1.4.7 – Low or No Background Audio (Level AAA)

Audio-only content is clear with no or minimal background noise.

Introduction

Some users have difficulties with their hearing and won’t be able to hear your audio content as clearly as others, especially separating speech from background audio.

You can help by ensuring that your audio is clear. If you have pre-recorded audio-only content, keep background noise to a minimum so that the speaking voices can be heard.

How to Pass

• Make sure your pre-recorded audio doesn’t contain any background noise; or
• If there has to be some background noise, it’s generally 20 decibels lower than the foreground noise. That’s about four times quieter.

Exceptions

Background noise is acceptable if:

• The audio isn’t mainly speech (for example, in an audio play, an action scene might have a helicopter blown up by a car)
• The audio is part of a CAPTCHA element (CAPTCHA is a test that separates humans from spambots and is often used in forms)
• The audio is you “singing or rapping” (seriously, this is a direct quote)
• The background sound can be turned off (but it’s better just to comply than add complexity)

Tips

Record your audio in a place you know will be quiet (a room with lots of soft furnishings is best if you haven’t got a studio).

Only use good quality audio (you should be doing this anyway if you care about your website).

See Also

• Understanding Success Criterion 1.4.7 (W3C)