1.4.7 Low or No Background Audio Level AAA

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.

[View on W3C.org]

Testing & Remediation

How to test: Open any prerecorded audio-only content that you have on your site. Listen to it to hear if there is background sounds. If there are, can they be turned off by the user? You can also measure the volume of the audio (both background and foreground) in dB(A) SPL. Subtract the values and check that the result is 20 or greater. How to remediate: When posting prerecorded audio-only content, ensure one of the following are complete:
  • The content has no background sounds
  • The content's background sounds can be turned off
  • The content is created by mixing audio files so that non-speech sounds are at least 20 decibels lower than the speech audio content

Questions and Answers