I wanted to clarify that audio track 3 on both Empire and Jedi is not technically a "blend" of both tracks. The 2004 edition is in the left audio channel and the original edition is in the right channel. When using headphones you can distinctly and profoundly hear additional or modified dialog, effects etc... and that's is the purpose for that third track.
However, ANH track 3 is a true blend making it impossible to tell anyting apart. That was a fupar on my part.