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Is the Grayhawk screen designed to work well with all lcd, dlp and DILA projectors or only the higher lumen output models? For instance, will the Sony 400Q which has only 400 lumen output have improved performance with this type of screen?


Joe Andresen

Palo Alto, CA
 

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A better way to improve the black levels on the 400q is to tweak the polarizer plates. I had this done professionally, and now I am very satisfied with my black levels.
 

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Paul-


How is this done? (tweaking the plates)


I retired my old 400Q once I got my HT200 but if I could improve the black levels I would definately bring it back on in another room =)
 

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My Greyhawk works great with my JVC G11, much better blacks than with my old Stewart 130 (which was only 7 months old when I replaced it).

Based on my research, I would not spend the money for a Greyhawk if your source is a 400Q. You are paying more money for possibly worse results.
 

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See these posts:
http://www.thebigpicturedvd.com/cgi-...24&archive=yes


One comment: The author of the post probably had a burnt polarizer plate which prevented him from getting a uniformly dark screen. The author instead was maximizing the uniformity of the brightness on the screen to compensate for the burnt plate. The proper procedure for maximizing the contrast ratio is to adjust each of the three polarizer plates one at a time so that the least amount of light reaches the screen. As you move each plate ever so slightly, you will see the screen get brighter and darker. Once maximum darkness is found, tighten the bolt that holds the plate in position.
 

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I would like to thank Paul K for the link and Paul Hayward for the original article on adjusting the polarizer plates. WHAT AN IMPROVEMENT to my 400Q! It took me about an hour total to adjust the plates and then recalibrate with VE. Before I have a greenish gray black level and now I have a slightly blueish very dark gray black level, which I find nowhere near as objectionable. I am a blackaholic and now to my eyes when a scene has black in it, I actually believe it is black and not gray. Of course it is not black since I can still put my hand up and create a shadow of almost perfect black but perception is what counts. Even in movies like Dark City black seems very close to black.


If anyone with a 400Q has not tried this tweak, run, don't walk, down to your projector and try it. Now if I could find a projector that output 1000 lumens without increasing the black level of my now adjusted 400Q I would be one super happy home theater enthusiast.


One question: Would all LCD projectors be improved (possibly) by adjusting their polarizer plates? What about a DILA?


Chuck Anstey
 

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Chuck/Paul

When you adjusted the polarizer plates, did you block the light outputs from the other 2 plates while adjusting the 3rd? this was the procedure recommended to me by Dan at Sony service..


btw, when you adjust the polarizer plates, you change the grayscale and have to readjust the gain/bias settings using instrumentation. once that is accomplished, you can use Avia or VE (or both) to reestablish the correct color/contrast/brightness settings. If you adjusted the plates and didn't do this, you are not seeing what the 400 can really do http://www.avsforum.com/ubb/smile.gif


i'm trying the polarizer plate adjustment soon, and am going to take polaroids of DVD scenes before and after to see if a picture can show the difference in the tweak...


if either of you have any additional information regarding the procedure, i'd love to know it before i start disassembling my 400 and hurting the projector http://www.avsforum.com/ubb/smile.gif


thanks,

paul
 
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