If silverlight works, use it.
I was just wondering, because I remembered about having just one index file and you mentioned it again, if having an iframe would work. If so, you could use a standalone page for the sound without jQuery mobile on it and have it show through onto the main page via an iframe. That would greatly reduce the chance of a conflict with jQuery mobile, which could still be used on the index page. The sound page would of course have to be in the same folder. If that can work, it would be a good solution. Setting the proper width and height for the iframe might be tricky. But since you should know what those requirements are, it shouldn't be too hard. Something like:
On the page in the iframe, set the body and/or html to overflow hidden. That in combination with the scrolling no attribute will get rid of any scrollbars on it, making it look more like part of the top page. Or you can use just overflow-x hidden to allow for a vertical scrollbar if/when needed.
<iframe src="sounds.htm" width="100%" height=500 scrolling="no"></iframe>
This all assumes that an iframe is allowed for this sort of thing you're doing and will work. But if so, it's one of the best way to avoid script and css conflicts while still having only one page. An object tag can also be used to show one page in another. It's less reliable cross browser (older IE and Opera act weird with it), but should work on mobiles and tablets. If an object tag is used, the syntax is different.