WCAG Guideline 1.4.7: Low or No Background Audio Explained
Estimated read time: 5–6 minutes
Guideline 1: Perceivable
The Perceivable principle ensures that all users can access and understand content, regardless of their sensory abilities. This includes making sure that speech audio is clear and not obscured by background sounds.
Guideline 1.4: Distinguishable
Guideline 1.4 focuses on making content easier to see and hear. For audio, this means ensuring speech is not masked by music or other sounds.
What Is Guideline 1.4.7 Low or No Background Audio?
"For prerecorded audio-only content that contains primarily speech, background sounds are either at least 20 decibels lower than the speech content, can be turned off, or are not present."
Guideline 1.4.7 Low or No Background Audio is a Level AAA requirement in the Web Content Accessibility Guidelines (WCAG) .
- Speech must be clearly distinguishable from background sounds.
- Background audio must be at least 20 dB lower than speech, be removable, or not present.
- Applies to prerecorded audio-only content (e.g., podcasts, lectures).
For more, see BOIA: How Background Noise Affects Accessibility .
Why Does It Matter?
- Clarity: Background sounds can make speech hard to understand, especially for users with hearing loss.
- Inclusivity: Ensures everyone can access spoken content.
- Legal Compliance: Low or No Background Audio is a Level AAA requirement in WCAG 2.2.
- Usability: Clear audio benefits all users, especially in noisy environments.
What Needs to Support Accessible Audio?
- Podcasts and audio lectures
- Prerecorded audio-only content
- Any speech-based audio files
All must ensure speech is not masked by background sounds.
How to Meet Guideline 1.4.7
- Mix background audio at least 20 dB lower than speech
- Provide a version with no background audio
- Allow users to turn off background sounds
- Test with users who have hearing loss
For more, see the W3C's Low or No Background Audio Techniques .
Common Mistakes to Avoid
- Background music too loud compared to speech
- No option to turn off background sounds
- Not testing with users who have hearing loss
Differences Between A, AA, and AAA for Guideline 1.4.7 in WCAG 2.2
- Level A & AA: No requirement for background audio in speech content.
- Level AAA: Requires background audio to be at least 20 dB lower than speech, removable, or absent.
For more, see the W3C’s official documentation for 1.4.7 Low or No Background Audio .
Quick Checklist
- Speech is always clear and distinguishable
- Background audio is at least 20 dB lower than speech
- Option to remove or turn off background sounds
- Tested with users with hearing loss
Summary
Guideline 1.4.7 ensures that speech in audio content is always clear and accessible. Keep background sounds low or removable to support all users.
Accessibility means everyone can hear your message—don’t let background noise get in the way!