What is the difference between Dolby Digital EX and THX Surround EX offered by ONKYO. I'm looking at the OUTLAW 950 set-up and the ONKYO TX-DS797 http://www.onkyousa.com/show_features.cfm?class=receivers&m=TX-DS797
I know that these two receivers are not the same! I'm just asking about the audio format.... THANKS IN ADVANCE!