Blu-ray has PCM stereo and DTS 5.1, which should be better?

PCM is higher resolution. But, it's only stereo on that disc. DTS is lower quality. But, it's discrete 5.1.

With movies, where surround effects are important, I select DTS or DD 5.1. With music, where surround is mostly ambience, I select PCM and then use PLII music to generate surround sound.

Yes, with concerts, when the choice is stereo PCM or lossy multichannel, I usually choose stereo PCM. If the multichannel track is lossless TrueHD or dts-MA, then I select that instead.

Without going into a lengthy explanation, PCM is the fundamental digital format used for home entertainment audio. DD 5.1 and DTS are not audio formats. They can't be "played" to produce sound. They're really just zip files designed to save space. A big PCM file is zipped up into a smaller DD 5.1 or DTS package and then unzipped back into PCM to be played. But, these lossy codecs squeeze the original so much that some of it can't be recovered. The PCM that comes out is less than the PCM that went in. That's why the output of a lossy codec usually doesn't sound as good as the original PCM.

That's understandable. DVDs and CDs don't support multichannel PCM. Plus, the optical and coax connections used on DVD and CD players are limited to stereo PCM. But, there are no such limits with Blu-ray discs and HDMI connections, which can handle multichannel PCM.

.....and the lossless compressed audio formats TrueHD and DTS MA-HD.

I wouldn't worry about triing to understand it too much. I was that way several months ago, back in May when I finally broke down and bought a 7.1 receiver to go along with my bluray player.

I had purchased the movie, Cars on bluray and didnt understand the difference between Dolby Digital 5.1 and the pcm track. I understood that the truehd and master hd-dts tracks are the best sounding, but from what I read the pcm track should have sounded better with better sepeation than the DD. Plus the volume of the pcm track was no where close to the DD track. I made a post about it, I though maybe on the disc itself the tracks were listed wrong. But nope, thats the way the pcm track sounds. Heck, I even went out to Best Buy and told them something was wrong with the audio tracks and they exchanged the movie for another one. I still thought maybe the audio was messed up on my bluray disc.

And after several people posted that the pcm track is better, and this was on a few different sites, I can't help it, I prefer the DD track. I watched the movie several times with each track, even went back and forth. Even with the volume turned up on the pcm track, I still prefer the DD. In my opinion, there was no comparison between the 2 tracks. Now when I have the option between DD and the master hd-dts tracks, the master tracks always sound better.

I actually had some friends come over and my brother. I didnt tell them which soundtrack was which, and I really didnt explain anything, other than I was going to have then watch a small portion of the movie twice and I wanted thier honest opinion which version sounds the best to them and why. I played the movie for about 10 mins w/ the pcm track and then the same 10mins with the DD.

Everyone said they preferred the DD track. They all said the same thing. Better seperation, sounded crisper, ect. So, I'd say whichever track you think sounds the best to your ears, go with that one. Cars is the only movie I own on bluray that doesnt have with a master hd-dts or truehd track. It has the pcm track instead, which Im not impressed with at all.

So, go figure.

Your logic (and A/B testing) is flawed since all TrueHD and DTS-MA tracks are the LPCM track compressed. After decoding (un-compression) LPCM, TrueHD and DTS-MA are 100% bit for bit identical. On the other hand DD (and DTS) are the LPCM track perceptually coded (most information data removed and thrown away).

I understand all that. All I know is the DD track sounds better on Cars than the PCM track. Don't ask me why or how...I dont know. And yes, the receiver even displays the track being played.I dont get it either.

Maybe a silly question and not meant to insult, but have you checked all of the settings on the player and receiver? Is the uncompressed PCM track actually being sent out as such? Is the player or the receiver downconverting to PCM stereo and then being processed through Pro LogicII or IIx? I know there are some receivers that can decode DTS HD Master Audio and Dolby True HD but cannot do a thing with uncompressed PCM except to down convert to PCM stereo and then process it using Pro Logic or DTS neo:6. I own several uncompressed PCM titles and they are actually my favorites. I used to use "Cars" as a video and audio demo for friends.

Forgot to say that I was talking about uncompressed PCM 5.1, not stereo.

What AVRs work as you describe? I've never heard of such a thing.

A receiver that has lossless decoders will not downmix multichannel PCM to stereo unless instructed to do so by the user. That would pretty much only happen if the AVR were configured for two channels and then it would not be possible to apply a multichannel DSP such as PLII.

Confused some posts while reading. Is the original poster using optical/coaxial or HDMI connections? LPCM stereo can be processed with Pro LogicII through HDMI, but uncompressed PCM 5.1 cannot be. Through optical/coaxial output, PCM 5.1 would come out as two channel and could be processed with Pro LogicII and display as much. Using HDMI, uncompressed 5.1 should display as multi channel in. Made some errors for sure in my post. Had DSD on the brain, but that's another can o' worms. Sorry folks. Throw rotten fruits and veggies here. Can't figure how wizard's Dolby Digital track sounds better than the PCM 5.1 track.

I believe I posted this already right above your post. And no, I would never be insulted. I can openly admit when Im wrong about something. I love learning things. But yea, there is not anything to change on the receiver, it automatically plays whatever track I choose on the bluray player. And I checked the manual for the bluray player to make sure I had the settings right. Heck, I even tried using the optical cable instead of the hdmi cable when listening to the audio tracks. Plus my receiver displays the audio track being played, whether its master hd-dts, DD5.1, PCM track. And when I have Cars in, and I choose that track, yes the receiver is displaying that is the track being played. I really dont understand the problem. When listening to a master hd-dts 5.1 track, it sounds waaay better than a DD5.1. So, shouldnt the PCM track sound the same way, waaay better than the DD5.1 track. It doesnt.

I understand you asking if the receiver is actually decoding the track. My reciever decodes every single type of audio track that there is, or at least that Ive ever heard of. Its brand new, just bought it in May. In another thread awhile back, and I think it was on a different site, someone else asked me the same thing. The only thing I was thinking was that the bluray player was not decoding the pcm track, but if that was the case then the receiver would not be displaying that the PCM 5.1(48 kHz-24-bit) was the one I was listening to.

And that is what my receiver displays, PCM 5.1 48 kHz-24bit. Ive actually racked my brain over this. And I almost(almost) wish I would have never bought the damn movie now. I'll be honest, if I ever go to buy another movie and if the only audio track it has is the PCM track, I seriously doubt I buy that movie. Overall, it really shouldnt be that big of a deal, but the damn track should sound the same way all my master hd-dts, truehd, ect tracks sound. They all sound waaaay better than the DD track, and I feel the PCM track should sound the same way as those tracks.

Heck, Id give someone $100 if they could come over and figure out whats going on. Im serious. Like I said, in the end, it really shouldnt be as big of a deal that Im making it out to be. Its only a damn movie. But I know how the track should sound, and when the DD track sounds better, something has to be wrong. And like I mentioned in an earlier post, everyone who listened to both tracks, all choose the DD track hands down as the best track, it wasn't even close.

I almost wish I wouldnt have brought this up again. I don't like it when my mind becomes boggled, and I know something just isnt right. Oh well. Just one more unsolved mystery in my life. I always have the weirdest things happen to me.

PCM is often output several dB lower than soundtracks decoded in receivers. Volume matching may fix things up. Another possibility is the processing your receiver does after decoding the track. By processing, I mean functions such as room correction. If the processing is different between the PCM and lossless inputs, the outputs will sound different.

What happens if you decode a lossless track on your player and output it as PCM. Does that sound the same as decoding the track in your receiver?

??

DD 5.1 and DTS use data compression, not dynamic range compression, and the two processes are not the same. Data compression is a zipping process designed to save space. Much of what is removed during compression is restored during decompression.

I wasn't implying that dynamic range "compression" is the same as data compression, or that the word compression is of the same meaning in both...

However, I was under the impression that DD loses dynamic range through the encoding/decoding process vs. the original soundtrack. And I was wrong. It seems the nominal level and dynamic range is able to be altered during the process but can be carried over unaltered. IF these levels were altered in the "Cars" DD soundtrack, then it could be affecting gamewizard's opinion of DD vs. PCM, and this was the reason for my post.

One thing I had to get used to with the new lossless formats was, when watching movies at night, how much I needed to keep adjusting the volume between soft dialog and sudden flurries of action. It sure seemed as if the range of soft-loud was much greater in the new formats and PCM.

I stand corrected. Post deleted.

Try "night mode" on your decoding device. It applies DRC to deal with that situation.