Perceivable Guideline 1.4 Distinguishable

1.4.2 Audio Control

Sound that starts by itself must be easy to stop

Level A 1 automated check

What it asks for, in plain English

If a page starts playing sound on its own and it lasts more than three seconds, there has to be a way to pause it, stop it, or turn its volume down separately from the whole system, and that control has to be near the start of the page so it can be found quickly.

The reason is that a screen reader is also sound. Background music or an autoplaying video talks over it, and the person cannot hear their screen reader to find the mute button.

The simplest way to meet it is to never autoplay sound. If a video must autoplay, start it muted.

This is an independent explanation. The binding wording is the W3C Recommendation, and the W3C's own Understanding 1.4.2 page has the full intent, techniques and definitions.

Who it affects

Someone using a screen reader lands on the page, music starts, and they can no longer hear the screen reader telling them where the stop button is.

A person with an attention or sensory processing difference finds sudden unexpected sound distressing and leaves.

Anyone in a library or a meeting scrambles to close the tab.

How to check it

  1. Load each page with the speakers on and do nothing. Note anything that starts making sound.
  2. If sound starts and lasts more than three seconds, Tab from the top of the page. A pause, stop or mute control should be among the first things you reach.
  3. Check the control works with the keyboard and is labelled so a screen reader can find it.
  4. Check embedded players, hero videos and chat widgets, which often autoplay with sound by default.

What Websight checks for 1.4.2

Websight runs this automated check for 1.4.2:

A Sound must not start playing on its own no-autoplay-audio If a page starts playing sound by itself and keeps going for more than three seconds, it needs a way to stop or mute it before anything else on the page.

Websight can only spot the obvious markup case: an <audio> or <video> element set to autoplay with no controls. Sound started by script or inside an embedded player is invisible to a scanner, so load the page and listen.

Practical tips

  • Do not autoplay sound. If a background video is wanted, mute it and let the person unmute.
  • Keep the native controls on media elements unless you provide better labelled ones of your own.
  • Put any mute control at the top of the page, before the navigation.

Scan your page and see where 1.4.2 stands

Websight gives a score out of 100, explains each automated finding in plain English, and lists the checks a person still needs to do.

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