Do i need 7 speaker for DTS 6.1?

Discussion in 'Beginners, General Questions' started by Tom Martin, Apr 24, 2004.

  1. Tom Martin

    Tom Martin Stunt Coordinator

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    i'm not sure how DTS 6.1 works, but does it mean i need a REAR CENTER speaker?
     
  2. GeorgeAB

    GeorgeAB Second Unit

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    Tom,

    You'll need: LF, C, RF, LSur, RSur, Back, and a sub if the fronts are not full-range. This is minumum. If the room is large, two back speakers may work best.

    Best regards and beautiful pictures,
    G. Alan Brown

    "Advancing the art and science of electronic imaging"
     
  3. ChrisWiggles

    ChrisWiggles Producer

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    You don't *need* 6.1, but if you do so, you can add a single rear back, though it is recommended you use two rear backs for a 7.1 setup, even if you have to wire them together off a 6.1 receiver. They will be in mono, but it eliminates the reversal effect.
     
  4. Tom Martin

    Tom Martin Stunt Coordinator

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    ok, i have a DTS decoder but i only have the 5.1 speaker setup. what happens when you use that to play 6.1?
     
  5. Nick.H

    Nick.H Stunt Coordinator

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    It just emulates the sound through the rest of the speakers. Nothing serious, as far as I know there are not many 6.1 DTS dvd's out.

    Tho I do have 6.1 and think it gives it a more surround feel, I would not go for 7.1.

    Got 6.1 have the front and rear matching... 3 and 3
     
  6. ChrisWiggles

    ChrisWiggles Producer

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    Tom: I am unclear as to your setup/situation. REgardless, all the DD and DTS systems that can do 6.1 or beyond are totally backwards compatible. I've explained this very thoroughly in some past threads, I'll see if I can dig some links up for you, but basically, no matter what, on the disc is a full 5.1 mix. DTS-ES matrix and DD-EX disks are *NOT* actually 6.1. Without any processing applied, which would occur with older processors that lack EX-processing, it's a regular 5.1 disk. This would also happen if you only have a 5.1 speaker setup, just make sure you set your rear back speaker to "OFF", since you have none, and everything will stay in full 5.1 as it is on the disc.

    DTS-ES discrete is a little more complicated, because there IS a 6th channel on the disc discretely, however, to stay compatible with regular 5.1-only DTS decoders, that information is also contained in the normal surrounds. So no matter what, a 5.1 setup playing EX/ES or ES-discrete discs should be totally fine.
     
  7. ChrisWiggles

    ChrisWiggles Producer

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  8. Sean Conklin

    Sean Conklin Screenwriter

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    I play dts ES with a 5.1 receiver and it sounds just fine, the surrounds are discreet and sounds excellent. I think Chris is right, there is normal dts 5.1 information on the ES format and the 6th channel info is just a bonus as its discreet and does nothing to hinder the discreet sound if you don't have 6.1 capability or a rear center.
     
  9. GeorgeAB

    GeorgeAB Second Unit

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    Tom,

    All 6.1 and 7.1 movie formats on DVD still derive the back channel(s) from a matrix of the original film's left and right surround tracks. If you decide to add a back channel speaker, do NOT use a duplicate of your center channel speaker unless it also is designed like your front L&R speakers. Many center channel speakers are specifically designed for the center-front only. The functions of the center and back channel are vastly different and the signal content sent to those two channels is also dramatically different.

    Choosing a back channel speaker depends as much on the room and where you sit in the room as anything else. It would be much better to match what you are using for the surrounds, than the center. There are so many variables that determine what is best, no one can tell you what would be appropriate without a lot more information than you have provided thus far.

    Best regards and beautiful pictures,
    G. Alan Brown

    "Advancing the art and science of electronic imaging"
     
  10. ChrisWiggles

    ChrisWiggles Producer

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    Correction: to be clear, as I alluded to in my post, DTS-ES discrete does indeed include a discrete 6th channel rider for decoders capable of receiving and decoding that information. However, as is much more thoroughly explained in the thread I linked, that information is also included in the regular 5.1 mix, very much the same way non-discrete ES, and EX titles are, to keep things fully backward compatible, and also compatible with ES/EX matrix processing that does not have the discrete 6.1 capability.

    7.1 variants can either be just 6.1 implemented with the recommended dual rear speakers, or the same speaker implementation but with added processing around the rear for 4 independant surround channels.

    I'm with George in recommending that you try to match the other surrounds with your rears, but I disagree with the notion that a front center channel is "specifically designed for the center-front only," and somehow not designed similarly to your main L/R speakers. While most horizontal center can suffer from design problems because of the popularity of horizontally arranged speakers, unless your center is woefully poorly designed, or horribly matched, it should ideally be identical to your mains. And so should all your surrounds. Thus it wouldn't be that big a deal to use a center for your rear back, and it may, because it's horizontally oriented, minimize the reversal effect that using two rear backs is recommended for.
     
  11. GeorgeAB

    GeorgeAB Second Unit

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    Reality is, unfortunately, many center channel speakers are not designed correctly, even for center channel use. Many are designed specifically for center channel and done well. These can be more expensive than necessary in a back channel application.

    Unless the film industry has changed their methods in recent months, they still derive the back channel from the left and right surround tracks on the 5.1 master. DTS has chosen to encode that information to a discrete 6th channel. It does not benefit from the superior separation theoretically possible from the original discrete mastering of digital 5.1.

    Even with 5.1 there are compromises made on many films. A large portion of movies made today still use mono for surround information. They save production costs and time that way.

    Best regards and beautiful pictures,
    G. Alan Brown, President
    CinemaQuest, Inc.

    "Advancing the art and science of electronic imaging"
     
  12. ChrisWiggles

    ChrisWiggles Producer

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    Actually, I'm pretty certain that when mixing EX/ES titles, the masters are fully discrete, (just as was done in pro-logic days: then matrixed into stereo), then matrixed into a 5.1 format, or 6.1 for discrete ES.
     

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