Low or No Background Audio
Summary:
WCAG 1.4.7, "Low or No Background Audio," specifically addresses the need for clear audio communication in pre-recorded content. It ensures that speech in audio tracks is easily discernible, particularly for users who are hard of hearing or have auditory processing difficulties.
What:
This guideline requires that any pre-recorded audio content (excluding captions) that contains speech should have either no background sounds or the background sounds should be at least 20 decibels lower than the speech. This is about a 4 times decrease in volume, making the speech the primary focus.
Why:
Background noise can significantly hinder the ability of many users to understand spoken content. This is particularly true for people with hearing impairments or those who find it challenging to focus on speech with competing sounds. Ensuring clear speech in audio content makes the information accessible to a wider audience.
Examples and Scenarios:
- Educational Videos: A tutorial video should have minimal to no background music or noise to ensure that the instructional speech is clear.
- Podcasts: In podcast episodes, especially those focusing on informational content, background sounds should be significantly lower than the speaker's voice.
- Promotional Videos: Marketing or informational videos should prioritize speech clarity over background audio to ensure the message is accessible to all viewers.
How to Comply:
- Video Production: During editing, adjust background music or ambient sounds to be much lower than the speech. Use audio editing tools to measure and balance levels.
- Audio Content: For audio tracks in apps or websites, like narrations, ensure that background sounds are minimal or absent.
- Multimedia Presentations: When creating multimedia presentations with voiceovers, maintain a clear distinction in volume between the speech and any background audio.
Exceptions:
- Music and Entertainment: If the primary purpose of the audio is for music or entertainment rather than speech communication, this guideline might not apply.
- Sound Effects: Essential sound effects that are part of a narrative or crucial to the content may be exempt if they are brief and necessary.