PLII and Logic7 Go Wrong on Some Albums

Discussion in 'AV Receivers' started by amatala, Mar 19, 2004.

  1. amatala

    amatala Stunt Coordinator

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    I have a HK AVR430 Receiver connected to Mordaunt-Short Avant 906 Floorstanders (both front and surround) (plus a 905c and a 907W). I listen to my Stereo CDs on a Marantz CD5400 OSE player connected to the HK.
    I have been trying to fing my preferred Surround Algorithm to use with Stereo Music. Both PLII Music and Logic7 Music sound great, but on some recordings they can go awfully wrong.
    Two good examples are:
    1.Dream Theater - Scenes from a Memory - in the beginning of the album there is a spoken part and only parts of words (mainly vowels) are sent to the rear spakers. This is very annoying (especially because in that part you're supposed to 'Close Your eyes and begin to relax...'). Both PLII and Logic7 have the same problem, but DTS Neo:6 works perfectly on this one.
    2.Alan Parsons - I Robot - During the long fade-in in the beginning of the album, the volume in the rear speakers is constantly varying and sometimes the sound cuts completely for very short moments. Again, this happens for both PLII and Logic7, but not for Neo:6.

    Now I know these algorithms can sometimes give strange results, but the question is: what could be done in order to reduce or eliminate these unpleasant effects? In there any setting that could help?
    Any suggestion would be appreciated...

    Thanks!
     
  2. Roger Dressler

    Roger Dressler Stunt Coordinator

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    Adrian wrote:
    >>Alan Parsons - I Robot - During the long fade-in in the beginning of the album, the volume in the rear speakers is constantly varying and sometimes the sound cuts completely for very short moments. Again, this happens for both PLII and Logic7, but not for Neo:6.
     
  3. amatala

    amatala Stunt Coordinator

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    Hello Roger,

    Thanks for the reply. I will come back with more details later today, I will try to write down some time indexes.
    For I Robot, PLII performed better than Logic7, but it still didn't seem 100% right. I've listened to it several times, with my ear very close to the left surround speaker (I am using a 5.1 config, no rear back speakers).
    I've reproduced the behaviour on both my HK430/MS config and on a HK3550/JBL, they both produce the same result.
    Maybe I'm just being overpretentious and this kind of discrepancies are supposed to happen with all surround algorithms - in this case I'll try to live with it.
    On the other hand, if you could find a copy of Dream Theater's Scenes from a Memory, try listening to the first minute or so. The rear speakers seem to be kicking in and out in the middle of the words, producing very annoying effects. PLII seems to think that the deeper inflexions of the voice should go in the surrounds...

    Thanks!
     
  4. Roger Dressler

    Roger Dressler Stunt Coordinator

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    Adrian,

    >>I've listened to it several times, with my ear very close to the left surround speaker
     
  5. amatala

    amatala Stunt Coordinator

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    Roger,

    I've reduced the volume on my surrounds a little bit and listened again to the albums from a central location.
    Indeed, with this setting no strange things could be heard on I Robot with PLII. Logic7 still seems to struggle (the interruptions in the surrounds are much more obvious), but I don't use Logic7 much so it's not very important.
    On the Dream Theater album, the voice cuts can still be heared. What I don't understand is why PLII tries to send the voice to the surrounds - normally voice should stay in front and only echoes send to back (the way Neo:6 does). You should listen to this sometime, only for fun [​IMG] .

    Anyway, it is quite clear that the most advanced and spectacular result is obtained with PLII. Neo:6 sounds good on certain albums because it is closer to the original Stereo sound, but I prefer PLII because it creates full-range surround channels (after all, I have floorstanders for my surrounds and I do want to use them fully).

    Thanks for all your good advice!
     
  6. Roger Dressler

    Roger Dressler Stunt Coordinator

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    Adrian,

    Thanks for the further report. At least it sounds like there's no fault with your PLII system--which is something I was wondering originally.

    >>On the Dream Theater album, the voice cuts can still be heared. What I don't understand is why PLII tries to send the voice to the surrounds - normally voice should stay in front and only echoes send to back (the way Neo:6 does). You should listen to this sometime, only for fun.
     
  7. amatala

    amatala Stunt Coordinator

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    Roger,

    The Stereo effect PLII puts in the surrounds is indeed much richer than the one Neo:6 does. That's one of the reasons I prefer PLII.

    >>At least it sounds like there's no fault with your PLII >>system

    I am no Pro in this domain, but I do think my PLII behaves quite well. I do not experience any sound muffling (like others reported on this forum), on the contrary: the PLII sound gives a more open and wider soundstage than the one Stereo does, without any loss in sound clarity. Maybe some Stereo purists will argue, but I do think PLII sounds better than Stereo in all possible ways.

    >>Our previous decoder, Pro Logic, derived only one >>surround signal, so the logic decoder starts off by >>extracting L-R, with the L and R having equal weighting. >>Any vocals, dialog, effects mixed perfectly to the Center >>(L=R) will be automatically nulled from the surround >>output. Leakage will be essentially zero even if the >>matrix decoder is not hard steered to the Center by a >>strong vocal.

    I am also very familiar with ProLogic (before my current HK receiver, I used a Panasonic amplifier with ProLogic for all my music. There was indeed no voice leakage in the surrounds with ProLogic, but the overall result was cleary inferior to the one PLII produces.

    >>I suspect what is happening in Dream Theater is that the >>vocals are at a similar loudness as other parts of the >>music, so the PLII decoder cannot perfectly grab onto it >>to isolate it from the surrounds.

    Actually there is no music in that part of the album: the album starts with clock ticking sounds and a narrating voice. Only the deeper sounds of the voice are being sent to the surrounds (some parts of the words) and since there are no other sounds to cover it, the surround cuts are quite obvious. Music progresivelly fades in and the voice slowly fades out and things become normal after the first minute.
    Anyway, I am sure that situations like this one are quite rare. I've listened to several 'difficult' albums through PLII and the results were almost always excellent. I was very impressed by the way PLII handled Yes' album 'Close to the Edge' (one of my all time favorites) - the result was trully amazing!

    Thanks Again!
     
  8. Roger Dressler

    Roger Dressler Stunt Coordinator

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    Adrian,

    >>Only the deeper sounds of the voice are being sent to the surrounds (some parts of the words) and since there are no other sounds to cover it, the surround cuts are quite obvious. Music progresivelly fades in and the voice slowly fades out and things become normal after the first minute.
     

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