What is the cleanest way to add sound to Freeway website
If you have set HTML level to HTML5 (in document settings, or in the output pane of the Inspector palette for a master or instance page) you can import audio files as HTML audio elements.
There is also a YouTube Action that allows you to add content from YouTube.
Freeway also supports QuickTime for earlier versions of HTML, but that’s not a good option (it won’t work for most people).
I’m not sure about background sound. Most people don’t want websites to play music automatically, and Apple tries to prevent this from happening on iOS devices (autoplay is disabled unless a video is also muted). The Mac version of Safari allows users to mute tabs or windows that play music without their permission.