Is User Triggered Background Audio Acceptable?

Question

We're designing a web presentation for a client, and the subject of including "white noise" background audio (crowds etc) after a video has finished to enrich the presentation and tie the different elements together has been discussed. This will only be triggered when the user starts the presentation, and there will be an option to mute the audio throughout.

My question is, is this acceptable? Will background noise used in this way annoy users?

Any advice would be appreciated here, I can't find much about using audio on websites in this context. It would also be a huge benefit if anyone can suggest links/articles that support their case one way or the other.

Answer 1

It sounds like it has the potential to cause confusion if the UI doesn't make it clear where the sound is coming from and how to stop it. If a sound started when I began watching a video, common sense and convention would suggest that the sound will stop when I finish watching the video (either when I stop it manually or I reach the end). If not, I'd probably find myself hunting around to find the source of the sound (In my own experience, unexpected background sounds often mean an avert has opened in a popup or pop-under).

In order to make it clear where the sound is coming from, I would display some sort of video loop or animation after the video presentation has ended and locate the stop/mute control close by.

Caution is needed because depending on the volume and complexity of the audio, there is a risk that it might cause issues for screen reader users. Firstly, it may not be clear that the presentation has ended if the sound continues and secondly, the sound might make it difficult to hear the screen reader. (WCAG SC 1.4.2)