dts 5.1 vs dts+neo:6

Discussion in 'AV Receivers' started by WaltV, Feb 19, 2005.

  1. WaltV

    WaltV Extra

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    When I play a dts 5.1 movie in my H/K AVR330, the audio will default to dts+neo:6.

    I have a 7.1 channel layout. But I was wondering if dts+neo:6 was a matrix of all 6 channels or is it discrete 5.1 plus a matrixed 6th channel?

    I guess my underlying question is: with 5.1, the disks original encoding being discrete, will dts+neo:6 be a step up or a step down in sound quality? (And by sound quality I am thinking separation of channels, the surround experience, and sound detail).

    Sorry if I'm not so clear - I've been trying to word this post for days but I'm afraid I have a hard time describing it.

    Thanks for the input,

    Walt
     
  2. WesleyHester

    WesleyHester Stunt Coordinator

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    Your post is clear and you have a good question. I'll have to think about it though. I believe Neo:6 is for both 2-channel and 5.1-channel sources but I'll have to confirm. I've actually never have though of trying it with DTS 5.1 encoded DVDs. I do like the idea of using my rear surrounds more though. If Neo:6 does like you mentioned, I would think only the rears would be a matrix of the surround information and everything else would still be discrete. I'll have to check out my system and get on my computer at home to find out for sure though. Typically, I've only used DTS for DTS 5.1 sources and my receiver defaults to it and never Neo:6.

    Wait...
    Here is DTS's Neo:6 information from their site:

    Neo:6 PDF

    Looks like I was wrong, Neo:6 appears to be meant for enhancing 2-channel sources only. Now I'm not sure why your receiver would default to it with a true DTS 5.1 digital signal.
     
  3. Lewis Besze

    Lewis Besze Producer

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    Yeah this is a sort of "anomoly" with some receivers,as Neo was meant for 2 ch only and most hardware cannot overlay it over DTS 5.1.Having said that DTS "quietly" updated and revised Neo several times without much fanfare,don't know if the PDF above is a representative of that or only the original one.
     
  4. WesleyHester

    WesleyHester Stunt Coordinator

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    Lewis Besze, thanks for the info. I didn't even know about the revisions.
     
  5. Brad E

    Brad E Second Unit

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    This is just what H/K recievers display when playing a 5.1 format in a 7.1 setup.
    If you turn your rear speakers off, it will display only dts.
    It also displays Dolby D + Prologic (or something like that anyway) when playing a 5.1 DD track in a 7.1 setup.
     
  6. WaltV

    WaltV Extra

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    Thanks for the thoughts guys, I really appreciate it. I should add that yes, I can change the sound field to be "just" 5.1 dts when I see its gone to neo:6, then I assume its playing the discrete dts track.

    I'm still wondering: so if neo 6 is meant to send 2 channels to 6 channels, is this what is happening when the avr says neo:6? Is it using the stereo track thereby "guessing" at the surround effects? Or is it actually using the 5.1 track and just creating a rear channel?
     
  7. Lewis Besze

    Lewis Besze Producer

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    While I still don't know if your receiver actually engages Neo or just "says" it does,but when the DTS ES[Matrix] and DD EX decoding takes place, the side surrounds[and back as well] will no longer be discrete, only the front 3 channels remains as such.Neo can't do any better then that,it's clear from the PDF above.
     
  8. Brad E

    Brad E Second Unit

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    This is exactly what is happening when your reciever displays DTS+NEO6, or Dolby D+PLII.
    It's just H/K's way of telling you that the 6th channel is matrixed.

    When playing DD EX or DTS ES discreet formats, the reciever will display Dolby D EX and DTS ES.
     
  9. Lewis Besze

    Lewis Besze Producer

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    No it isn't! Only the three front channels remains discrete.
     
  10. Brad E

    Brad E Second Unit

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    I know what you are getting at Lewis, but I disagree with your statement. Just because some of the sound is diverted to the rears, doesn't make the surrounds any less discrete. To me anyway.
     
  11. FeisalK

    FeisalK Screenwriter

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    i think "discrete" here is by definition when there is an actual signal in that channel, not a signal derived from info in other channels (matrixed).
     
  12. David Judah

    David Judah Screenwriter

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    I never really thought about it when applying back surround decoding to non-EX/ES material, but it doesn't make sense to me that you lose the discrete rears because you're deriving a 6th matrixed channel.

    If you are applying DPL IIx to a discrete 5.1 soundtrack, all 4 rears aren't considered matrixed after decoding--only the 2 back surrounds are. It seems to me it's the same way with what we are talking about here with DTS+Neo 6, except only 1 additional matrixed channel is being created, instead of 2.

    DJ
     
  13. Lewis Besze

    Lewis Besze Producer

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    Roger Dressler from Dolby made this clear a while back on one of those DD/DTS threads. Maybe he'll chimes in again? To me "discrete" is any channel untouched after decoding[not counting BM]any channel that goes through a matrix type decoder can't be the same after that.
     
  14. David Judah

    David Judah Screenwriter

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    It looks like Lewis is right on this one for once :wink:. From Dolby's FAQ on DPL IIx:(emphasis mine)

    I've been using the added 6th channel for non EX/ES 5.1 sources for awhile, and to good effect for the most part. It's a credit to Dolby that it is as transparent as it is--I would have never guessed there was less "discreteness" in that configuration.

    As time goes on for me in this hobby, the more the purist approach becomes less and less important.

    DJ
     
  15. John Garcia

    John Garcia Executive Producer

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    Going back to the original question, the one reason why it would default to NEO:6 would most likely be that your receiver is setup to pass PCM rather than bitstream for DTS (typically a separate setting from DD). Check your DVD player's digital audio setup menu.
     
  16. Lewis Besze

    Lewis Besze Producer

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    Come on David, I'm right all the time you just don't know it![​IMG]Seriously though, I was in the same position as you before I've read Roger's post but it made sense once I thought of it.
     
  17. Brad E

    Brad E Second Unit

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    His reciever is not defaulting to NEO:6. It defaults to DTS+NEO:6.

    Lewis, I guess I'll have to disagree with Roger as well then. I'm not saying you guys are wrong, techincally you are correct.
    To me, a matrixed channel is one that is created from nothing. (eg: A mono source decoded with Logic7 or DPLIIx)
    IMO, there needs to be another term to describe a channel that is discrete but has some of it's sound diverted elsewhere. To lump it all in as matrixed is misleading.
     
  18. Lewis Besze

    Lewis Besze Producer

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    Except it's been estabilished that is no longer discrete,so it can't called as such, since the entire signal is going through a matrix decoder,therefore it is suiatble to call it matrix.To call it discrete or 6/7.1 as many do it here[HTF] is misleading and technically incorrect.
     
  19. Brad E

    Brad E Second Unit

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    And sends it where? In the case of the surrounds, the sound is sent exactly where it was intended to go(discrete).
    The sound from the rears is 'created' (matrix).

    And yes Logic7 will decode a mono source. Exorcist II, the Heretic has a mono track, I watched it using Logic7.
    Now in this case, you are saying that the surrounds are equally matrixed, as they would be with a 5.1 format?
    The difference is night and day.
    To paint it all with one brush defies my logic.
     
  20. David Judah

    David Judah Screenwriter

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    I know what you are saying, but once it's run through the matrix decoder it doesn't retain all that discrete information because it has to consider all 3 channels(4 for DPL IIx)as the total rear soundfield. For lack of a better word it has to make some "guesses" based on its steering logic algorithms. There's going to be some phase shifts and crosstalk(even if to a small degree)that wouldn't be present if it was completely discrete.

    There's also a distinction to make. We've been discussing a 5.1 soundtrack with no SB channel information folded into the rears. In the case of an EX/ES soundtrack it would have to "guess" to a lesser degree.

    DJ
     

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