prologic 2

Discussion in 'Archived Threads 2001-2004' started by geoff dixon, Dec 2, 2001.

  1. geoff dixon

    geoff dixon Agent

    Joined:
    Sep 13, 2001
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    0
    I purchased a Onkyo 595 with the introduction of DLP2.

    I find the resultant audio matrixing a little confusing. This is in regards to the rear channels.

    I have my H.T.in a room that is fairly large. 26ft x 22ft.

    The room as open rafters {Cathederal Ceiling}

    The main rack housing has TV, Dvd, Vcr,AV receiver, and centre driver. two front drivers at left and right and sit at floor level

    Rear drivers are mounted on the rear wall which is 26ft from the main rack.

    The speaker levels have been set using SPL metering from the listening position.

    This is fine on 5.1 and DTS, the sound field is balanced.

    When playing DLP2 the rear channels are not obvious unless you sit well in front of them, the front tends to dominate, this is the same on video, cd and the old Lps.

    My understanding of DPL2 was to breath new life into old recordings, the front soundfield is fine, but where is the new life in the rear drivers? no comparsion to 5.1 Am I missing something here? I dont know.comments welcome.all drivers are made by the same Australian manufacturer and are matched.
     
  2. Tom Vodhanel

    Tom Vodhanel Cinematographer

    Joined:
    Sep 4, 1998
    Messages:
    2,215
    Likes Received:
    8
    Trophy Points:
    0
    it all depends on the original mix, try a variety of source material...esp some of the *good* surround/DPL LD/DVDs(even VHS!) in your collection. Also be sure to read the manual...there may be various settings you can adjust to suit your personal preference.

    TV
     
  3. Randy G

    Randy G Second Unit

    Joined:
    May 18, 2000
    Messages:
    460
    Likes Received:
    0
    Trophy Points:
    0
    Yeah, if I recall correctly, there is an adjustment for front to back balance...it may be the dimension control, but not sure.
     
  4. Chuck Kent

    Chuck Kent Supporting Actor

    Joined:
    May 29, 1999
    Messages:
    983
    Likes Received:
    0
    Trophy Points:
    0
    Geoff: Are you missing anything? Or expecting too much? Since DPL II is a matrixed surround vs. 5.1's discrete rear channels, in theory, you can never get rear channel action in DPL II that is possible with 5.1 DD/DTS. Even so, I have found DPL II to be MUCH better than old Pro Logic. Sometimes approaching the point that I wonder if true 5.1 is really that much better (which on most 5.1 material, it really is.)

    What can you do to help your setup?

    Since you have all of your delays and levels setup properly, and, if your Onkyo's DPL II circuitry is ok (lets assume it is), then the quality of the rears "sound" is, like TV's post above point out, the result of the encoded content present (or it's playback) in the 2 channel program.

    Dolby Pro Logic II's sound is dependent on the amount of separation between the 2 stereo channels of the programming that its decoding. So if the original program has little or no separation, or, if the equipment that's playing back the 2 channel signal decodes it with poor separation, then DPL II will not sound nearly as expansive as it could. (Specifically, the rear channels operate from the out-of-phase information in the 2 channel program (the "difference" between the left and right channels.)

    An example of what I'm saying... I use my VCRs as tuners in my system. On one VCR, DPL II sounds truely awesome. Separation that is just gigantic. But on the other one, only a few programs and commercials sound good. Everything else sounds kinda blah. So, source equipment can affect the final result we hear.

    My advice is to try experimenting with as many 2 channel programs as you can. See which ones (and which sources) are better than the others. See if your results follow what we have noted on this thread for you. I think you'll find that DPL II is still very rewarding.

    (Randy notes that DPL II has adjustments that can affect the sound. This is true for DPL II Music mode. Dolby Pro Logic II has 2 listening modes, Cinema and Music. When DPL II was developed by Jim Fosgate, he set the Cinema mode for best results with dialog driven (ie. movie) programs. But with the Music mode, he knew that decoding 2 channel music into surround would work best with some flexibility of a few parameters. The Dimension adjustment is one of those parameters. But, if my memory is correct, I don't believe that Onkyo placed the Music mode adjustments on the 595. Since Dolby doesn't require that the adjustments are manditory, for some reason Onkyo chose not to put them on-board.)
     
  5. Roger Dressler

    Roger Dressler Stunt Coordinator

    Joined:
    Jan 15, 1999
    Messages:
    187
    Likes Received:
    0
    Trophy Points:
    0
    Geoff,

    PLII somewhat favors a deader home acoustic. In our large theater, it's effects were quite subtle, but in home style rooms it is clearly obvious. Yet the theater shows the benefits of 5.1 Dolby Digital just fine.

    So I suspect your rather larger room with the high reflective ceiling may be diffusing the rear sound somewhat, thus hiding the effect of PLII. Your room may already be adding a fair degree of ambience, so adding more electronically isn't so easily noticed, whereas the discrete effects from 5.1 pop out more clearly. Is the room fairly reflective--hard floors and walls? Or is there a lot of curtains and carpets?

    I don't know where you are sitting wrt the rears, but if they are more than 120 degrees from dead ahead (as ITU describes), you might try moving them a little bit forward (towards the sides), or else consider some acoustic wall treatment. If it helps with the PLII effect, it will also help improve the detail from 5.1 that you may not realize is there.
     
  6. geoff dixon

    geoff dixon Agent

    Joined:
    Sep 13, 2001
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    0
    To all the kind people who have taken the time to answer my DLP11 problem. I say a big "thank you".

    Tom, The mix of source is noted and I will sort out the good ones, the Onkyo 595 does not have the adjustments found on the higher priced models.

    Randy G, No adjustments on the Onkyo 595

    Chuck. Thanks for your reply,the choice of material for good seperation is noted, I must say on reflection that some music does sound better. at the rear i.e. better seperation, I guess I expect the same performance from all the discs I put on, Your comments are very much welcome and thanks to you for your input.

    Roger Dressler Dolby Labs.

    Thanks Roger for the comments and advice to this DLP11 rear problem.

    The large room and your question of reflections, I live in a fairly warm climate here in Australia and my listening area has tiles with rugs, our window treatment consists of blinds not curtains.and brick walls, so I have to accept that reflective conditions exist. I have a problem in moving the rear speakers to the side due to building restrictions, and no suitable mounting area. i think your thoughts on this are correct, but to be honest 5.1 and DTS sound very good, maybe a Onkyo with DLP11 adjustments would satisfy this. or move house? Maybe!
     
  7. NathanP

    NathanP Supporting Actor

    Joined:
    Aug 13, 2001
    Messages:
    841
    Likes Received:
    0
    Trophy Points:
    0
    Hey Geoff, an old DPL tip is always : Keep your rears higher in volume then your fronts/mains
     
  8. geoff dixon

    geoff dixon Agent

    Joined:
    Sep 13, 2001
    Messages:
    27
    Likes Received:
    0
    Trophy Points:
    0
    [​IMG] [​IMG] Cheers Nathan and thanks
     

Share This Page