Understanding Success Criterion 1.4.2: Audio Control

If any audio on a Web page plays automatically for more than 3 seconds, either a mechanism is available to pause or stop the audio, or a mechanism is available to control audio volume independently from the overall system volume level.

Since any content that does not meet this success criterion can interfere with a user's ability to use the whole page, all content on the Web page (whether or not it is used to meet other success criteria) must meet this success criterion. See Conformance Requirement 5: Non-Interference.

Intent of Success Criterion 1.4.2: Audio Control

Individuals who use screen reading software can find it hard to hear the speech output if there is other audio playing at the same time. This difficulty is exacerbated when the screen reader's speech output is software based (as most are today) and is controlled via the same volume control as the sound. Therefore, it is important that the user be able to turn off the background sound. Note: Having control of the volume includes being able to reduce its volume to zero.

Playing audio automatically when landing on a page may affect a screen reader user's ability to find the mechanism to stop it because they navigate by listening and automatically started sounds might interfere with that navigation. Therefore, we discourage the practice of automatically starting sounds (especially if they last more than 3 seconds), and encourage that the sound be started by an action initiated by the user after they reach the page, rather than requiring that the sound be stopped by an action of the user after they land on the page.

See also .

Benefits of Success Criterion 1.4.2: Audio Control

  • Individuals who use screen reading technologies can hear the screen reader without other sounds playing. This is especially important for those who are hard of hearing and for those whose screen readers use the system volume (so they cannot turn sound down and screen reader up).
  • This Success Criterion also benefits people who have difficulty focusing on visual content (including text) when audio is playing.

Examples of Success Criterion 1.4.2: Audio Control

  • An audio file begins playing automatically when a page is opened. However, the audio can be stopped by the user by selecting a "silent" link at the top of the page.
  • A Flash splash page with sound that plays and then stops in less than 3 seconds.
  • A Flash splash page with sound that plays automatically includes a control at the top that allows users to turn the sound off.

Resources Success Criterion 1.4.2: Audio Control

Techniques for Success Criterion 1.4.2: Audio Control

Sufficient Techniques

  1. Playing a sound that turns off automatically within three seconds
  2. Providing a control near the top of the Web page that turns off sounds that play automatically
  3. Playing sounds only on user request
  4. SL24
  5. Providing a control to turn off sounds that play automatically in Flash
  6. Using screen reader detection to turn off sounds that play automatically
  7. SL3

Advisory Techniques

  • Providing a site-wide preference to turn off audio in addition to providing a control near the top of the Web page that turns off sounds that play automatically (future link)

Failures