Axiom Home Page Forums General Discussion Home Theater Question about PCM lossless and optical cable

Hi!

I recently added a vp100 v2 to my pair of M3 (next purchase will be pair of QS4 next year or sooner), and I started this week to enjoy better overall sound from movies.

I just discovered that optical cables can't handle the bandwith of PCM lossless 5.1 soundtrack from my PS3 and hd-dvd player. Only hdmi cables can do the job (there's lot of information about that on the web). And my receiver do not have hdmi connector for sound. I know that the logical solution would be to buy a new receiver for optimal results, but I want your opinion/advice on this.

Based on my actual configuration, it is better to:
1- Go with PCM lossless sound on 2 channels and let the receiver do processing with Dolby Pro Logic?
OR
2- Go with the regular Dolby Digital 5.1?

Actually in 2.1, the sound seems better with PCM processed with Dolby Pro Logic. On the other hand, when I'll get surround speakers, I think that the Dolby Digital will do a better job for surround sound.

Is that a logical thought?

Thanks for your opinion!

PS: There's no bandwith problem with optical cable for Dolby TrueHD and DTS-HD soundtracks. Just too bad that Black Hawk Down blu ray only have high def soundtrack in PCM lossless.

Patrick

I didn't think the PS3 downmixed and matrixed the multi-channel PCM when being output over the optical link. But if you're hearing clear dialog (the center channel), then it must at least downmix.

You're right, a new receiver would be the "best" solution, but until I got mine I was very happy with the optical outputting Dolby Digital or DTS. Honestly, I was a little disappointed with how little difference I heard after the upgrade. But getting the two extra surround channels with 7.1 which prompted me to buy the QS8s, was an ear opening experience.

While technically, there may be enough bandwidth on a S/PDIF link for Dolby TrueHD or DTS-HD Master Audio, that is not what you get. When picking one of the lossless formats, the PS3 selects the "core" lossy portion of that track and sends that to the optical port.

The way you should have your PS3 configured is for optical output with bitstream. Then pick the highest quality audio track on the disc which is not PCM. If a Blu-ray has both Dolby Digital 5.1 and DTS-HD Master Audio, pick the later. The Core of MA is a 1.5 Mbps DTS track, which will top Dolby's lossy offering.

Wait, you can send True-HD over optical cables? But that's in 'unpacked' mode right? I don't think my Denon would know what to do with bitstreamed True-HD since it came out before those formats did. I wonder what it would do with it?

No, what Chris indicated was that the lossy content(which again, may not be audibly distinguishable)would be transmitted over the optical or coaxial digital connection.

Incidentally, the term "lossless" has no application to a PCM track, since PCM on CDs or other discs has no data compression, lossy or lossless.

What I was trying to say without saying it, is that quality optical and coax (for reference see the telco world where 45 Mbps is routinely transmitted over RG-6 coax) are more than capable of handing the bandwidth required for multichannel, lossless audio. The truth is the studios did not want to update the S/PDIF specification, an unencrypted interface, to carry the new codecs. So it was mandated that they only be sent over HDMI.

So yeah, any player will only send the lossy "core" of the lossless codecs to the optical interface.

Interesting information about that decision.

And thx a lot for your help.
My PS3 was in fact configured for bitstream at start. But because of Black Hawk Down movie soundtracks, I was trying different ways to get the better of this and from my actual equipment.

Got over 50 high def movies, but only 2 of them have PCM 5.1 soundtrack. At least they also have DD 5.1 !

Those wiley ol studio's and their tricks. I wonder just how long it's going to take them to render 1080p 'yesterdays news' and double or triple the resolution? I mean after all house hold tv's went a whopping... what, 50 years? Before they finally upped standard resolution first to 1080i and now 1080p. But my guess is in todays ever changing digital world 1080p isn't going to stick around as 'King of the Hill' for that long. I give it a good ten year run max before 'Blu-squared-Ray takes over, or something similar.

Can you imagine the day our grandchild says, "grampa what's this"? And we say, "oh that's a Blu-Ray disc. We used to watch movies from these". And they giggle and say, "wow, you really are old grampa".

That day is coming, believe it or not.

It could also come to a point where everything collapses, and it will be a long time before another civilization surpasses the technology that we take for granted, but I'm hoping it goes the way you're saying.

Oh I have no doubt about that at all. I'm hoping our grandchildren don't see it, but rest assured we will not be the last civilization to rule this world. The dinosaurs had a much longer run then we'll ever enjoy. We simply gobble up way too much of the earths resources to make it millions of years. Our species have had a good foothold as the top of the food chain for less than 35,000 years and already we're nearly at the breaking point as far as being able to sustain ourselves... how are we supposed to make it another 15 or 20 million years?

And the earth is still young. It has enough years left in her to see at least another 4 or 5 civilizations rise and fall before it's all over. We will not be here when the sun explodes. There's not a doubt in my mind about that. If we live to see the next ice age, it'll do us in almost assuredly. Or a meteor. Nuclear war. AIDS. Take your pick.

By reaching out to the stars......

No I don't mean space exploration and habitation, I mean the other stars. Tom Cruise says he is the only one who can save us.

Wait.... We're doooomed!