Audio on instead of muted for Youtube. At the end of the youtube link you just add either: &mute=0 or ?mute=0. So when the link is clicked, popup comes up and video is not muted. You could have this as a check box in the youtube video options. So that if any video is clicked on, on the website. Audio plays with loaded video. Here is a sample of how it works from my website. The images that are tied to a youtube link will play in a popup.
YecHeadquarters.org
I have to go to every page and fix the links one by one so the audio will play automatically. A lot of work since there's probably 50 - 100 videos.