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Discussion Starter #1
I just wanted to put this in its own thread. This was NOT refering to the LT150, which for its price doesn't matter what flaws it has.

It was refering to those $8000+ single chip DLP's.


"As I have said before, and repeated again, out come my fellow Rainbow Crusaders.


In fact, I had a very long argument with another member about rainbows, which he denied was a problem.


My logical argument: WHY then are companies coming out with faster colour wheels, to fix something that isn't a problem? Obviously, it is a problem they recognize. I also responded by questioning how any company could release a product with such an inherint flaw.


My point, it is of no use to the rest to say "I don't see rainbows, so it doesn't exist." To go out of your way to try to avoid them is wasting your own time and money. So, after you spend 10K which is ALOT of money for what amounts to a "toy" You start to see rainbows, and realize you wasted your money. Once you see it, you WILL look for it, you WILL notice it.


However, this does not mean that there are not those who do not see the "colour separation artifacts." Some people can try all they want, and not see them. However, this is a very big problem...because anyone can say they see them, and then the rest of us know that there is some possibility that we might see it if we buy that particular projector. But when someone says they DON't see it, that can mean absolutely nothing."


What does this mean? It means that, unfortunately, we will never truly have a benchmark for rainbow testing on single chip DLP's. Unless there is some scientific method to determine when the colour wheel speed is fast enought that no one can see it, I, at least will be permanetly hesitant when dealing with scDLP.


However, I assume that this is because of the business market focus. However, I will never know how Seleco, Dwin, Sharp have the nerve to charge so much, for a product that has an inherint flaw. Here in Canada, I could buy a fairly nice used car for the price of these projectors.


I had asked, before, why not make a 10 speed colour wheel. No true answer was really concluded, and that is obviously stuck in the heads of Sharps and others engineers minds. If you are already goign to have such an expensive machine....get the colour wheel right. Ie...FASTER...however, I assume that the brings its own problems, but they won't be rainbow.


What IS the speed at which the rainbow artifact will not be seen? I don't know. But if they just go overboard...a 20X colour wheel..hehehe...then I am sure we won't have the problem.


I guess all they have to do is make the colour wheel twice the size, with twice the number of elements on it, and that would effectivly double the rate. Then, speed it up...


I, however, cannot really discuss the colourimetric issues involved with the colour wheel. I will leave that up to Milori and others to discuss.


Remember my point, for a 2-4K dollar projector, this, I guess is part of the sacrifice. When you start getting into the higher price ranges, this is unacceptable. And we know it, and the companies know it, or else they we would still be at 1x 3segment colour wheels. I guess they just haven't gotten it completely right.
 

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David - you're absolutely right! The same holds true for LCD. I saw a Sony set up properly on a small screen and from a long viewing distance and it looked great! I have since seen it in different surroundings and the screendoor was intolerable. If I had purchased it after my initial viewing I would have been very disappointed since I couldn't have replicated the same setup and would have had to deal with screendoor. The same goes for DLPs and rainbow. Both of these problems should be explained to the potential customer and the customer can check it out for him/herself. I would think a lenient return or exchange policy would help customer relations.


Defective? I don't think this is the right word. If only 10% of the population has a problem with it , is it defective? If I were 6 feet 6 inches tall (less that 10% of the population) could I call most automobilies defective because they don't provide enough headroom for me? I don't think so.


Should this technology be pulled from the marketplace until it is "perfect" for the last 10%, 5%, 1% of the population? I would be upset if they did this!


I do see rainbows, but not often. I don't consider DLPs defective nor do I consider LCD technology defective. They are what they are and both are improving. One of my old computers now seems defective compared to my new one because it can't do much and is so slow. Things will improve and are improving.


A forum friend of mine just purchased a 150 pound CRT for a very good price. He won't have a problem with screendoor or rainbow with it and he can use it for weight lifting as well - CRT is always an option for you too. ;)


Oh the impatience of youth.


Cheers,


Grant
 

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I would agree with Grant that I don't consider this to be a defect. I would say that it is a limitation of DLPs as compared to other FP technologies and a limitation which one day may/may not be reduced/eliminated. The fact is, all of the FP technologies have their own sets of limitations.


For me, my biggest factors in deciding what to buy were cost and size. By size, I don't mean that I needed an ultralight FP like the LT85 that I ended up with, more that I could not deal with the size of a CRT projector in my relatively small living room.


Do I agree that these 10K DLPs are overpriced? IMO, yes. Of course, I'd probably the same about any 10K home projector, regardless of its performance.


Scott
 

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David, I'm sorry, but I really object to your characterization of the DLP rainbow as an "inherent flaw". All display devices have strong points and weak points. All of them make tradeoffs in one way or another. DLP has made a cost tradeoff for the single-chip projectors that can produce a particular visual artifact. In return, you get a phenomenally sharp picture with excellent color and brightness. Some of us are willing to accept that tradeoff, and some aren't.


I could enumerate the weak points of D-ILA, LCD, CRT, etc, but I don't think it's worth the time. Suffice it to say, they all have both strong and weak points.


I think just about anybody on this forum would agree with the statment "Try it before you buy it" for all of these machines. Evaluate for yourself. I tried an LT150 and a Sharp 9000. I found the rainbow too distracting on the LT150, but barely noticeable on the 9000. I chose the 9000.


Interestingly, I had a similar reaction to MPEG-2 video (Dish, DirecTV, ReplayTV, TiVo). I found the macroblocking artifacts to be distracting. However, I accepted the tradeoff of what these devices allowed me to get (interference-free satellite video, super-convenient video recording) in exchange for the artifacts. I still see them, but I'm not "bothered" by them. I made my choice and I'm comfortable with it.
 

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Interesting rant, David. :D


The shame of it all is that DLP is a really, truly amazing technology! Three-chip DLPs produce some of the best pictures I've seen from any digital projectors and (dare I say it) can beat D-ILA to claim the crown of king of the digital projector mountain. It's that pure red, green and blue primary that do it. Excellent picture, even for the very discerning videophile.


No, DLP is certainly not defective. In fact, it can be completely *amazing*. It's the color wheel compromise that's the cause of all the single-chip DLP problems (rainbow, noise and color errors).


ANY projector with a spinning color wheel would have the same problem, though. There is a company developing a single-panel LCOS (D-ILA) projector with a spinning color wheel that (IMO) will be a big flop...but only because of the color wheel. Even though it will be LCOS, I won't be interested in it.


With clever engineering, the problems may be solved someday, but it is very hard to spin a wheel in front of a light source and come up with a pure Green, as if even a tiny amount of the red part of the wheel gets through you have yellow (additive light sources...Green+Red=Yellowish greens). I am not saying that it can't be done, but that I haven't seen greens on a single-chip DLP that could match a three-chip DLP (or even LCD or LCOS).


I agree that for inexpensive units, you sign up for certain compromises. However, for >$7K, I would be looking for three pure primaries...and not orange-reds or yellow-greens, either. For that kind of money, give me one accurate RED, one accurate GREEN and one accurate BLUE primary in the image simultaneously.


Would most non-videophile folks notice any problems at all? Probably not. Plus, for business presentations, it's a no brainer. scDLP are light, bright, inexpensive and simply great for that market.


It's when the price starts to get into the $7K, $8K, $10K range that the color wheel starts to look less attractive to me.


(Yes, I own a single-chip DLP. I have measured and analyzed it in every imaginable way and learned a lot about it.)
 

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David,


I agree with Grant that this is not a fatal design flaw for most people. Every display technology have some shortcomings, and people have to research different technologies well to make the best purchase for themselves.


I have a NEC LT150 and I've seen rainbows on one movie, but haven't noticed them otherwise and at the price point it is not an issue.


I've seen the Sharp Z9000 and even though I could see slight rainbows when I shake my head violently, the same happens with my computer monitor with B&W patterns.


The best choice is to research well to shop wisely. The electronics manufacturers are evolving their products constantly. And for competition's sake they will be making the most competitive product that they can, if not perfect for all home theater customers.


-Dean.
 

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Discussion Starter #7
In fact, you are all correct, and in terms of LCD, it is also a defective technology. To have a dead pixels is just ridiculous. I said this in my mini-impression of the Sony 11HT


The problem with DILA, however, is not so much the image, as opposed to the mechanics (ie. heat from xenon..etc..etc..) I don't think DILA has any truly inherent flaws (other than what some may consider not absolute black levels), in its image.


I guess I am angry, more for the fact that I consider DLP to be the middle of the road between LCD and DILA, and something that I would like to get in the end. It's colours are getting better and its contrast is getting better to an almost amazing degree. But the rainbow is always a deal buster.


You all missed my point though, about the cost of the single chip DLPs I was discussing. The marantz, and dwin, and seleco DLPS that are going to come out, with the same speed colour wheel as the Sharp, are most likely going to have at least some level of perceived rainbow effect. NOw, these are going to be VERY expensive. To make an analogy to a car...you would expect, and would would accept that say, a toyota corolla would be little bumpy and noisy on the highway, but if you got the same thing out of your brand spanking new Mercedes S600, would you not be disappointed? Car reviewers do take into cosideration the cost of the car, and its class, when reviewing. The little things that are neglected or trivial when reviewing economy cars can be the bains of luxury cars if not addressed. Fit and finish, trim, etc..etc...

I believe that the rainbow effect, and I guess than the colour wheels at their present speed, represent this in the upper end single chip DLPs.


When 3 chip DLP's come into the price range, I am sure I will jump the gun.


CRT: Sure I would love one, but I could never, ever convince my father to either install, pay for, or sit under one.


Screen Door IS an inherint flaw of LCD technology, as is dead pixels. The rainbow effect IS an inherint flaw in SINGLE CHIP DLP, and DILA and CRT have their own.


Depending on the price you pay, these may be a non -issue, or a deal breaker.


THAT, my friends, was the point of my rant. Geez, for 2000 bucks I would've bought and LT150 and put it in my bedroom, rainbows and all. For 15,000CDN for the Sharp, or the Marantz, or Seleco? I dont' think I would put them in my theatre room. If they were 3 chippers, the story is completely different.
 

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Discussion Starter #8
I will pray to the home theater gods to release a 3 chip DLP within the 10K price point. I think that will put a halt to my ranting...


Please, again, note, this was not against DLP as a technology, but single chip DLP as a way of implementing the DMD technology.
 

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Just want to toss in here that I definitely do consider dead pixels on an LCD projector (or laptop screen, etc., for that matter) to be a defect.


Completely off topic...I bought a Compaq iPaq Pocket PC last year. It was the first PDA to utilize a reflective color screen (great visibility outdoors in direct sunlight). Now, just about all PDA makers are using this type of screen. The problem is that dust particles can accumulate between the reflective screen and the touch screen overlay. My iPaq has tons of dust. This is not something that can be cleaned by the end user. As I said, nearly all PDA makers (certainly all new Pocket PC makers) are using this screen now, but I don't believe that anyone has solved this dust problem. This is a defect which the manufacturers have chosen to "live with" (or, more accurately, make the consumers live with) because of the other benefits that this technology offers.


Scott
 

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David,


The part of your arguement that I agree with is that TI should have advanced more quickly with their technology.


When I first saw a DLP FPTV years ago it totally blew away all of the LCD FPTVs of the day. At VGA resolution it matched the LCD models, but the DLP FPTVs didn't have the image blurring issues, had visibly better contrast, and smaller pixel gap.


Moreover the single-chip design looked like it could be inexpensively built.


At that time of 7-20K digital FPTVs, the new DLP design promised to come out with a sub $3K model, and later SVGA designs at the same price point.


I expected DLP to literally take over the higher priced CRT dominated market with a couple years, especially with DLP RPTV designs.


But instead TI kept with the VGA chip for years, and priced DLP FPTV models at or more costly than LCD counterparts.


Soon LCD started improving their designs with less persistance blurring, and higher resolution designs, some with with offset pixels to avoid screen door. And at the same price point as the now lagging VGA DLP FPTVs.


Eventually, the DLP FPTVs went to SVGA and finally XGA, and dropped in price. And recently they finally released DLP RPTVs, but at a higher price than higher-end FPTVs.


And also TI decided to hold back their 1280 X 1024 DLP chips long used in E-Cinema FPTVs, and no one has come out with a sub $15K 3-chip DLP FPTV despite the fact that a design would only cost a bit more than the current color wheel models.


But despite these marketing-derived shortcomings I think that the current DLP offerings are fairly competitive, despite the fact that TI and the manufacturers should have raised the bar rather than just matching it.


As far as the car analogy goes, the rainbows are like a car which has audible tire noise on certain roads, and certainly when you get beyond the lower priced models, such flaws should be reduced.


But they have been with the new faster/multi-segment color wheel DLP FPTVs.


It's like having that luxury car and still being able to hear tire noise on some road surfaces, but now you have to roll down the windows and stick you head out to discern them.


I consider the Z9000 fully competitive with the best of the digital FPTV out now in picture quality.


Even with 10% of the people bothered by seeing rainbows on a FPTV like the LT150 (I'm not one of them), those who are still bothered with rainbows on a new DLP FPTV like the Z9000 have to be closer to 1% of viewers, because they are so very hard to see.


While I'd love to see sub-$15K 3-chip 1280 X 1024 DLP FPTVs, I don't think that we will see them until new LCD and LCOS designs raise the bar again and DLP has to catch up once more.


After I saw the Z9000 I thought immediately thought of a friend of mine's father who has been watching the evolution of digital FPTVs for years to find one with great image quality, that is quiet, with a reasonable price, and has simple setup and operational use. And I thought that the Z9000 was a good enough match to recommend it to him as a replacement for his older CRT based RPTV.


I actually consider longer bulb life, and cheaper bulb cost to be far more of a flaw now than rainbows are with the newer DLP models.


-Dean.
 

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I do consider the rainbow a defect. I bought the Dwin DLP which when i demoed did not have any rainbow artifacts. Of course when I got it home, they were all over the place. The difference between the screen door effect and rainbows is that the screen door is always there. The rainbows come and go and become a huge distraction. I could live with the rainbow if it was always there, but the constant bombardment can drive you crazy.


To me the best comparision is to compare cheap RPTV with alot of scan lines and a current Pioneer Elite RPTV. If you compare the two, the cheapie looks like crap due to the scan lines. However, watch tv long enough on the cheapie RPTV and you will eventually forget they are there. The eyes and brain eventually takes them out of the picture. At least that is true for me. My friend got a Mits rptv and the obvious scan lines suck. My first comment at least to myself was how could anyone watch this set. However, after watching for a couple of ours, you forgot about them.


Now on the other hand, if you are watching on a Pioneer elite, and all of the sudden the scans lines started fluctuating so their is no space between them and then suddenly their is alot of space between them, I think it would drive most people crazy.


If the screen door is always there, than that is part of the techology, if the rainbows come and go then its a defect. If you ask the guys who make LCDs, they would tell you that the screen door is supposed to be there. You might not like it, but its there. The DLP guys wont say the same. All they say is that sure it exists, most people dont see it, but they cant do anything about it.


Neither the bulb price on the Dila nor the noise are defects either. We all know that the bulbs are expensive and the noise of the Dila is always loud. Now if it was loud one day and quiet the other then that would be a defect.


After spending 10K, i dont expect perfection, but I do expect it to work correctly.
 

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Discussion Starter #12
Humey,

That is similar to my sentiments.


The Sharp 9000 looks like a real winner, but I have a large screen and I am close to it...there will be head movement, there will be eye movement. If I watch a black and white movie, scene, or end credits...or high contrast scene, am I gonna see the rainbows?


If someone could say definitely not, I would start saving now. However, it is STILL there. And this is a unit that was trying to repair the problem.


Dean, for the analogy of the luxury car, there is a big difference. If I do the same thing in both the luxury car and the econobox and hear the same noise...even occasionaly....when driving without the window down, without trying to hear it...then it is a problem. I feel that that is the issue with the newer projectors. They do a great job, I am sure, but for those who are sensitive to it, we dont' have to go to the extreme to see the rainbows.


I have never looked for rainbows. Teh first time I saw a DLP at Bay Bloor Radio, I didn't even know what the rainbow really was, only knew that it existed. We watched T2: Judgement Day on a 100" screen, I was about 12 feet back. We started watching the beginning battle scene. It is dark with bright explosions and ships...etc...I wasn't turning my head ridiculously, I wasn't spinning my eyes in my sockets at a drastic level. I simply scanned from one side of the action to the other, and was greated with a rather distrubing flash of rainbows.


The same thing happened when watching gladiator on the HT200, non DM. With the lights in the room on, I couldn't see the rainbow at all, but in proper viewing conditions, they were everywhere, without any attempt to look for them (this is related to the contrast aspect of the rainbow effect, because with lights on, contrast was lower.)


I have yet to see the Sharp 9000, as no one has it in Toronto yet that I know of. However, I would like to say two things about the Sharp.

1st, I dont' believe that it is the colour wheel alone that is reducing the rainbow, it is the pathetically low lumen level that is helping it out. The rainbow effect, from what we know, is drastically altered by the level of the contrast in the scene. Now, the Sharp may have high contrast, but what is it's peak brightness? I am sure if this projector where 1500 lumens, the rainbow would be more prevelant than it is now....


Furthermore, I also believe that it's high contrast, even though others have debated my opinion, is due, as well, to this low lumen output. It has a much lower absolute black level than other non dark chip high lumen DLP's.
 

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DLP rainbows don't come and go. They're always, always there, presented with the same source material and the same relative motion of your eyes. They are not a transient defect. They are an inherent part of the imaging system.


The part I still don't fully understand is why there's not a 3-chip home DLP in a reasonable price point. I think I can guess the answer, though. The profit margin on these projectors is so outrageously high with one chip, and people continue to buy them. Why put three more expensive components into the machine (two more DMD's and the color separation/combination optics) when people will shell out the bucks for one and you get to keep the very high profit?


Maybe with the advent of projectors like the Hitachi 5500 that are 3-chip LCOS units at reasonable prices, TI and its manufacturers will start to feel some competition.
 

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Exactly right Mike, Why should they, is the answer. TI and all of the other DLP manufactures could fix the rainbow problems, and alot of other problems the DLP/LCD's have today............. but...... WHY should they? There making too much $$ on selling the same products, (with minor improvements) year after year. The car business is the same, they could come out with whats going to be on the 2009 year cars now.... but why should they? they have 8 years of minor improvements to sell to people..

just my .02 cents
 

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Discussion Starter #15
And one other common thing I don't like..especially when dealing with newbies, is that some older members say, when comparing projectors, that "this is has rainbows while this one doesn't". This is a fallacy and a misnomer. It should be stated that one projector has significantly less, or not significantly noticeable rainbow, but never should one say that there is NO rainbow. As I have said, there is really no way for us to objectively say that in the context of Single Chip DLPS.
 

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I went with LCD (Boxlight 38T) precisely because both spouse and I are rainbow sensitive. In doing so, I did my homework courtesy of this very knowledgable and generous group and learned the rules of thumb which make screen door a non issue (viewing distance minimum = 2 X screen width), combined the projector with a Grayhawk to bring contrast/blacks into the acceptable range, calibrated carefully and purchased from Boxlight because they guarantee against dead pixels for 3 years.


The result has been EXTREMELY satisfying. About the only thing my setup could use is a better scaler (I have QSE now) which I'll probably get next year.


This setup beats the heck out of any CRT that is remotely in its price range and has image/color depth and dynamics which you never get tired of. It is far better than the RPTV that it replaced.


The best news is when I first started looking at FPTV two years ago, it was downright primitive compared to this setup. I am confident 2-3 more years will yield another quantum leap in quality for similar or lower prices.


But right now today, there is an FPTV for everyone, rainbow sensitive or not, starting at around $2K. That's pretty amazing when you think my first exposure to serious HT was a G90/Faroudja combo with a price tag approacking $90K.


The only thing that is more fun than watching movies these days is watching FPTV technology leap forward and kibitzing about it with you all.


Dan
 

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complete non-starter. The rainbow flashes that occur whenever you move your head or eyes is a big distraction. But it's not the rainbows that kills DLP for me-- it's the ever escalating eye strain& eye fatigue that comes up within a few minutes of DLP watching.


It makes sitting through a 2 hour movie exhausting. LCD however, does not give me the same problem at all. My eye's do not fatigue nearly as much.


I would love to get into the DLP technology, because it seems to have all the right stuff--- but the harsh reality to my eyes is that DLP is unwatchable. Whether it's a $4000 Projector or a $10,000 DLP.


LCD has noticeable screen door, and I sometimes become aware of it, but because it is always there, it doesn't bother me as much. To my eyes, screen door is much easier to forgive because I can ignore the technology and just watch a movie--- which is kind of the point of all of this: actually enjoying a movie.


I wish I could ignore DLP induced eyestrain and rainbows--- but I cannot. If others can, then that's great, but for those of us that cannot, DLP is a practically useless.
 

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David,


I understand exactly what you are saying about Rainbows and DLPs. Yamaha came out with an excellent DLP proj with good color and black level and forgot to use the latest color wheel.


When TI developed the 1280x720 chip they should of also fixed the rainbow problem completely for these expensive projectors.


As for LCD, unless you are super close to the screen, the new (2 year old) 1366x768 panels do NOT suffer from a screen door effect. Why people continue to bring up screen door with these projectors is beyond me. Black level still suffers, but currently DLPs are the only Dig PJ which are better. As for dead pixels, make sure you can try before you buy.


DLP for HT will rule if they could just fix those damn rainbows.


Big tube CRTs don't have any flaws. But I don't have the knowledge to keep one running correctly.


William
 

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Great, another DLP bashing thread over "Rainbows" IT is SOOOO overdone:rolleyes:


Oh well, guess I'm just glad I, OR ANYONE I know can't see em while we ENJOY ourselves. Sometimes it seems that people just ring there hands over every little "defect" in the PQ.


DWIN Transvision and bliss........


Sorry you can't enjoy them.


GigEm
 

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Discussion Starter #20
Hehehe...how long have you been lurking here....I haven't seen such a thread in a LONG time...so you must've been here for a LOT longer than I have, despite your 40 post count.


Well, yeah, I guess you can be happy you have an inferiour visual acquity system within your head.


That is not the point. I am just expressing my dissapointment at the higher end DLP's, which you happen to have the money to afford, and which goes along with your said visual apptitude.


You, my friend, fit into exactly the category of people that I dislike.

"I don't see it, so it isn't a problem." This is no world crisis or anything, but this mentality has been seen many times before.


Please, please, read these "not another threads" before commenting.
 
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