Low or No Background Audio
Success Criterion 1.4.7 (Level AAA)
For pre-recorded audio content, have background sounds been removed, or has a way for users to turn off or lower background sounds been provided?
Why is this important
Background noises in audio only content can distract or inhibit a listener’s ability to comprehend the primary speech content (foreground). Providing listeners with the option of reducing or eliminating the unnecessary background track can make audio tracks more accessible.
Whom does it benefit?
As a person who is hard of hearing and has difficulty distinguishing someone talking from
I want to listen to audio recordings without any background sounds
so that I can clearly hear the primary speech content.
As a person with a cognitive disability who is easily distracted,
I want to decrease or eliminate the background noise
so that I can focus on the most important content.
As a person listening to content that is not in my native language,
I want to have the ability to turn off the background audio
so that I can focus on only the words I am listening to as needed.
What should you do?
- Use pre-recorded audio content that has no background sounds.
- or -
- Allow the user to turn off background sounds.
- or -
- If background sounds are required then they should be four times quieter than the primary speech content (foreground).
How do you do it?
- If possible, remove all background sound from pre-recorded audio content, or re-record the audio content without background noise.
- Use pre-recorded audio that is separated into multiple tracks. Use an audio player that allows the user to mute background tracks.
- When recording audio files, mix the tracks so that the background content is at least 20 decibels lower (four times quieter) than the foreground content.
Need technical guidance?
Additional Resources to help you:
- Audacity - Free, open source, cross-platform audio mixing software
- About Decibels (dB) - by Greg Vanderheiden
- Example of audio foreground 20 decibels higher than the background - sufficient
- Example of audio foreground 2 decibels higher than the background - not sufficient