Erm. If you own the DVD yourself you can google up programs to rip the audio as wav files - I suppose that'd count as making a personal backup. The issue of "where can i download audio from official releases online" is something I'd rather not have come up on the forum, lest the ire of PM be re-awakened.
I'm not judging you one way or the other, just don't think this is the appropriate place for your question.
