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LG 37" Plasma Calibration Experience

post #1 of 10
5/24/08 at 8:58pm
Thread Starter 
Using DVE-03, here are my results for my neighbor's LCD(model number undetermined): THIS IS AN LCD I APOLOGIZE for misleading folks with my header. I am quite the dyslexic fool and continually call things by what they are not! I hate being this way more than you will know!

The left figures are factory / right figures are post-adjustment.

TV warmup time: 10-15min @ factory settings.

DVD Player: Panasonic DVDS25. Picture mode: Normal. Connection: Component.

Cable Source: Optimum iO Sci-Atlanta DVR-HD. Connection: Component.


Picture Mode: Dynamic / User1(Cinema, Sport, etc. does not allow adjustments)
Color Temperature: High / Low
Backlight: 100 / 50
N/R, Auto-Contrast, Auto-Black: Auto / OFF

Contrast: 100 / 88
Brightness: 40 / 32
Color: 70 / 47
Sharpness: 70 / 19
Hue: 0 / R1


My immediate impressions:
Color & detail much improved over factory settings. Got that "pinch myself, am I there?" feeling when watching MSN-HD or PBS-HD.
BUT: Low end of picture *wasn't even there!*. Some guy on C-Span was giving a lecture. He had on a black shirt against black pipe & drape. His face seemed to float in midair like the grinning Cheshire cat in Wonderland!

I checked the Advanced portion of User Picture settings, nothing stood out.

I then fiddled with the black level, and had to raise it up to about 55-60 before the outline and texture of his shirt stood out from the background. This seemed to help on other channels, standard and HD. Suit jackets and scenes with shade definitely appeared realistically at *my* setting.

I'm pretty sure I ajdusted black-level correctly: of the two pairs of 3 dark columns, I adjusted the second brightest column(2%) so it was just visible. This rendered the 4% column very visible, and I could not see the 0% at all.

This is my first real experience doing basic calibration on a brand name LCD TV. Let me know what I could have done better with the Brightness control in setting black level, and if I set it properly. There are no provisions for gamma in the user or advanced user settings, and at least to my eye, little midrange adjustment seemed necessary. Measurements may reveal otherwise.
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post #2 of 10
5/25/08 at 5:00pm
Thread Starter 
Anyone alive out there?
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post #3 of 10
5/26/08 at 6:39am
Greetings

You use a signal generator to calibrate cable/satellite. Unless you know which channel puts out a reference signal. (The answer would be none of them.) Then you cross your fingers and hope for the best.

Regards
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post #4 of 10
5/26/08 at 8:39am
Thread Starter 
Quote:
Originally Posted by Michael TLV View Post

Greetings

You use a signal generator to calibrate cable/satellite. Unless you know which channel puts out a reference signal. (The answer would be none of them.) Then you cross your fingers and hope for the best.

Regards

I wasn't calibrating the iO DVR. I was doing the TV. I just like to mention all equipment involved and types of connections to give an idea of the setup.

I was looking for opinions/suggs on why the Brightness setting I got with DVE-03 resulted in such crushed blacks.

This is not the first time I've had to forgo the DVE suggested setting and turn black level up past the midpoint - as with many a directview "tube" in the past.

It appears much much much more realistic at 61 than at the 32 I derived with DVE.

Any reason why?
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post #5 of 10
5/26/08 at 10:35am
Greetings

Because your DVD player likely is not providing you with a reference signal. Parts tolerance issues can do that to you.

Assuming the DVD player is a reference device would not be a good place to start. (maybe it is and maybe not, but you have to compare it to a signal generator to know more.)

And then you have to look at if the DVD player is actually set up right by itself.

Regards
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post #6 of 10
5/26/08 at 10:42am
Quote:


Any reason why?

Michael gave you the reason, but you would need to have a basic understanding of consumer video signal sources to comprehend his point. You can't expect a cable service provider's signals to behave like those from a calibration program through a DVD player. Even though you were "doing the TV," you used test patterns played on one device, but apparently are expecting a different device to look the same with other programming.

Not only can different signal source devices contribute their own peculiar non-linearities, but broadcast programs can vary as well from one program to another. There's also another variable in the case of cable TV signals, and that's what the cable company does to the signal along the way to its delivery to your location. Using different interconnect cabling can also introduce variations in signal behavior.

It's the same old principle: "garbage in, garbage out." That doesn't necessarily mean cable signals are all "garbage." It means that your display device must be adjusted to compensate for irregularities between source devices and program signals. Michael's subsequent post brings up another extremely important issue- DVD players have their own picture settings that must be taken into account.

Best regards and beautiful pictures,
G. Alan Brown, President
CinemaQuest, Inc.

"Advancing the art and science of electronic imaging"
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post #7 of 10
5/26/08 at 10:52am
Michael is right. You can't calibrate for cable using a DVD. You can only use a signal generator and hope that the end results somewhat match up with your local cable/sattelite feed. Each calibration you do is only good for the 1 input you are using when it's being fed by the particular source you are using. That calibration may be close for other inputs/sources, but then again it may not. You can only judge the DVD calibration you did by watching DVDs on that DVD player using that input.

To add onto what George said, also some TVs may behave differently per input type. HDMI results may be completely different from a component input. Same for the difference between whatever your DVD player is connected with and the cable input on the TV.
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post #8 of 10
5/26/08 at 11:42am
It is not just a question of getting a reference signal generator. You also have the question of the porch setting. DVD players often have a light and a dark porch for black level as do signal generators.

I am fairly sure that our local cable system uses a different level of reference black for SD than they use for HD.

There are no perfect solutions.

One thing you can do if you have a DVR is pause a pre-recorded program during a fade-to-black sequence and then set the Brightness level at that point where lowering the setting no longer results in a lower measured black level.
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post #9 of 10
5/26/08 at 1:23pm
Thread Starter 
Quote:
Originally Posted by GeorgeAB View Post

Michael gave you the reason, but you would need to have a basic understanding of consumer video signal sources to comprehend his point. You can't expect a cable service provider's signals to behave like those from a calibration program through a DVD player. Even though you were "doing the TV," you used test patterns played on one device, but apparently are expecting a different device to look the same with other programming.

Not only can different signal source devices contribute their own peculiar non-linearities, but broadcast programs can vary as well from one program to another. There's also another variable in the case of cable TV signals, and that's what the cable company does to the signal along the way to its delivery to your location. Using different interconnect cabling can also introduce variations in signal behavior.

It's the same old principle: "garbage in, garbage out." That doesn't necessarily mean cable signals are all "garbage." It means that your display device must be adjusted to compensate for irregularities between source devices and program signals. Michael's subsequent post brings up another extremely important issue- DVD players have their own picture settings that must be taken into account.

Best regards and beautiful pictures,
G. Alan Brown, President
CinemaQuest, Inc.

"Advancing the art and science of electronic imaging"


I am aware of the (sometimes wiiiiide) variation in consumer equipment levels, but this(LG situation) was something else. On my own combination,(24" Direct-view Toshiba and JVC VHS-DVD combo), the results I got passed reasonably accurate results for cable & VHS viewing as well as DVD.

Per your's and TLV's final point: As for my neighbor's Panasonic DVD player, I made sure that any picture adjustment options were "normal" or "standard". The player had even a Cinema(!) mode, but I simply did not want to take the chance of biasing/altering the DVE patterns before they hit the LG screen.

The LG Remote also has a "bright" up & down buttons on it(on either side of the Menu button), in addition to the User Brightness control AND backlight, in the user menu. I left it in center position. Could LG make things any more confusing?

http://www.imagecows.com/display.php...lcdtv-2-01.jpg


Now this is what I like to talk about here George, but being the socially cluelessthat I am, I didn't immediately consider that I was posting over the Memorial weekend and that a lot of people might be away from the AVS forums.

But again, nice to be talking shop with you and the others.
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post #10 of 10
5/28/08 at 4:57pm
Quote:
Originally Posted by TomHuffman View Post

One thing you can do if you have a DVR is pause a pre-recorded program during a fade-to-black sequence and then set the Brightness level at that point where lowering the setting no longer results in a lower measured black level.

Actually, I am using the same approach and for DVD sources as well.
Put up a video black field and do the same adjusting of brightness,
until it doesn't darken the screen anymore.
For LCD, then adjust with the backlight on how dark black should look.
Gamma ends up a bit higher than 2.2 but I get the best, darkest, blacks
the display can produce.
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