A Question about DIY 6.1

Discussion in 'Archived Threads 2001-2004' started by Richard Burzynski, Jan 4, 2002.

  1. Richard Burzynski

    Richard Burzynski Second Unit

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    I know many people on this board have tried and use a DIY solution for 6.1. Assuming you have a 5.1 Receiver/Prepro, you basically can do this 2 ways: (1) Buy a dedicated rear center channel device like the ones from Parasound or Smart Devices; or (2) Just use a DPL receiver/prepro to do the processing for you.

    I know that you can derive rear center channel information by using discrete 5.1 sources like DD or DTS. My question is, can I derive some psuedo rear center channel information from DPL sources like Cable TV or a VHS movie?

    You guys that use/d an old DPL receiver for the rear center, did you get rear center signal if source material was DPL?

    Thanks.

    Rich B.
     
  2. Andrew Beck

    Andrew Beck Stunt Coordinator

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    My understanding is that since the rears in DPL aren't discrete, if you ran them into a second DPL decoder to get a center channel, everything would come from that center channel. Just like if you watch a mono movie and everything comes out of the center.
     
  3. Kevin C Brown

    Kevin C Brown Producer

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    What you need, is a DPL receiver/pre-pro/processor that has a "3 channel stereo" -like mode.

    Not "3 channel Dolby Pro Logic", but 3 channel stereo.

    No DPL decoding on the rears, just "averages" the two existing surround L + R channels into the newly created rear channel(s).

    I have the Shure HTS-5300 Dolby Pro Logic processor that has this mode.

    Now, you can *also* try other modes on your DPL receiver/pre-pro/processor other than "std" DPL . All you're trying to do is to get a mode that will leave some of that in-phase/mono material to remain in the surrounds.
     
  4. derek

    derek Second Unit

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    The 3 channel stereo would be nice if you have it...but if not leave the rear processor in 'stereo' mode...simulating a normal Pro-Logic surround array (right/left surrounds receiving same mono signal.)
     
  5. Richard Burzynski

    Richard Burzynski Second Unit

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    Thanks for the replies guys. I should be more specific. From reading several DIY 6.1 threads I see there are 2 ways to "create" the rear center.

    (1) Using an external DPL processor to process all surround information, meaning right rear, left rear, and rear center.

    (2) Using an external DPL processor to create a rear center ONLY, while allowing "original" preamp to process the right and left rears.

    I am leaning towards method #2. I assume this will yield a rear center which is always on (along with side surrounds) when source material is DPL due to mono surround signal?

    Thanks.

    Rich B.
     
  6. Kevin C Brown

    Kevin C Brown Producer

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    Richard- You have it. [​IMG]
    Which ever way you choose, DPL processing in the rear uses the two L + R surround channels as the inputs, and you choose the outputs you want, 1) front (which is back) L, C, R, or, 2) just the rear center (fron center).
    For #2, you have to use Y cables before the DPL processor. 1/2 of each side of the Y (L, R) goes to your amps for the original L + R surround channels, and the other 1/2 goes into the DPL processor. And then just like you suggest, you only use the center output from the processor for the new rear channel.
    I tried it that way for a very short time. 2 reasons why I switched back: 1) a lot more difficult to properly set the level of the rear center speaker, and 2) because I have a choice of DPL in my processor for (THX) Surround EX/DTS-ES material, and a "3 channel stereo" mode for std DD/DTS discs.
    You might try it both ways, and see what you think sounds better.
     
  7. GregK

    GregK Screenwriter

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    I also first had my home brew set-up like your #2

    method, and like Kevin, I switched over to "true"

    three channel decoding (meaning I now extract

    the center out of the left and right surrounds)

    because of the reasons he stated, along with the

    fact that the sound field just seemed more defined

    with the center rear info only coming from the

    rear.

    As for straight DPL decoding ala EX, for myself, I don't

    mind mono surrounds being in the rears only. My left and

    right surround speakers are closer to being 'side channel'

    speakers in my given set-up. This makes any split surround

    activity stand out better, while the center rear speakers

    still provide the better sense of "envelopment" that rear

    speaker placement brings. Of course mono surrounds (DPL or

    DD 4.0) have no split surround activity, so they can stay

    in the back and provide superior ambiance in the rears as

    far as I'm concerned. ..However on occasion when I'm

    watching a DPL or 4.0 movie with little surround activity,

    and if I am listening at a lower volume level, I will

    sometimes turn off the DPL decoding in the DPL back channel

    "EX" decoder. ..Then the mono surrounds are routed just to

    the left and right surround speakers, and EX decoding is

    effectively bypassed. But most of the time, I tend to keep

    my system in the typical "EX" mode. My H.T. system is also

    calibrated for EX as well.

    Btw: Has anyone with a home brew EX system listened to

    DPL-2 ala "EX" style???
     
  8. Richard Burzynski

    Richard Burzynski Second Unit

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    Thanks guys. I will experiment after it's hooked up. However, my current rear center processor only has straight DPL, no 3 channel stereo or Dolby3, at least I don't think it does. I'll be using the Sony 800 LD(AC3RF) / DD processor.

    Rich B.
     
  9. Kevin C Brown

    Kevin C Brown Producer

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    Richard- That's the Sony SDP-E800?
    You will have to see if you like it or not. I tried one for a while for the same use, but it is quite "noisy". Puts out a lot of hisssssss... [​IMG]
     
  10. Richard Burzynski

    Richard Burzynski Second Unit

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    Uh oh.

    That's the one - I forgot the actual model #.

    I read mixed reviews on this piece, many like yours stating that it's noisy, others, however, thought it was quite good for the $.

    I'm not going out of my way to buy one - it's the only DPL piece that's currently in my stable, therefore I "have" to at least give it a try.

    We'll see - soon.

    Rich B.

    (fingers crossed)
     
  11. Richard Burzynski

    Richard Burzynski Second Unit

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    Nothing like replying to your own post. [​IMG]
    In the event my Sony 800 stinks up the joint, what DPL processor (receiver) do you guys recommend I get, $ being a factor, of course.
    Rich B.
     
  12. Kevin C Brown

    Kevin C Brown Producer

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    Richard- I use a Shure HTS-5300.
    But there is also the Sony SDP (?) 777ES, Yamaha DSR-70 Pro, and DSR-100 Pro, Pioneer SP-91d, and others.
    If you're interested, just so happens I have one of the Sony's right now. [​IMG] ES Dolby Pro Logic decoder. Also has Hall, Stadium, etc, DSP fields. Went for something like $800 new in the early 90's. Genuine wood side panels (can be removed). I have the box and manual and remote. I don't want much for it if the original list scares you...
    I also have a review on it from Audio (or Stereo Review, can't remember which) back then. Very highly reviewed. I'd include that.
    I decided to keep the Shure, just because it's kind of bizarre looking. [​IMG]
    Oh, the 777es *is* much quieter than the E800. I.e., like a "normal" component: silent. [​IMG]
     

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