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Okay, Let's Start Over: Please Explain How These New HD Soundtracks Work... (1 Viewer)

bpickell

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Jan 30, 2008
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Brian
I don't fully understand this yet either, however from what I have read the only true way to actually output the DTS-MA tracks is through an HDMI connection. Or at least that is the information that has been fed to me.
 

Bob_Chase

Stunt Coordinator
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Nov 13, 2002
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101

This is incorrect. These tracks can be passed via the 5.1/7.1 analog connection as well.
 

Nathan Eddy

Second Unit
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Jan 22, 2004
Messages
262
I think this is the right thread for this question . . . I've got the Sony 550 BD player, hooked up to my receiver via the 5.1 analog inputs--no coax or optical at all. From what I'm reading here, it seems that I *might* get better audio on DD 5.1 or DTS tracks by hooking up a coax cable (depending on the quality of my receiver). However, what about a PCM track? Would it sound better, too? Isn't it digital, too? Is it "decoded" like DD or DTS, or just converted into analog? I'm not sure I understand the difference there, or if there even is a difference. If it is decoded, this is done in the player (since I'm sending over analog outputs), right ?

On the latest Rush BD, for instance (Snakes and Arrows concert), I can listen to either the DTS-HD MA track, or stereo PCM. When I select PCM, what exactly is happening as it goes to the receiver over the 5.1 analog outputs? I ask because I can select several "input modes" on my receiver: analog, digital manual, automatic, and 6-channel input. These are the options on a single input selection (the 5.1 inputs, in this case). So while I'm listening to PCM in this way, I can choose to do so either with the "6-channel" choice, or the "analog" choice. (These are the only realistic choices, because selecting "digital manual" gives no sound, while automatic defaults to analog.) When I select "analog," PCM stereo sounds *a lot* better than when I select "6-channel input." There is much more bass, and a fuller sound.

So obviously, this is something my receiver itself is doing, since I'm not changing a thing on my BD player, and the only audio cables I have hooked up are the 5.1 analog. And since these *are* analog cables, I assume that the D>A conversion has already taken place inside the player before sending it out over the cables (and this happens no matter which audio track I select, right?).

So my question is: what exactly is my receiver doing to this PCM signal? If it's already analog--because it's going out/in analog outputs/inputs--then why does it sound so much better when I select "analog" as the input mode? How is this any different from selecting the "6-channel input" option? The cables remain the same. The D>A conversion has already taken place (I assume). So what's left for the receiver to be doing that causes such a drastic difference? It can't even be spreading the sound over all my speakers (thus "diluting" the stereo sound like a DSP), because the sound remains limited to my 2 mains even when I pick "6-channel input" for a PCM stereo track.

My receiver is a low- to mid-range Kenwood VR 6050, about 7 years old.
 

Nathan Eddy

Second Unit
Joined
Jan 22, 2004
Messages
262
Ok, now I'm even more confused. I just did some quick experiments after that last post. I've set the audio priority on my Song 550 to "multichannel." But on my receiver, when I select "aux" as the input, I'm getting sound that is being passed over the HDMI cable hooked directly to my TV (by-passing the receiver), and then going from the TV to my receiver via two RCA cables connected to my TV's analog outs and my receiver's 2-channel stereo analog inputs.

Ok, now for the confusing part: why am I getting any sound through the HDMI at all, when I've set the player's audio priority to multichannel analog outputs? And why does PCM stereo sound *better* through this choice than over 5.1 analog? Even stranger: why does the DTS-HD MA track sound better than the PCM this way? It can't be lossless. I'm not even sure what it is, since it's going out to the TV over HDMI and to my receiver through stereo RCA cables.
 

Stephen Tu

Screenwriter
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Apr 26, 1999
Messages
1,572
PCM = raw uncompressed, unencoded digital sound, as used on a music CD, except that CD is limited to 2 ch 16 bit/44.1khz, while BD can be up to 7.1 ch with higher sampling frequency and more bits per sample.

PCM is the result of DD/DTS after decoding. This can be sent over HDMI digitally to a compatible receiver. Only 2-ch PCM or encoded DD/DTS can be sent over optical/coax SPDIF. Or you can convert this to analog and send over multi-ch RCA connections.

I think this player sends multi-ch to the output set as "priority" with downmix 2-ch PCM to the other outputs.

As for what you are missing when using multi-ch, probably it is bass management. Are you sure your speaker settings in the Sony are correct? Most of the time you want to set your speakers to "small" so that bass is redirected to your sub. Use the test tone and level match also.

Your receiver probably disables bass management when set to multi-ch in. So if bass was not being redirected to your sub (speakers set to "large"), and your speakers are smallish satellites, that would explain anemic bass.
 

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