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Discussion Starter #1
Things that bring out the rainbow effect:


Sitting to close.


High gain screen. This is a no no.

A dark screen such as the Stewart GrayHawk helps mask this effect.


Horizontal motion in the movie or the viewer moving his head/eyes in a horizontal plain


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Alan Gouger

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Belmore,


I don't see them very much at all on my LT150, but I'm sitting about 15' back on a 100" screen (1.5gain).


If I sit closer, I can definitely see them more frequently. So I think the distance and size of the screen is probably a big factor, like Alan says.


I like to have the whole screen in my entire field of vision without having to dart my eyes around or move my head. This may be partly why the rainbows don't bother me much.


I also found they nearly went away completely with a decent progressive scan DVD player through a component breakout cable. I don't have an HTPC so I can't say if that is better/worse.


In any case, try sitting back further or putting the projector closer. I think you'll also see it looks much brighter. I wouldn't recommend the LT150 for anything above a 100" screen.


But, having come from a Zenith CRT myself, I'm pretty happy about having a 3yr warranty and being able to replace bulbs in 5 minutes :) ....Not to mention getting that damn 100lb CRT off the ceiling!


-Dave

 

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Compared to you veterans in HT I'm really a newbie...but I must say that I have not noticed any rainbows on my LT150 throughout 4+ months of watching on the JVC. Actually I don't even know what it looks like can someone take a picture of it and post it? http://www.avsforum.com/ubb/biggrin.gif (Just kidding)


Truthfully though, that I suspect the "rainbow" might be related to adjustment/alignment/timing of sorts on the DLP color wheel. It can't be the DMD chip, can it? http://www.avsforum.com/ubb/smile.gif


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[This message has been edited by Yahoo (edited 07-07-2001).]
 

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Discussion Starter #4
I do not know what refresh rates the projector supports but if you are usng a HTPC you can try a different refresh rate. This will cause the wheel to spin at a different rate that may improve or make the effect worse.


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Alan Gouger

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I agree with many of your observations. I have a large screen (104" wide) that is high gain (2.0) and I sit fairly close maybe 13 feet or so. I haven't tried Alan suggestion of using a different refresh rates Does anyone have any suggestions? Of course, with HDTV, I don't really have a choice.


Thanks for all your responses. Let me reiterate that I don't want to discourage anyone from trying out the LT150. It is a bargain and the projector to beat at this price. My dilema is whether to retire my Zenith Pro900x and keep the LT150 or cough off the money to fix my Zenith. Not an easy choice. But for those looking for a first FP and are on limited budget, the choice will not be as difficult.
 

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Rainbow is not limited to the LT150. When I did my original shootout I had two guests with me and they both complained about rainbow with some of the other DLP projectors when using s-video. Lucky for me, this is only something I have seen once. When I switched to my dedicated and quite powerful HTPC (scaling to the projector's native resolution) the rainbow problem disappeared for one guest and the other found it was almost completely gone. My theory is that the superior scaling helps for some reason and also the faster refresh rate may also help!


Better to discover you have a problem with a $3,000.00 projector rather than a $10,000.00 one!


Cheers,


Grant
 

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This is just a friendly reminder about turning "white segment off". That may help rainbows too in addition to colors iirc from reading posts on this forum. It was also Grant's motto a while back http://www.avsforum.com/ubb/tongue.gif


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OK, last night I made a couple of posts praising the performance of the LT150, even compared to my Zenith CRT. After watching a couple of movies, I have to temper my enthusiasm, somewhat. Don't get me wrong, I'm not taking back anything that I said. This projector is a great deal (and even better today apparently!), but only if you can deal with the rainbows.


Apparently some people on this forum either don't see them or aren't bothered by them. I had a friend who within the last year bought a Dwin 700. We watched several different clips of DVDs and HDTV tapes. He was pretty awe struck and I think a little pissed that he recently spent $7k on projector that in many ways is inferior to this $3k DLP.


But we both saw the rainbows, maybe not at exactly the same time, but within the same areas of the clips we watched. I think his opinion was this was an acceptable trade-off for the increased sharpness, focus and awesome price.


I watched a couple more movies and I'm finding the rainbows to be more annoying. This time I tried not to look for them and see how often they pop up during normal movie watching. It's not constant and appears to very film/scene dependent. It always seems more frequent if the action or whatever causes you to move your eyes across the screen, from one object to another. On some material, I don't see them at all, on others (e.g. X-Men) and see them every 5 minutes or so. It's most noticeable in scenes with a black background and bright white objects in the foreground with sharp edges. Check out a crosshatch in Avia if you want to see it. Move close to the screen and move your eyes across the screen. It's enough of a distraction to make me stop and think about it. You know what I mean? The best movie experience is when I can become completely immersed in the movie with no distractions from whatever, compression artifacts, crappy sound, frame drops or this case, rainbows. I suppose I don't mind when I stop and think about how awesome a picture looks :)


I guess all I am saying is that "your mileage may vary". I wouldn't recommend anyone buy this projector sight unseen from a dealer that does not have a good return policy. I still don't know what I'm going to do. The picture really is incredibly good other than those @#$! rainbows!


[This message has been edited by belmore (edited 07-07-2001).]
 

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Are the rainbow effects more noticeable the closer you are to the screen or the larger the screen area to your field of vision. Can you attenuate the effect by sitting further back? (Not a viable option, I know.)


I'm wondering if I missed seeing them at Cedia because I was standing in the back of the room?
 

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I think that you are correct. As I said, the rainbows are more noticeable when you move your eyes from one area of the screen to another. I would imagine being further back should help this. Also, I believe the effect is very scene dependent. If you only watch bright scenes, I don't think you'll ever see the effect. Pop in X-Men and watch the fireworks (?) at the beginning (might be part of the beginning credits). If you don't see them here, I don't think you ever will.
 

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If you stand in front of the projector and look at the lens while turning your head you can see the same effect very easily. It seems like they bother me less than they used to, I hardly notice them. I do sit about 18ft back from the screen. I agree that it is scene dependent, especially black & white high contrast and when you mover your eyes across the screen. I think the further back you are the less you tend to do this.
 

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Quote:
Originally posted by belmore:
... As I said, the rainbows are more noticeable when you move your eyes from one area of the screen to another. I would imagine being further back should help this. Also, I believe the effect is very scene dependent. If you only watch bright scenes, I don't think you'll ever see the effect. Pop in X-Men and watch the fireworks (?) at the beginning (might be part of the beginning credits). If you don't see them here, I don't think you ever will.
got my pj today and this was the part i was dreading the most. i already knew i was one of the lucky ones who sees rainbows after seeing them on a Runco VX1c.

thankfully, i was pleasantly surprised more than once.

Yes there were still plenty of rainbows throughout the 6 hours i played around tonight, but they weren't 1/2 as bad as i expected they would be. X-Men was one of the worst offenders ( but the opening credits went by w/out a hitch...the rainbows became a problem with all the chrome and sharp angles used throughout the movie). the one piece of film i was really dreading was the opening credits to superman. i've played this about 30 times the last month, and with all the sharp angles, hi-contrast, and motion, i thought for sure this would be a nightmare.

Nope, another sterling score.

amazingly the LT150 performed better in this regard than the $17000 Runco.

in fact, i was happily surprised by how much i didn't see them. time and time again, scenes that i thought would be hell to sit thru, turned out to be rainbow free.

so , while rainbows will always be with me and this pj to a point, they don't look like they will be the menace i thought they would.

thankfully.

i was using an interlaced signial via s-video and the scaling artifacts were MUCH more bothersome than the rainbow situation. a scaler , progressive scan player, or HTPC is definately in the future. along with a hi-power screen.
 

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I must say...

2 weeks ago, my wife and I tested the NEC LT-155 with the Marantz 3100, and after about 6 hours of fine tuning we were very pleased with what we were watching.


Tonight we tested the LT-150 with the Marantz 7100, and well...

After all the positive things I have read on the 150, we were somewhat disappointed.

First with the pros.

The LT-150 seemed easier to fine tune (not sure why)

Color seemed to have a little more impact.

Quieter then the 155.


Now the cons.

Remote sucks!

RAINBOWS!

Can't even see the screen with the lights on.


Tonight I learned what rainbows are.

And I must say that they were very distracting.

So I asked my wife if see noticed any thing weird about the picture, she said no.

So half way through Gladiator I pointed them out to her.

My suggestion, if someone doesn't see them, don't point them out.

It ruined the movie for her.

I do have to say that near the end of the movie, it didn't seem to bother me as much.

Just wasn't a selling point for her.

I am glad I took it for a test drive first.

So far We like the LT-155 a little more.

We will spend the rest of the weekend playing with this thing, if things change, I'll post.


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Eddy
 

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Rainbows and DLPs, for some, go hand in hand. There are a couple of recent posts on the forum with some ideas about how to ameliorate this artifact. Here are some suggestions with respect to the LT150 from someone who hardly ever sees them, so take them with a grain of salt.


1. Mask down the size of your screen or sit further back so that you do not have to move your eyes much to follow the action.

2. Cut the contrast a little at a time and see if this helps.

3. Turn off the "white segment" (projector options, page four - I think).*

4. A grey screen might help, but I think with this projector there's a big trade off with loss of vitality vis a vis colour and also a loss of "punch".

5. Try a better feed - I guess you have already tried a progressive scan DVD player (this makes a very large difference for many). Next you could try a HTPC, but if this doesn't help then I think you're out of luck so -

6. Go with a different projector.


Rainbow, I guess, is as big a problem for you as the grid or "screendoor" effect is for me. When I first had the LT155 in my home theatre I expected it was the one to beat and had been told that it would be the one I would like. I loved it, except for the screendoor effect - it was a deal killer for me just like rainbow may be for you! Some people don't see the screendoor effect until it is pointed out to them, just like rainbows, however, once you see it you'll always see it. With the new DLPs rainbow shouldn't be a factor - problem is these things are expensive and it may take awhile before this technology filters down to products with more consumer friendly pricing.


If you go with the LT155 seriously consider a grey screen. I am sure that one of the reasons people like grey screens with LCDs is that they help mask the "screendoor".


Everyone visiting this forum have been advised many times over to check out products before buying - particularly "rainbow" with DLPs and "screndoor" with LCDs. Don't complain if you have a problem with either.


* I have been experimenting with the "white segment" on and have a couple of observations. There seems to be an improvement in contrast or crispness, but it comes at a price. I see some (very little) video noise increase, but not really palpable, with the good transfers, and also a rainbow here and there, and that's with my HTPC as the feed.

With the screen I am using the colours seem just as good with the "white segment" on as with it off. I now leave the "white segment" on and only turn it off if the particular DVD I am watching has a problem with video noise.


Cheers,


Grant
 

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Thanx Grant

I'll give these a try.

I have noticed that playing with the contrast does make a difference.

With the LT-155 the screen door didn't really bother me, and I wasn't using progressive scan.(if it makes a diff)

Trust me, I won't be pointing this out to my wife!


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Marantz SR-19

Marantz DV-7100

Energy Encore II

JVC 32PIP

looking for FP(LT-150)

Digital Cable Box

Aura Bass shakers


Eddy
 

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I have an LT154 which is the same as the 155 with 300 less lumens. I still feel that it is acceptable even in ECO mode so I can get double bulb life.


Here are my personal results of my testing. I can't see how these tests would be any different for other NEC projectors whether DLP or LCD at the same XGA resolution.


Using Coaxial - Don't do it..


Using S-Video - Only for your DirecTV/S-VHS


Using Standard DVD w/S-Video - Looks very fuzzy and out of focus, colors are muted, brightness is low.


Using Standard DVD w/Component - Better but still fuzzy and low brightness.


Using Progressive-DVD w/S-Video - Why??


Using Progressive-DVD w/Component - Much better, very crisp image. Brightness is excellent, almost twice as bright. Colors are deep and vivid. But, the image shows jaggies. I do not know why. Any diagonal line will show this. The pro's still outweigh the con's though. I would say it is acceptable.


Using HTPC/Radeon w/XGA - Incredible picture, colors, brightness. Absolutely better than a Progressive Player in my testing. Matching the native resolution is the "KEY".



Conclusion: Why can't they make a DVD player that has a menu to select screen resolution to match your display device and have a VGA out? The HTPC is great, but I like the ease of use of a standard player. Also, the noise is a problem for me on the HTPC, and I have tried many sound reducing methods. I was hoping that the Progressive Player would be closer to an HTPC but it is not the case for me. I still need my HTPC and will continue to until I see a DVD player that works as good as my PC. The player I used is a Sony DVP-NS700P.


Has anybody seen a progressive-player that comes close to an HTPC? I have not..

 

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I am using WinDVD with the Radeon in my HTPC.


Dsspotato,


I have two proscan DVD players and there seems to be huge differences between them. My old one, a Toshiba 5109 is producing an image that is very close to my HTPC. I used to think that the scaler in the LT150 wasn't all that good, however, now I think that the DVD player has a lot to do with it. To put it mildly, I am shocked at the performance of the 5109 and very pleased with it (especially considering that it is not considered to be even close in performance to my other player - go figure!). I am rather disappointed in the other one though - I think the new Kenwood would certainly be the one to try! I seem to be learning something every day. Remember that most of the DVDs I use with the 5109 are good ones.


Cheers,


Grant
 

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Thanks Grant, but this is all too crazy. All I want is to get a DVD player that rivals my HTPC. I wonder if there is a shop that would let me bring in my projector (It is portable your know and comes with a nice little carrying case) and plug it into different proscan players to find out which one works best. I am sure that many on this forum have come close to this but there is no single consensus for a player like there seems to be for a projector (LT150). At least for the moment.


Denon DVD

Pioneer DVD

Toshiba DVD

Sony DVD

Panasonic DVD

Yamaha DVD


AAAAAAAAHHHHHHHHRRRRRRGGGGGGGGG!!!!!!!!!


I don't want to buy/return, buy/return etc...


I will continue to use HTPC and live with the noise, wireless mouse, keyboard etc until I know...


I wait....
 

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I have about 40 hours of viewing time on my LT150.


Neither my wife or I have seen a single rainbow. This includes watching the Clerks DVD (a high contract black and white movie). Also we have watched DirecTV through an Iscan v.1 and no rainbows.


Setup is :

LT150

100" 4:3 Vu-tec screen w/ 1.3 gain screen

HTPC - Hercules Prophet IIMX (GeForce II) @1024x768, 72Hz Refresh

WinDVD 2.8
 
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