VT50 Coloured Pixel Noise/Snow

Discussion in 'Plasma TVs Forum' started by Roon1, Aug 5, 2012.

  1. Roon1

    Roon1
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    Hi all,

    I have just received a replacement VT50 as the first one had a dead pixel, the dealer swapped over within days which was superb.

    Obviously I have spent the day scrutinising the TV to make sure it is perfect and have noticed that there is a lot of coloured flashing pixels perhaps best described as noise or snow which are over the blackest parts of the picture and are particularly visible from a black screen/title credits.

    These are visible on all sources SD & HD, freesat, sky and on blu ray too. I have never noticed these before on my old VT20 or the previous VT50 just replaced.

    I am amazed at how bad his appears to be, you cannot see it from viewing distance but if you stand closer to the screen you can see it clearly.

    Question is, is this normal, if not what is it? Does anyone else have it or is my replacement TV faulty.

    Please let me know and check your TV's, i want to check here before calling my dealer Monday and making a fool of myself.

    I would really appreciate some feedback it is driving me nuts just want to enjoy my me TV and stop worrying about it!

    Thanks all :confused:
     
  2. z00h

    z00h
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    see what happens if you turn the brightness down a tad
     
  3. BJQ1972

    BJQ1972
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    Google 'plasma dithering', and compare to what you are seeing.
     
  4. mikelj

    mikelj
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    The "snow" you can see when close to a plasma screen is dithering - a method which plasma must implement in order to reproduce the full range of colours. Without dithering the range of colours a plasma would be capable of reproducing would be very limited indeed. It is not a fault with your screen, just the nature of plasma.

    Different makes of plasma implement varying drive methods, because of which some rely more on dithering than others, for example Pioneers. For what its worth, imo Pannys have the cleanest image when it comes to dither noise. However, because of dithering, some people simply don't get on with plasma.

    If you don't see dither noise from your normal viewing distance then stop worrying and enjoy:).
     
  5. Scooby2000

    Scooby2000
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    What colour are these pixels? and how wide spread is it?

    Having brightness set wrong can create noise in blacks this is normal for plasma, to varying degrees. If its just a few scattered about the screen it could be missfiring pixels, this would show there's an issue with the set. Another thing it could be is megentar noise, this would appear in strips or bands on the set and be effected by changing gamma and or contrast.

    A picture would be of use.

    Edit: good post above and indeed if only seen up close this is likely what it is.

    As a side note to all, I have deleted some posts as of topic, a straight forward question is being asked here, this make vs that make arguments are not helpful, op has made his choice.
     
    Last edited: Aug 5, 2012
  6. Roon1

    Roon1
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    Thanks all for your input. After a bit of Googling as suggested it appears to be plasma dithering i am seeing, it just seems excessive and I have not noticed it before (but maybe I have not scrutinised the sets as much).

    For info, I have just bypassed the AV receiver (Onkyo 808, picture set to 'through') but the dithering is still there on all sources direct to TV, i have also tried all other HDMI inputs just in case.

    I understand dithering is normal for plasma's but couple more questions then if i may...

    Can dithering noise be variable or even excessive between sets?
    Is it worth having the dealer back to check?!

    Just seems too much!

    I am now going to have a play with the settings which are currently set to THX Cinema/Bright room depending if day or night with no other tweaks made thus far. Will let you know how i get on shortly.
     
  7. steverobertsbbc

    steverobertsbbc
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    It's perfectly normal, but you will be much happier when you set your brightness correctly. Put on a film with black letterbox bars in it and observe the letterbox. Turn down the brightness step by step and suddenly at one step the noise will disappear. This is the correct brightness setting.
     
  8. Roon1

    Roon1
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    I have just reduced the brightness settings and you are all correct the noise just suddenly reduces substantially and almost disappears.

    It is two or three notches though, but picture still looks good. I guess this is a trade off between supposedly almost perfectly calibrated picture and the noise.

    If you were to have a perfectly calibrated picture, as we all stive for, then does that calibration almost ignore the dithering effect in the pursuit of all the other aspects being spot on?

    I was thinking about professional calibration once run in that is all and wondered if the dithering would factor/improve when the experts do what they do or does it not come into it?

    Thanks all for putting my mind at rest and improving the performance of my set :smashin:
     
  9. steverobertsbbc

    steverobertsbbc
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    The correct level is the step where the noise completely disappears.
     
  10. mikelj

    mikelj
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    Yes, as stated in the above post setting up your screen correctly should minimise the noise in the black areas of the image. Professional calibration will achieve the optimal results from your TV, but whilst you are running in your screen, you can improve your picture by selecting the correct picture mode and setting contrast/brightness correctly.
     

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