Baronlando said:

The audio for all the films was tweaked. It was readily apparent that it was a labor of love for Matthew Wood who worked with Ben Burtt. Episode 4 got the most attention since originally it was a mono mix with no separation.

Anybody else very confused by this?

It might have it's genesis here:

Burtt says. "On Star Wars, everything--music, dialogue, effects--was combined into one master recording. You had to undo it and make changes with surgical precision. But on Jedi, we had separated stems: Music was separately recorded from dialogue and from effects, so if we wanted to change something independency of one of the other elements, we could do it."

http://lavender.fortunecity.com/hawkslane/575/starwars-advanced.htm