Low or No Background Audio

About

Version:	WCAG 2.0 and up
Number:	1.4.7
Level:	AAA
Applicability:	Audio
Requirement:	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.
Guidance:	Understanding Success Criterion 1.4.7 How to meet Success Criterion 1.4.7
Techniques:	G56: Mixing audio files so that non-speech sounds are at least 20 decibels lower than the speech audio content

Purpose

The purpose of this success criterion is to ensure that users who are hard of hearing 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.

Additional Information

The following knowledge base pages provide more information about how to address this success criterion for publishing content:

Audio