind. For more information about Windows Media Player, see http://www.microsoft.com/windows/mediaplayer/. For information about SAMI, see http://www.microsoft.com/enable/.
Do not confuse ShowSounds with the system's SoundSentry option. When the user sets the SoundSentry option, the system automatically supplies a visual indication whenever a sound is produced. Avoid relying on SoundSentry alone if the ShowSounds option is set. SoundSentry provides only rudimentary visual indications, such as flashing the display or screen border, and it does not convey the meaning of the sound to the user. The system provides SoundSentry primarily for applications that do not provide support for ShowSounds. The user sets either of these options in Accessibility Options in Windows Control Panel.
Note
In Microsoft Windows 98, SoundSentry works only for audio output directed through the internal PC speaker and does not support multimedia audio output.
Fundamentals of Designing User Interaction
Design Specifications and Guidelines