1.4.7: Low or No Background Audio [AAA]

Description Sufficient Techniques Advisory Techniques Failures Notes

Description

For prerecorded audio-only content that (1) contains primarily speech in the foreground, (2) is not an audio CAPTCHA or audio logo, and (3) is not vocalization intended to be primarily musical expression such as singing or rapping, at least one of the following is true:

No Background

The audio does not contain background sounds.

Turn Off

The background sounds can be turned off.

20 dB

The background sounds are at least 20 decibels lower than the foreground speech content, with the exception of occasional sounds that last for only one or two seconds.

Note

Per the definition of "decibel," background sound that meets this requirement will be approximately four times quieter than the foreground speech content.

Sufficient Techniques

Sufficient Techniques for Success Criterion 1.4.7

Note: Other techniques may also be sufficient if they meet the success criterion. See Understanding Techniques.

• G56: Mixing audio files so that non-speech sounds are at least 20 decibels lower than the speech audio content

Advisory Techniques

Advisory Techniques for Success Criterion 1.4.9

• C12: Using percent for font sizes
• C13: Using named font sizes
• C14: Using em units for font sizes
• C8: Using CSS letter-spacing to control spacing within a word
• C6: Positioning content based on structural markup

Failures

Failures for Success Criterion 1.4.8

• F24: Failure of Success Criterion 1.4.3, 1.4.6 and 1.4.8 due to specifying foreground colors without specifying background colors or vice versa
• F88: Failure of Success Criterion 1.4.8 due to using text that is justified (aligned to both the left and the right margins)

Notes