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THX Optimiser

Discussion in 'Plasma TVs' started by Geordie Jester, Nov 4, 2003.

  1. Geordie Jester

    Geordie Jester
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    Hi guys,

    Leaving my lip-sync problems behind for the moment (!).......

    ....actually saying that I have 'noticed' a lot less lately. I am sure it's just that Im not being so critical of the system now. DVD is definately worse than cable TV though (which seems strange, knowing the SKy/cable sync probs in general)

    I have a question about the THX Optimiser that is present on a few of the DVD's I have.

    I have been playing with optimising the video. (using panny 6 42" plasma) All of the test seem to work well and I am really happy with the results. Just one thing though. I have difficulty running the first contrast test. Basically not a lot happens as I move from extremes of contrast setting (-30/+30). I can just make out a different shade of white in two corners, but the test mentions 4 shades in 8 boxes. Its as if its bleaching too much to see definition (but not bleeding at all into the black). I have set the brightness to the correct level on the next test, and the sharpeness is fine too.

    Anyone know how to tweak advanced settings to help me achieve better results? My gut feelings is that almost the contrast is too high (even on lowest setting). the whites are very white and the blacks are very black (but fine). in fact low-light movie scenes are really impressive i've noticed.

    Anything you can suggest then please chip-in !


    Regards


    Paul
     
  2. Geordie Jester

    Geordie Jester
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    Reading more and more on this topic, am I right to assume that not being able to break out four shades is not too big a problem ? Or should I really be able to see a change as I move the contrast setting ?

    I have set the Contrast to -30 in the meantime as Ive heard its best to run at a lower level.

    Can someone with a panny6 and Optimiser let me know if theirs shows much difference in the test pattern when moving Contrast ?

    Definately during movies I get the feeling the whites are getting fired too bright, but that the handling of the dark scenes is staying great.
     
  3. Costas

    Costas
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    Hi GJ,

    I have noticed the same thing using the THX optimiser with the Pio 434 and before the 433. It takes a hell of a lot of contrast increase to lose the definition of the 8 boxes and equally you can see them all being there for most of the around "mid" contrast values. Having been able to do all other tests OK, I have chosen for contrast the value that shows a second small "fainiting" line shadow on the perimeter of each box. This is about 5 divisions below the "standard" setting from Pioneer which is always set up rather high. Not sure if my approach is correct but I would welcome more inputs here..someone must know!

    I have also tried the AVIA disc (only NTSC dedicated) and again contrast there for the two moving lines can go up or down a lot.
    However my suggested readings on THX and AVIA do come quite close.
     
  4. Geordie Jester

    Geordie Jester
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    Are we not getting opposite results though ?

    you said "It takes a hell of a lot of contrast increase to lose the definition of the 8 boxes ". Whereas, Im not actually getting any definition of the 8 boxes at any value of contrast! I can see a slightly different shade in the boxes in the bottom corners but nothing really changes by changing contrast. I certainly can't see four shades at all at any setting.

    *** maybe its because Im still in the first 100hrs of use ?! I know that it has been said on here that calibration shouldn't really be done until after this point.
     
  5. Costas

    Costas
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    Oops! Sorry I did miss a bit... Well, that is rather strange especially if you did all other testsOK! As mentioned in my case, the contrast on the new 434 (definitely less than 100 hours old)
    goes from 0 to +60. The "standard" factory setting is on 40 and at around 49 you lose all 8 boxes. My setting is 35-36 where I see the fainitng "edge" on each box but all shades of the boxes are clearly visible from reading 20 upwards...

    Hey, rest of Pio and Panny owners..any input / help?
     
  6. Geordie Jester

    Geordie Jester
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    hmm yeah. it's like I need the contrast setting to go even lower than -30 !! which makes me wonder if I can do that by tweaking an advanced setting.
     
  7. gmt steve

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    I helped set up a friends PW6 and noticed the same problem with the THX contrast pattern. I think it must be because the circuits which drive the panel are clipping the signal. ie. not allowing 100IRE to be shown. I think the THX test pattern is several boxes with 98 & 100 IRE levels. So if the panel won't show any deliniation between the two it must be clipping the 100IRE and 'mushing' the two levels into one.
     
  8. Geordie Jester

    Geordie Jester
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    Good news to hear that someone has seen the exact same thing happen.

    Any possible way to get 'round it. ? Do I need to ?
     
  9. cwick

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    Found this which contains this ...

     
  10. Geordie Jester

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    thanks cwick. I did see and read this article also. it sounds like the pw6 is clamping the white but that lowering contrast (white level) to -30 is not low enough for some reason.

    or are you mainly referring to the first line that says a plasma test pattern needs to be different to a CRT one. In which case the DVD test maybe more suited to a 'normal' TV ?

    cheers
     
  11. Costas

    Costas
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    cwick, this is good information indeed. Is there anything similar available for the Pioneer screens?
     
  12. cwick

    cwick
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    Not sure what I'm referring to :(

    I've only used Avia to calibrate my Panny 6. It calibrates, as best I can tell, to about -8 contrast, which looks great for DVDs viewing in a darkened room. I have to knock it up to 0 for normal viewing (daylight or lights-on), so I just toggle between the two modes.

    Have to say though that even using Avia it's a bugger to get contrast right. The brightness test is easy - tweak 'till you can't see one of the bars. The contrast is too subjective - tweak 'til it looks about right seems to be the way to go.
     
  13. Paden

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    Geordie Jester, I had the same trouble with my panel using the THX Optimiser but in my case the DVD also has a contrast setting & once this was reduced all boxes became visible.
    Do you have a similar adjustment on your player?

    Cheers, Paul
     
  14. silverx

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    I have a pw6 and the THX works fine - using the 'normal' picture setting the 8 boxes are visible at the presets. When i used a rgb scart i needed to boost the contrast a little but since i put the component board in the presets are about right.
    Good point about the dvd player - mine (arcam diva) has 2 settings for black - I think this applies to NTSC only though, but it does make a difference.
     
  15. Tee Tee

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    I have exactly the same problem with my Panny 6 and THX optimiser.

    The solution I found was to go into Advanced settings and turn down the Input Level a lot. The white boxes become easy to differentiate then. Trouble is, I'm not sure what input level actually does and whether the changes I'm making have a detrimental effect elsewhere! The manual is worse than useless on this (and almost any other) picture tweaking facility.
     
  16. Paden

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    Amen to that!
    I found the Optimiser contrast test pattern the easiest to use but after I'd set it up I still thought it was too bright.
    I'm now running my panel on "auto" where I believe the panel works out it's own contrast setting & things seem better.
    (saving my pennies to have it ISF'd & maybe a scaler attached :D )

    Cheers, Paul
     
  17. Costas

    Costas
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  18. Geordie Jester

    Geordie Jester
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    Thanks for the replies guys. I don't believe there are any contrast/picture settings on the DVD player.

    I also played with the Input Level and found that moving it does a help a little bit. I take it a minus input level is simply decreasing the overall range of signals? Does anyone know whether this means you lose quality as you are effectively squeezing more levels into a smaller band ?
     
  19. gmt steve

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    Have you looked at the contrast level when the panel is set to auto? It's maxed out! I hoped Auto would work well (it's great on my Sharp 22" LCD), but when it chooses maximum contrast in a darkened room, forget it.
     
  20. Paden

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    Yeah I did notice that gmt steve but you can then crank it all the way down to -30 with no change on screen :confused:
    All the other settings still seem effective.
    That's how I've left it, for the moment.

    Cheers, Paul
     

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