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5 channel sound from CATV??


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#1 of 8 Mark--M

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Posted June 16 2005 - 02:13 PM

I noticed that a friends HT system has 5 seperate channels playing while watching cable. He also tells me that he does NOT have digital cable?

So how is this working? Makes no sense, most recievers just have 2-ch audio inputs and digital inputs for multichannel signals.

What am I missing here? How is he doing this?

#2 of 8 Robt_Moore

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Posted June 16 2005 - 02:52 PM

Dolby Pro Logic II.

#3 of 8 John S

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Posted June 17 2005 - 03:18 AM

5 channel stereo, DPLII, DPLIIx, DTS NEO:6, LOGIC 7, Denon Widescreen, probably a few others too. Are all modes that will achieve this from 2 channel sources.

#4 of 8 Mark--M

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Posted June 17 2005 - 05:54 AM

So your thinking its just a 2 ch source thats being processed and played through the rest of the speakers?

I find this hard to beleive. Things were clearly seperated just like watching a DVD. Voices would be on the center and center only, music would be on serveral speakers, applause in the rears only, etc

My reciever has a few options for just sending part of a 2ch signal over the rears to creat a surround effect, but this is completely different. I dont know? Posted Image

#5 of 8 John S

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Posted June 17 2005 - 07:28 AM

Well, these newer modes are pretty darn good at it, enough to fool you for sure....

I'm pretty sure DD 5.1 is is not possible without digital cable at a minimum.

So good in fact, I hardly bother with AC3(DD 5.1) anymore when watching my laserdiscs. DPLII, DST NEO:6, and Denon 7.1 Widescreen mode are all amazing off the 2 channel with the player. I mean even if I forget to set it back to the digital output after viewing a laserdisc with no digital sound. (Straight 2 channel analog Pro-logic and/or Stereo)

#6 of 8 ScottCHI

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Posted June 17 2005 - 09:22 AM

most digital cable broadcasts are not DD5.1, anyway; they're just DD2.0. very few cable channels are actually broadcast as 5.1. only 1 or 2 of my HBOs and 1 or 2 of my showtimes are capable of DD5.1 at any one time. apparently, there is a bandwidth issue. i'm not sure how satellite dish broadcasts work regarding this.

how is your friend's cable box's audio connected? it'd have to be a digital audio connection (optical or coax) to pass a true 5.1 signal to his receiver. if he has no digi connection, then he definitely hasn't got 5.1 cable audio. if he does have a digi connection, then there should be some way to tell (indicator on receiver's display) that that is indeed what kind of signal is being decoded by the receiver.

my cable box is connected via a digi coax connection and my receiver, which auto-detects a DD5.1 signal and plays it as 5.1, is setup to play DD2.0 as DPLII.

Quote:
My reciever has a few options for just sending part of a 2ch signal over the rears to creat a surround effect, but this is completely different. I dont know?
will your receiver not do Dolby ProLogic II?
"All men are frauds. The only difference between them is that some admit it. I myself deny it."

#7 of 8 Mark--M

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Posted June 19 2005 - 03:27 PM

My reciever has Pro logic, but not sure if its I or II. Is there a big difference between the two?

So does this processing work perfectly on all 2ch recordings or are some recordings designed with this in mind?

Pro logic on my system is nothing like his. On mine the center is on most of the time, and the fronts seem to be getting the same signal for the most part but at a much lower volume. His is much more clearly seperated. And certain effects are clearly noticable on his surrounds, my surrounds just seem to be getting the same signals as the fronts, but at a lower level still.

Is this because of the source or because it was Pro logic I instead of II maybe?

#8 of 8 FeisalK

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Posted June 19 2005 - 03:50 PM

Mark,

*huge* difference between PL and PLII. Check out this article at Secrets

the PLII intro article (linked from above article) states:
Quote:
Dolby Pro Logic II is an improved, more intelligent matrix decoder. So improved is its decoding, that it succeeds where Pro Logic performed poorly, i.e., playback of non-encoded material such as conventional 2-channel music. That's not to say it is a music-only application, but it certainly makes for a new and wide appeal. Conventional Pro Logic decoding lends itself perfectly to motion picture soundtracks. The surround channel is predominantly diffuse ambiance, and the bulk of the soundtrack is focused to coincide with the visual front and center. It is this "center heaviness" that many music enthusiasts find objectionable with 2 channel music through Pro Logic.

In Pro Logic II, the most significant technical difference from Pro Logic is that it incorporates a "feed back" design, in that the directional enhancements are applied back to the input of the active matrix.

my PLII is on by default on my TV input and almost all of the time when listening to music CDs (I am not a stereo purist). On some music CDs (like Queen's ANATO, for example) PLII can be quite stunning
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