If you're interested in sound in WebUI games, you can take a look at my
websound extension. It adds support for HTML TADS style sound tags using
SoundManager 2. All the features are supported except fades.
There's currently a bug with the TADS server implementation that affects audio streaming. Although the VM is multi-threaded and requests for each session are handled separately, within a given session only one request can be transferred at a time. Streaming an ogg / mp3 file will block the UI until the download is complete.
This is slated to be fixed in 3.1.1. In the meantime the workaround is to host the files outside of the story file, and put a full URL in the sound tag rather than a relative URL.