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Plasma lag

Discussion in 'Plasma TVs' started by Spanjab, Jun 4, 2003.

  1. Spanjab

    Spanjab
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    Hi all,

    I seem to remember reading somewhere about the fact that sometimes plasma TV's images can lag a little behind the picture. It is a subtle lag but on mine it is often clearly visable and once noticed it is really distracting.

    Is there a way to correct this lag by perhaps delaying the sound getting to the amp?

    Spanjab
     
  2. Kazuya Mishima

    Kazuya Mishima
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    Some of the forum users use an amp which will introduce an adjustable sound delay - for example a Denon 3803.

    If you search the forum for "lip sync" that will give you a few ideas.
     
  3. briandzo

    briandzo
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    you need to clarify is this a Video or Audio Problem you require help with
     
  4. IanM

    IanM
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    It's a video problem with an audio solution.

    The delay is due to the deinterlacing and video processing performed by the plasma. The only way to "correct" it is to delay the audio by a similar amount, as Kazuya suggests.

    Having said this, I'm not sure how much the size of the screen is a factor. The reason I wonder is because different channels on Sky seem to have different delays. This seems to indicate that at least some of the delay is introduced by the broadcasters (unless some channels require more processing by the plasma than others, which is unlikely). I never noticed this with a smaller screen, so maybe the sheer size of plasma screens means that you notice the lip sync problems more.

    Does anyone know if this is the case, or am I just talking a load of gonads?

    Cheers,
    Ian.
     
  5. miniman

    miniman
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    Spanjab what plasma do you have?
    Is your problem mostly noticable on peoples faces and does it leave a ghosting effect?
     
  6. MarkE19

    MarkE19
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    Lip-sync is more noticeable on larger displays.
    I've got a multi-effect unit that has sterio delay and have programmed it in 20ms increments from 20 - 300ms. This covers all the problems for me.
    These units can be bought from musical instrument shops and cost from around £80 up. Try www.turnkey.co.uk

    Mark.
     
  7. PVR

    PVR
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    I solved it using the Behringer unit bought from Joe, which has fully programmable audio delays. I have set a number of pre-set of from 80 Ms to 160 Ms so every different delay channel is covered. However, this unit only works for the Sky two channel stereo connection, not Sky + or so as the delay unit is not a digital one.

    Regards,

    PVR
     
  8. briandzo

    briandzo
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    Spanjab

    Due to your post being a tad vague.
    Equipment and description wise.

    Have you got DNR (digital noise reduction) turned on.
    If so try disabling this option.
     
  9. edz

    edz
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    Hmm

    this ties in with something I've noticed in a jumping off at right angles, rambling kind of way ....

    I capture shows from Sky to my ATI card in a pc, when I check the recordings, even if live they have a very slight almost non perceptable delay, (this is the same on VHS so its not the equipment), by the time I've converted mpeg audio to AC3 etc its off by a whopping 62 ms which I have to remember to convert before making a DVD.

    Now, in my usual wobbling around the point kind of way, what I mean is this. Could it be in both cases: plasma sets and capturing that delays that are being exacerbated by equipment processing are ALREADY present when the shows are broadcast.

    I noticed a few times in Enterprise on Sky One that the sync is out, sometimes by a bit but sometimes perceptably off.

    As I said, an observation, in any case the audio delay (either realtime for you plasma guys ... jealous, me ?.... or using ac3delay for us PC DVD makers seems to fix it but since Sky are now selling plasmas in the sky guide it would be really nice if they'd check sound sync on them once in a while.


    Anyway, rambling post over and out.


    Cheers

    Edz
     
  10. vonhosen

    vonhosen
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    I use a Vigatec WAVE which will give you an adjustable audio delay for AC3 & DTS bitstream as well as stereo. It's an expensive solution though.

    Cheaper to get a new Denon 3803 Amp ;)


    In the capturing of video in the PC World audio out of sync can often be down to dropped frames during capture. (This can be down to either the hardware capturing or quality of original transmission)
     
  11. Spanjab

    Spanjab
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    Hi there,

    Sorry about being vague! My screen is a Panasonic 42 inch plasma (5) with a Sony 930 amp. I don't have any DNR activated, surely if this was on and delaying the noise while it processed it then the sounds would lag behind the picture, not the picture behind the sound.

    I have been thinking about a new amp anyway, I'll investigate this Denon, do any others offer the delay option?

    Spanjab
     
  12. MarkE19

    MarkE19
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    edz,
    Yes, Sky (and others) do transmit programmes that are out of sync. It just gets noticeable on larger (ie plasma) screens and then with the added processing does make it worse.
    Since starting transmittions in digital this has got a lot worse as the TV companies have sync problems due to processing before it is even transmitted.

    Spanjab,
    The 3803 is the only receiver (AFAIK) in its price range (£900) that has a master delay. Once you get into the £1500+ range then this feature becomes more common.

    Mark.
     

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