What happens when you listen to a DD5.1 soundtrack on a 7.1 system?

Discussion in 'Archived Threads 2001-2004' started by Joseph_Mikhail, Apr 22, 2002.

  1. Joseph_Mikhail

    Joseph_Mikhail Stunt Coordinator

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    Does anything come out of the rear surround speakers? Or do you have to use PLII with a two channel source?
     
  2. Harold_C

    Harold_C Stunt Coordinator

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    Yes, something will come out of the center back speakers.

    A Dolby Surround EX disc is NOT a 6.1 channel recording. It is a 5.1 channel recording with a center back signal matrix-encoded into the existing surround channels. The decoder (either Dolby Surround EX or the receiver's automatic decoder) extracts a center back channel using a process that is essentially identical to the way Dolby Pro Logic extracts a center channel from a stereo recording.

    When you play a 5.1 channel disc, either of these decoders will still extract a center back channel signal -- just like Dolby Pro Logic derives a center channel signal from a stereo CD or FM broadcast.

    Dolby's Surround EX decoder tends to put a little too much in the center back channel. Some of the auomatic proprietary decoders reportedly do a better job of spreading the surround signal around to all of the surround speakers by using algorithms like the wide mode of Pro Logic II.
     
  3. Keith Mickunas

    Keith Mickunas Cinematographer

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    It depends on the receiver and the settings you are using. If you have it in a straight 5.1 mode, then nothing will come out of the rear center. However I think most processors can still pull a rear channel out of a regular 5.1 soundtrack without much trouble. They should have some sort of matrixed mode that will do that processing. DD5.1 and 7.1 soundtracks have nothing to do with Dolb Pro-Logic 2. DPL2 is also meant to take a stereo signal to 5 channel, and again it would be up to the receiver to pull out a rear center for that mode.
     
  4. Joseph_Mikhail

    Joseph_Mikhail Stunt Coordinator

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    What if your receiver doesn't do DD EX. I have a HK 520 and have been thinking about upgrading to 7.1. I guess I can use DTS ES or Logic 7 in 7.1 mode.
     
  5. Kevin C Brown

    Kevin C Brown Producer

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    Joseph- Keith is correct. But I'll add a little more. Logic 7 will also fill the rear speaker(s). And modes like CES for Outlaw's new pre/pro, and xS for Rotel's new one.

    But, I do believe that HK's implementation of Logic 7 can only be used with 2 channel sources. I think there was a big thread about this not too long ago.

    It is *possible* to apply DD EX decoding to a DD disc, or DTS-ES decoding to a DTS disc. But if there is a lot of common, in-phase material in the 2 surround channels, that info is removed and sent to the rear(s).

    That's why, in general, it's best to decode "std" DD/DTS discs with a mode specifically meant to "expand" 5.1 sources to 6.1/7.1.

    Save DD EX and DTS-ES for disc specifically encoded that way.
     
  6. Joseph_Mikhail

    Joseph_Mikhail Stunt Coordinator

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  7. Harold_C

    Harold_C Stunt Coordinator

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  8. Kevin C Brown

    Kevin C Brown Producer

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    HC- I suppose it would depend on how good the original mastering was. I think that in an *ideal* world, a disc specifically mastered to DD EX/DTS-ES "standards", *should* sound better than using a generic matrix expansion mode on a 6.1/7.1 system. But of course, ymmv... [​IMG]
     
  9. Wes

    Wes Screenwriter

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  10. Harold_C

    Harold_C Stunt Coordinator

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  11. Wes

    Wes Screenwriter

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  12. Doug Smith

    Doug Smith Second Unit

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    My question is what are the best 6.1/7.1 "generic" receivers out there. Any ideas?
     
  13. AaronMK

    AaronMK Supporting Actor

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    What if they want a sound to come out of all three of the back channels?

    Also, do most 7.1 receivers allow you to feed the back channels of 5.1 mixes into all four back speakers without using EX/ES decoding (SL out of two speakers and SR out of two speakers) and is this desireable?
     
  14. MatthewJ S

    MatthewJ S Supporting Actor

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    Aaron, good question ,however from what I have discovered , the answer is NO...While Denon has 2 sets of surrounds and another set for surround back, you would have to employ 5 surrounds to use 4 as 5.1 (out of 2 sets of surrounds) while also allowing for 6.1 ...for so called 7.1 with denon you would need 6 surround speakers to do what you are refering to...WAF?!!!!

    There is one rcvr that can do (easily) what you are asking

    B&K's AVR307......
     
  15. GregK

    GregK Screenwriter

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  16. Kevin C Brown

    Kevin C Brown Producer

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    Aaron- And modes like CES by Outlaw and xS by Rotel are *designed* to spread the 2 surround channels of DD or DTS (or even DD 2.0/DPL/2 channel stereo however encoded) through up to 4 (surround/rear) channels. Most receivers (now) do have equivalent modes.
     

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