I recently undertook a development job where i needed to create a music player. We decided that the music should be managed from soundcloud.com (let them deal with the storage band width). There was one problem. to make it work in ALL modern browsers there needed to be be at least and MP3 version and an ogg version of each song. Of course soundcloud only provides an mp3 stream. So you wouldn't get any sound in Firefox.
after some trial and error with this. I eventually realised that if I uploaded the songs as ogg files and set it so people can download the song, I could use the download_url for the ogg format and still use the stream_url as the mp3.
This does actually work!.
Just thought it might help someone.