Low or No Background Audio
For prerecorded audio content that is primarily speech, background sounds either do not occur, can be turned off, or are at least 20 decibels lower than the foreground speech, except for occasional sounds lasting one or two seconds.
In plain language
In a recorded audio track that's mostly speech, any background sound should either not exist, be possible to turn off, or be much quieter than the speech — not competing with it.
Why it matters
People with hearing loss have a much harder time separating speech from background noise than people with typical hearing. Music or noise at a similar volume to the speaker can make the content impossible to follow, even though it sounds fine to others.
In practice
Fails this criterion
A recorded podcast has background music playing at roughly the same volume as the host's voice throughout the episode.
Meets this criterion
The same podcast either has no background music, lets listeners turn it off, or keeps it quiet enough (well below the speech) that it never competes with the host's voice.
Test it yourself
Listen to the site's speech-based audio content. Is there background music or noise at a similar volume to the speech? If so, and there's no way to turn it off, this criterion is failing.