Like the difference between CD and audio cassette, the Blu-Ray Disc's UNCOMPRESSED digital audio is MUCH better than DVD can offer. Here's an actual account of an "Uncompressed Audio" experience:
"I was watching 'Alien Vs. Predator' (on Blu-ray) and the sound was freakishly clean. There's a scene where a person climbs the side of an ice wall. You can clearly hear her digging her pick in the ice and the snow breaking apart with the tiny ice fragments. Then her phone rang and I was like, 'Wow!' In the movie theaters there are scenes where it's quiet and something loud is introduced and it startles you. A damn phone ringing was so small but it made me realize what I was listening to. The same thing continued throughout the rest of the movie. When people talk you can hear the distance of their voices. It's so open. Like if they are far away or close and maybe there's an echo or something to it. Little things you would never notice or pay attention to. It feels great to finally HEAR quality as well as see it in movies. I LOVE SOUND. Yeah, people don't know at all what they are missing out on. Everyone just focuses on the picture." - NADIR KHAN
When using the "7.1ch AUDIO OUT", remember that all of your speaker settings (size, distance, position and individual volume) are now controlled by the "MULTI-CHANNEL AUDIO OUT" settings in your Blu-ray Disc player's setup menu.
When using an HDMI cable, make sure your "HDMI Digital Audio Out" in your Blu-ray Disc player's setup menu is set to "Bitstream" and not "PCM".
Don't forget to select the "Uncompressed PCM" or "DolbyTrueHD" or "DTSHD Master Audio" track from the "Languages" Menu of EACH Blu-ray Disc title you sit down to watch it. The discs usually default to standard DVD audio.
There have been several "redux" titles that were released almost 3 years ago (when Blu-ray Disc first appeared). Aside from getting a "sharper" picture, these "redux" titles usually offer much better audio quality, too.
Be sure you pick up the newer (and less expensive) PS3 "Slim" to get the best audio quality from your Blu-ray Discs.
Check for any of the 3 "uncompressed" audio logos on the Blu-ray Disc's package before you buy. Some titles only support standard DVD-quality audio ("Dolby Digital" or "DTS").
WARNING!!! WARNING!!! WARNING!!!
Don't be fooled by the "DTSHD High Resolution" logo found on some Blu-ray Disc players and Home Theater receivers. The "High Resolution" means that all of your "DTSHD Master Audio" soundtracks will get watered down to regular old "DTS" before being sent to your speakers.
Here's a great title (even if you don't like the Rolling Stones) which features all 3 uncompressed HD audio formats ("PCM", "TrueHD" and "Master Audio"). Switching between them during playback is great way to demonstrate the subtle differences between all 3 uncompressed formats.