On [Mozilla developper website][1]Mozilla developper website you can find the following informations :
- MP4 is supported by IE
- OGG is not supported by IE
- WebM is supported by IE with the addition of a plugin
Anyway, you need to know it is a real pain in the *** to make your audio files working on all browsers. First thing to do is link the 3 formats in order to let the browser chose the one it prefers, but even then you will likely encounter many incomprehensible issues due to the high diversity of browsers, versions, etc...
Note :
Even though it does not answer the question, I think it is worth noting that an easy solution would be not to support Internet Explorer for your game. The majority of people still using IE are either companies or old people. Either way, these people are less likely to play your game, so you should weight out if you are not going into useless troubles trying to make IE support. [1]: https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats