very good summary here.
http://www.digitaltrends.com/home-theater/ultimate-surround-sound-guide-different-formats-explained/
one thing i like… DD 7.1 and blu-ray quality audio go hand in hand. time for me to give 7.1 a listen again. native, on your home theatre!
THX – is only mentioned in passing as collaborating with DD to create their standards, also good 🙂
the only reference to THX surround sound in home theatre i can find is… DD “EX”
http://www.timefordvd.com/ref/THXSurroundEX.shtml
so… that’s a good thing as well. DD is doing a fine job already, if the folks at THX have something to add all the better.
but it still begs the question. what does THX think it’s adding by putting their name on other peoples Blu-ray movies, all 5?!