Welcome to the party!! <img src="{SMILIES_PATH}/icon_e_biggrin.gif" alt=":D" title="Very Happy">
Sorry but I been facing similar issues on my Windows Phone 8.1 game.. and apparently its Microsoft's problem. They have a crappy Audio support in their WP Internet Explorer. Ashley and me have been trying hard to get MS's attention to fix this damned issue!
Here is the Post I created about a month ago:
viewtopic.php?f=151&t=115447
Look for the IE Connect link created by Ashley.
Currently this guy from MS is working on the issue (After we bothered him all day)
https://twitter.com/deltakosh
I request you to visit his twitter and do the same!! Tweet him (and other MS IE devs ) your problem until they get serious about finding a fix!! <img src="{SMILIES_PATH}/icon_e_biggrin.gif" alt=":D" title="Very Happy">
BTW.. he has been really nice and helpful, so be nice too <img src="{SMILIES_PATH}/icon_e_wink.gif" alt=";)" title="Wink">