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While watching Forrest Gump over the weekend I was playing around with LT150 projector settings and accidently turned the white segment on.


I was in one of the menu screens which are pretty much pure white and BAAAAAMMMM! Turning on the white segment made it much whiter, turning it off dulled it down quite a bit.


I then watched some of the movie and contrast ratio most definitely improved. Was it Thumper who measured significantly higher contrast ratio with white segment on?


I didn't notice an increase in rainbows and didn't notice any noise or "crawlies" and I don't really want to go looking for them.


Does anyone know exactly what happens internally when switching white segment on or off? When on, does the projector display RGBWRGBW, when off how does it skip the white section? Does it speed up the color wheel to just do RGB or does the color wheel remain at a constant speed and firmware just turn the mirrors "off" during the white section?


Anyway, I found the picture more pleasing (at least initially) with white segment on and will run with it for a while. If Grant were dead, he'd be rolling over in his grave right now...


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Tom L.

NEC LT150 FAQ

My stuff, pictures, HTPC, and screen tests
 

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I think this was discussed in another thread recently. If I remember correctly it seems that for new release/very good tranfers that the best picture is with white segment on. I'm not sure what this does internally but I would guess it turns the mirrors on/off as the white segment passes the light. If you see crawlies or other artifacts then turn it back off.
 

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tlastrange,


I had been using the LT150 with WHITE SEGMENTS ON happily for months before reading Grant's notes on turning that off to get better color in the picture. Sure enough the brightness went down but the fidelity of the colors were subtlely better if you look carefully.


With the high-power screen there doesn't seem to be any problem with the brightness. http://www.avsforum.com/ubb/smile.gif


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I myself have been watching for over a month with the White Segment "OFF".


Then about a week ago I turned it "ON" and for me there's no way in hell I'm going back to off. I found the picture soo much better with it "ON".


Remember that I watch practically all in HD. I'll never go back to normal TV.


Regards,
 

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I had the exact same impression as Bob. No difference at all. I played with this quite a bit, flipping it on and off with both light and dark scenes to analyze the difference.


Which makes me wonder...Does the projector need to be rebooted for this change to take effect?


--Les
 

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I definitely see a brightness improvement with White Segment On. I have not clearly seen the downside. Still, I have left it off for DVD's based on the near-universal recommendations I have heard here. Can someone describe the downside of WS On in greater detail? I seem to remember Grant saying it reduces "crawlies", but I am not sure what the little creatures are. I'd love to have the additional brightness if the drawbacks are not things I notice.


John
 

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Tom, my understanding of the white segment comes from the perspicacious Mr. Wigggles' posts before his self-imposed exile. The white segment, as I understand it is the white section of the colour wheel and just how this is turned off or on is beyond me.


Just for the record I too leave the white segment "on" most of the time - the image seems a little more crisp to me. I turn it of for movies like City of Angles - there are some sky scenes (where Meg Ryan drives across bridge etc.) that exhibit crawlies (swarm of insects in sky). Most good recent DVDs don't have this problem, so the white segment stays on. And yes, apparently it was Thumper that measured the LT150's contrast ratio at 1000:1 with the white segment left on.


Cheers,


Grant
 

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Les,


I may be wrong but I think like with every other adjustment

change if you press "enter" before you leave the menu page it will make the change. Just like you I still have not noticed any brightness difference regardless of what I'm viewing when I make the change.


As far as technical explanations I think what's at work is magic. I am stupified and mystified by the notion that you can take a monochrome projection panel and then spin a wheel in front of it with red, green and blue segments to get a picture. And I can't even begin to comprehend how a

a bunch of microscopic mirrors could constantly be moving inside the thing and the whole thing not just fall apart in 5 minutes. So frankly I don't believe in any of that. There ain't no such thing. No tiny mirrors or spinning wheels. My best guess is there is a little elf in there using magic to make the picture come out.


Bob


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Selecting white segment on provides an artificial boost to near white IREs. You can see this clearly with AVIA or video essentials on the gray scale ramps. Turning on white segment basically makes your gray scale non-linear.
 

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So, is leaving it on good or bad. Seems as if there is no consensus here. I really can't see much difference except that I have seen crawlies from time to time when leaving it on.
 

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Bob,


I agree, and have started leaving a plate of small cookies and a thimble of milk out at night.


Since then, my brightness has improved, and contrast seems to have also improved.


Right now I'm running some tests to see what the little elf likes, and will report back to you. I can only hassard that after your 25' projection onto the side of the house, that the little elf was pretty worn out, and hankering for a thimble full of that Crown Royal.


Kelly
 

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You know, Kelly, on that night I think I actually saw that little sucker (saw other things too, haha).


I wish it had been Crown Royal instead of that rotgut Canadian Mist. Me and the elf would have felt better on Sunday. http://www.avsforum.com/ubb/smile.gif


Bob


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[This message has been edited by RobertWood (edited 09-05-2001).]
 

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I take back what I said earlier about not seeing the negative artifacts from White Segment On. Just watched "Unforgiven", a truly abysmal transfer (easily the worst looking DVD I have seen) and the broad skies were alive with crawlies. Turning off the White Segment definitely improved the picture. So my conclusion: on newer, well-mastered DVDs I'll get some extra brightness by turning on the White Segment; for some films, though, it's definitely best to keep it off. Great, one more thing I can tweak when watching a movie (it's a sickness).


By the way, Bob, your elf post is so funny and true. An elf seems much more plausible than the absurd notion of a wildly spinning color wheel and a vast array of shifting mirrors. I refuse to believe it's possible, much less able to make such a beautiful image. http://www.avsforum.com/ubb/smile.gif


John
 

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John,


In don't disagree about the quality of the transfer.

But gosh how I love that movie. Some of the juiciest roles ever for Eastwood, Hackman and Harris all three. Brilliantly executed from start to ending. Being 51 years old I now rate movies with my Snooz-o-meter (how many times I nod off during the film). This one rates a perfect no snooze. A character named English Bob and a town named Big Whiskey. Who could ask for more.


Bob


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Tom


just saw your site. fabulous!! so many information and experiences. I'm lurking on the NEC LT150 myself. The tests of different screens is very useful, priceless.


Thanks

David
 

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Hmmm. Thats odd. I opened mine and instead of an elf I found a Flintstone bird. Little suckers fast with the paint brush.


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Gonna name my HT "Tooth and Nails" for the battle my wife is putting up against it.
 
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