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  1. #1
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    Oldbie nees advice on DLP

    I picked up (um, had delivered, actually) the LG 62SX4d DLP about two weeks ago and I must say I am very impressed. Of course, I went from a 57" Sony 16:9 RPTV so of course, the brightness levels are a big improvement after having to be so conscientious with ambient lighting with the RPTV. I was wondering if anyone has any tips regarding DLP. I was so used to gleaning any info from the web about CRT's that I now know more than I care to about them and nothing about DLP. Gosh this stuff is fun! I have the AVIA Disk although I have not yet attempted to calibrate it. I got it out of "torch mode" and am very pleased with the black levels and color saturation. The manual lists the specs as 1280x720P - that's good right? It also has the Texas Instruments newest three chip DLP. I know with the CRT it is best to reduce the Sharpness to near zero, but that does not seem to apply with this DLP - I have it reduced to about halfway. Do ISF Techs do calibration on sets liket this? I feel quite ignorant.

  2. #2
    Forum Regular edtyct's Avatar
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    Congratulations on your new behemoth. AVIA should help you fine-tune the set, but ISF calibaration is always an option, since few TVs come anywhere close to the D6500 gray-scale temperature on professional monitors (incidentally the "D" stands for daylight, at noontime) or bother to get the color points right. The 1280x720 spec is one of the two main current high-def standards (the other being 1080i at some horizontal resolution up to 1920), though 1080p is just starting to peek its head into the door.

    The DLP that you have isn't a three-chip design, which is still reserved at this point for expensive DLP front projectors. You have the HD3 chip that Texas Instruments devised as a cost-effective alternative to its HD2+ chip. However, it boasts improved contrast. The set uses a spinning color wheel to provide color instead of the three-chip design that LCD and LCoS feature.

    Sharpess control on microdisplays usually doesn't come into play, except as a way to introduce distortion. Many of these displays can survive quite well with a setting at 0 or close to it, though some can go to the halfway point. What do you want to know?

    Ed

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    Forum Regular hermanv's Avatar
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    More DLP questions

    I had a home fire and lost my Toshiba HD Cinema Series RPTV (It was pretty good except the perenial convergence problems most CRT sets seem to have)

    I'm going to replace it with a DLP set. Probably one of the models that pose as "monitors" though they still have tuners and speakers (huh?) Like most owners I plan on an external sound system and will probably re-instate my Direct TV service so I won't use their tuner either (Why do I have to pay for this stuff? Most home theater systems do what I do, why not make a true monitor design?)

    Anyway the big question is 1080p? It seems like a good idea even though there are currently no sources of 1080p. Some have said that it makes NTSC (480i upconverted to whatever is native for the display) look worse than a 720p set but they have offered no reason why this should be true.

    Any insights?

  4. #4
    Forum Regular edtyct's Avatar
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    Sure. The reason why 480i could well look worse on a 1080p set than on a 720p set is that it has to undergo so much scaling. Sets with a native resolution of 1080p must display every signal at that format. Therefore, 480i programming must not only become progressive; it must also extrapolate enough data from its inherently limited pixel count to display at 1080p--a daunting task that is likely to show a lot of bad edges and blurry images. It's much easier for 480i to puff itself up to 720p, which is a lot less space to fill.

    A 1080p display arguably will have an advantage with high-def material, particularly on larger sets, since the scaling won't be so severe. It may permit closer viewing or create a finer, sharper look for those with large screens and fixed seating.

    Ed

  5. #5
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    EDTYCT - What a guy!

    Quote Originally Posted by edtyct
    Congratulations on your new behemoth. AVIA should help you fine-tune the set, but ISF calibaration is always an option, since few TVs come anywhere close to the D6500 gray-scale temperature on professional monitors (incidentally the "D" stands for daylight, at noontime) or bother to get the color points right. The 1280x720 spec is one of the two main current high-def standards (the other being 1080i at some horizontal resolution up to 1920), though 1080p is just starting to peek its head into the door.

    The DLP that you have isn't a three-chip design, which is still reserved at this point for expensive DLP front projectors. You have the HD3 chip that Texas Instruments devised as a cost-effective alternative to its HD2+ chip. However, it boasts improved contrast. The set uses a spinning color wheel to provide color instead of the three-chip design that LCD and LCoS feature.

    Sharpess control on microdisplays usually doesn't come into play, except as a way to introduce distortion. Many of these displays can survive quite well with a setting at 0 or close to it, though some can go to the halfway point. What do you want to know?

    Ed
    Thanks Ed, I knew I could count on you. I guess I am just looking for basic tips for a guy that is used to the sometimes spectacular but often darker than desired RPTV display. Just lay it on me baby . . . Er, I mean, please share your wise and sage knowlege in general terms. I have read many of your posts - if you get too technical, it will make my head smoke, and it's already smoldering. It's funny, a lot of people I know call me up for advice and with their a/v ht questions and I don't really know much, just from personal experience and common sense. And then, guys like you and Terrence the Terrible make us all look like neophytes - you are much nicer about it though - no disrepect T, really (yikes!)

  6. #6
    Forum Regular edtyct's Avatar
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    Hey, thanks, Hairsonfire. In general terms, you got yourself a mighty fine hunk of TV. It will do just what you seem to want it to do--that is, show up better in ambient light than a CRT will. It is also capable of better blacks than LCD, which was its original competition in the fixed-pixel RPTV sweepstakes, and arguably has a smoother look at a closer viewing distance because of how its pixels are arranged. The technology of DLP stuns me, to be honest--all those little mirrors shucking and jiving to catch or avoid light, thus creating its gray scale, and its whirling color wheel fooling the eye into thinking that all the objects on screen are simultaneous spacial creatures. In fact, given the number of sequential events that take place inside a DLP, it's a wonder that each frame looks so damned smooth. Simply ingenious.

    Anyway, once you calibrate with AVIA, you should have a picture that satisfies you for a long time to come: no convergence issues, no burning picture tubes, or etched CNN logos. I'm assuming that the color wheel hasn't given you a headache, as it does some people, or splayed little delay rainbows on your screen when you turn your head. This is really the only serious drawback to a DLP, but most people aren't affected.

    There's not much else to tell, unless you have a particular question. Just give AVIA a spin; then pop in a DVD or dial up an HD program and enjoy it. Life is good.

    Ed

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    Talking No, thank YOU!!

    Quote Originally Posted by edtyct
    Hey, thanks, Hairsonfire. In general terms, you got yourself a mighty fine hunk of TV. It will do just what you seem to want it to do--that is, show up better in ambient light than a CRT will. It is also capable of better blacks than LCD, which was its original competition in the fixed-pixel RPTV sweepstakes, and arguably has a smoother look at a closer viewing distance because of how its pixels are arranged. The technology of DLP stuns me, to be honest--all those little mirrors shucking and jiving to catch or avoid light, thus creating its gray scale, and its whirling color wheel fooling the eye into thinking that all the objects on screen are simultaneous spacial creatures. In fact, given the number of sequential events that take place inside a DLP, it's a wonder that each frame looks so damned smooth. Simply ingenious.

    Anyway, once you calibrate with AVIA, you should have a picture that satisfies you for a long time to come: no convergence issues, no burning picture tubes, or etched CNN logos. I'm assuming that the color wheel hasn't given you a headache, as it does some people, or splayed little delay rainbows on your screen when you turn your head. This is really the only serious drawback to a DLP, but most people aren't affected.

    There's not much else to tell, unless you have a particular question. Just give AVIA a spin; then pop in a DVD or dial up an HD program and enjoy it. Life is good.

    Ed
    Wow, you told me exactly what i wanted to hear! Yes, luckily, I do not seem to perceive the rainbow effect. I was actually set to buy the Sony 60 inch LCD when I came across the LG. I noticed with both sets that in a display of mostly white (The ice in a Hockey Game for example) that there seemed to be a . . . how do I describe this . . . sort of a shimmer effect. I still see that, but all things being equal (I never understood that term but it always sounds so intellectual) it is not that distracting and is a fair trade off. One thing that bothers me is the bulb life. I am not one to leave the TV on like I know a lot of folks do - but I feel like I am "using up the bulb" when I have family visiting (like right now) and we end up having the set on for eight hours at a stretch. I am a movie guy, and typically will have the set on for 90 minutes to two hours max. I feel like I should buy a new bulb now as a spare for when it fails. In any case, thanks again. This stuff is sooooo fun.

  8. #8
    Forum Regular edtyct's Avatar
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    The bulb thing's a pain in the neck, but with any luck, you won't need a new one for a couple of years. By that time, the price might come down enough to make the inconvenience mostly logistical. The shimmer that you saw on both sets in the store probably came from contrast and brightness set way too high and less than optimal viewing circumstances. I'm sure that it's gone now, if, as you said, you've relieved your set from torch mode. AVIA will cure a multitude of pre-programmed sins and might even inspire you to go further. Hey, if you decide not to enlist ISF, you can buy the LG service manual for less than $20 and a color comparator for less than $500--that is, if you decide not to spring for a full-bore color analyzer at less than $10,000. Just kidding. Most people who bother to calibrate by disk are eminently satisfied with the results. Happy holiday.

  9. #9
    Forum Regular hermanv's Avatar
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    Light sources

    Hey Ed;

    Complaints about the DLP bulb life appear in many places on the net. No one ever mentions LCD or LCOS bulb life. Don't they use virtually the same concept?

    Thanks for your answer on 480i upcoverted to 1080p. I'm sure thats mainly true, but NTSC is 525 horizontal lines. if you double that number to 1050 and just accept a small black top and bottom bar it seems that less mathmetical gymnastics are needed to just double than to change to 720p (that involves roughly 1/2 pixel interpolation). So 1 pixel effectively becomes 2 instead of 1 1/2 . Not easier and cleaner?

  10. #10
    Forum Regular edtyct's Avatar
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    If it were just a matter of increasing pixels by some mathematical factor, then on some logic the move from 480i to 1080i might seem easier. NTSC is 480 interlaced lines with overscan, and you don't want to see some of the material that's overscanned (it's more likely that a set overscans too much than too little, anyway). But doubling pixels isn't the long or the short of it. First, 480i comprises two fields of 240 alternate lines. On a progressive display these two fields have to be deinterlaced, either with some form of video deinterlacing, which is wildly complicated, or 2:3 reverse pulldown for film, which is less demanding in some ways but still subject to errors emanating from the irregular cadence in the frames. Then the reconstructed 480p frames, with their various degrees and kinds of processing artifacts--some of them barely visible on a small display--have to be upscaled further to reach a total visible 1080 progressive lines. Any imperfections in the 480i to 480p deinterlacing due to motion or judder will be magnified intensively when the set has to interpolate another 560 lines (more than the original signal contained) from the scanty data that it has to use. The picture will most certainly look soft compared to a signal that started at a higher progressive resolution like 720p, and it will most cetainly contain noise and edge discontinuities/incongruities that weren't in the original 480i fields as shown on a standard NTSC system.

    I don't know what's going on with the DLP bulbs, which work on the same principle as the LCD and LCoS ones. How those bulbs burn has a lot to do with the particular display. The DLPs might put them in more jeorpardy because of manfacturing flaws.

  11. #11
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    Talking Come on ED, I told you what happens . . .

    Quote Originally Posted by edtyct
    If it were just a matter of increasing pixels by some mathematical factor, then on some logic the move from 480i to 1080i might seem easier. NTSC is 480 interlaced lines with overscan, and you don't want to see some of the material that's overscanned (it's more likely that a set overscans too much than too little, anyway). But doubling pixels isn't the long or the short of it. First, 480i comprises two fields of 240 alternate lines. On a progressive display these two fields have to be deinterlaced, either with some form of video deinterlacing, which is wildly complicated, or 2:3 reverse pulldown for film, which is less demanding in some ways but still subject to errors emanating from the irregular cadence in the frames. Then the reconstructed 480p frames, with their various degrees and kinds of processing artifacts--some of them barely visible on a small display--have to be upscaled further to reach a total visible 1080 progressive lines. Any imperfections in the 480i to 480p deinterlacing due to motion or judder will be magnified intensively when the set has to interpolate another 560 lines (more than the original signal contained) from the scanty data that it has to use. The picture will most certainly look soft compared to a signal that started at a higher progressive resolution like 720p, and it will most cetainly contain noise and edge discontinuities/incongruities that weren't in the original 480i fields as shown on a standard NTSC system.

    I don't know what's going on with the DLP bulbs, which work on the same principle as the LCD and LCoS ones. How those bulbs burn has a lot to do with the particular display. The DLPs might put them in more jeorpardy because of manfacturing flaws.
    . . . When you get too technical . . . it HURTS MY HEAD AHHHHHHHHHH! Actually, I understand most of what you wrote . . . Except the judder part.

  12. #12
    Forum Regular hermanv's Avatar
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    Thanks again Ed:

    If I may presume to convert to moron speak: The stairsteps get twice as big, requiring that much more processing to smooth them out.

    You imply that the affordable processing might not have caught up with the 1080p scanning capabilities. For the sake of curiousity, wasn't it true that the front projection CRT sets had this many or near this many scan lines sometime back?

    A new decent (i.e. not the low end model) 720p 56" DLP can be had on the internet for about $2,000, currently the 1080p sets of the same size are hard to find below $2,700. Let me put you on the spot: are you of the opinion that a 1080p set may not be a good buy today, might it be next year?

  13. #13
    Forum Regular edtyct's Avatar
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    Last question first: 1080p is cool, and it is inevitable. Nevertheless, it doesn't have absolute value. First, not many 1080p sets can actually accept 1080p through their video inputs. The fact that no 1080p source material exists yet doesn't mean that this is an idle point; a set that can scale to 1080p but not accept already scaled 1080p is missing out--bringing me to your penultimate paragraph. Advanced deinterlacing for 1080i has not been readily available for commercial purposes. Film and video processing for 1080i thus far has been only of the rudimentary kind. The new outboard processors that can scale to 1080p with 2:3 pulldown, edge filtering, and motion detection could help smooth and sharpen 1080i on sets that scale to 1080p, especially on large screens, but the majority of them won't ever know how much. Scaling and deinterlacing are extremely delicate, artful . . . and imperfect under the best conditons. It just isn't realistic to expect a 480i ugly duckling to transform easily into a 1080p swan, but the most expensive and elaborate processing can make a difference. As 1080p becomes more popular, processing advances will trickle down to 1080p sets. This is a new frontier. Sony's new $10,000 SXRD front projector will input 1080p at 50/60 fps. Others will follow suit. But for most people with typical bank accounts, viewing preferences, and living conditions, this might not be the best year to pursue 1080p, but it ain't my call.

    The second caveat about 1080p is that not every environment will benefit from it, even when all of the conditions of the last paragraph are met. In order to actually see a 1080p resolution on a 42" display, a viewer has to be about 5 ft. away; on a 52" display about 7 ft. away; and so forth. Moreover, from that vantage, low-resolution programming scaled to 1080p could look wretched. The point is that 1080p makes the most sense on a large screen showing mainly progressive ED and HD material at a comfortable viewing distance. If you can't manage the right screen size for your seating, you might be wasting money, unless bragging rights were important, or you were willing to scale down your home theater, which might at the very least wreak havoc with your audio.

    Are you talking about RP CRT sets during the analog days? In the early 90s (?), Japan adopted an analog HD format that some people advocated for the U.S. as an interim standard. Is that what you mean? Other than that, analog CRT manufacturers used to advertise the resolution of their sets by stating the number of horizontal lines, which could make them seem better, though it really had no bearing on anything of importance. However, from the moment when CRT had achieved HD capability six years ago or so, it had a 1080i format, dividing the vertical lines into successive odd and even fields that they eye saw as a single frame. Full progressive scanning at 1080 had to await the digital, fixed-pixel displays.

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    Forum Regular hermanv's Avatar
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    Wow, your posts have helped a lot. Let's see if I have it basically right.

    If most of the newer 1080p sets can't accept a 1080p input, then buying a better outboard processor at some future date becomes problematical if not impossible. (This could be important because other than bulb life the DLP sets should last a long time)

    So anyone considering a 1080p set should probably view it with a 480i source as well as DVD to verify that the picture is at least acceptable. Otherwise real world picture performance might actually be worse or at best quite similar to the 720p DLP sets which are noticably cheaper.

    So at least for 480i sources, it seems that for maximum bang per buck, we need to find out who de-interlaces before they upconvert opposed to upconverting fields and then buy their 720p set.

    One final question before I think hard about sticking with 720p. Toshiba was on my 1080p short list, they make a "Theater Series" 56HM195 and a "Cinema Series " 56MX195. Do you know if they use the same conversion engine?

    Please pardon my (our?) shameless theft of your expertese and knowledge.

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    Forum Regular edtyct's Avatar
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    For the life of me, I can't figure out what accounts for the $300 price difference between the Cinema and Theater series. The former has an ethernet port and a PC input, but they seem to share the same "smooth picture" (wobulating) chip and all of the really important video features (like the dynamic aperture control, the TALEN engine, and the PixelPure processing). Toshiba in the past has offered a screen with better control of ambient light on its higher models; maybe they did so this time, too.

    A lot of people get big TVs home and can't believe how bad their favorite non-HD programs look. If you can satisfy yourself before you buy, you'll be doing yourself a favor. Just remember that these DLP sets were made to thrive on high-resolution material. They look forward, not backward.

  16. #16
    Forum Regular hermanv's Avatar
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    edtyct: Thanks again for your help

    I have a Toshiba 55" CRT RPTV. I use a Direct TV satellite service. I find that picture quality for 480i sources is all over the place, some is near as good as DVD, some looks like it's a homemade VCR tape and a cheap one at that.

    I don't mean the digital bandwidth assigned to the channel, those artifacts, pixellation and gray scale coarseness look quite different from basic fuzzy pictures.

    Even HD sources vary quite a lot, in many cases it seems the source material is just a small notch better than 480i. I have seen HD sources that were not as good as DVD. I assume as the technolgy improves and camera costs come down this will steadily get better. This was certainly true for NTSC, some of the old TV shows from black and white days look like todays home web cams. Others that were filmed instead taped are quite good.

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