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:
The purpose of this success criterion is to ensure that users who are hard of heading can distinguish speech from any background sounds.
How to Meet
Authors need to ensure that any audio of speech (not including musical expressions) has no background noise, the background noise can be disabled, or the background noise is at least 20 decibels lower than the speech.
Note that this success criterion only applies to audio clips. It does not apply to audio in a video, interactive game, etc.
The following knowledge base pages provide more information about how to address this success criterion for publishing content: