If you don't have an HDMI compatible AVR or pre-pro, all is not lost when it comes to improved sound. I happened to have the opportunity of comparing both the standard DVD and Blu-ray versions of "Iron-Man" along with "Hell-Boy" and "The Incredible Hulk" on my new Panasonic BD-55 plugged into my receiver ONLY thru a coaxial cable. The default soundtrack in Iron Man is "Dolby Tru-HD 5.1" and Hellboy and The Hulk are "DTS Master Audio 7.1".
Maybe it is my ears, but to me, even though the Blu-ray discs were downmixed to their appropriate Dolby Digital and DTS ES soundtracks, I couldn't help but notice a difference between the Standard DVD and Blu-ray versions(on the same player!). In addition to the obvious picture superiority, the sound was LOUDER and the separation was better on Blu-Ray. I don't know why this is the case but I can only assume it is because of the superiority of the original mix done in the more advanced formats. I can't wait to upgrade in order to obtain direct HDMI sound capability.
