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Discussion Starter · #1 ·
Hi all,


I own a Davis DLX650 clone (XGA DLP) which Thumper performed some mods on (see this thread ). I also took advantage of the Dell deal on the LT-150. So I invited a fellow AVS member over, and we did a comparison.


I'd just like to state up front that I'm *not* unbiased. I had already agreed to sell my LT150, so I wanted my Davis to look better, or at least close, to the 150.


So, disclaimer out of the way, we fired up both projectors. (The Davis has a buffer box which makes it easy to split the output of my GeForce 2 HTPC.) When we first started doing the comparison, the 150 was very impressive. (FYI, I turned the clear section of the color wheel off on the 150, and used "Natural 1" as the gamma.) We would pause, and A/B them, and the 150 image jumped off the screen. The Davis image looked dull and "dirty".


My friend suggested that we calibrate both projectors with Avia. I had just done some quick stuff by eye. So, we went through Avia, and got both projectors adjusted much better. We then played some bright scenes from Elmo in Grouchland. The 150 definitely had more saturated colors. But the Davis I felt looked more filmlike. It was softer - the 150 looked harsh. The 150 was probably oversaturated - I think with more tweaking it could have been improved. So the colors of the 150 were more saturated and brighter, but the overall picture of my Davis was still quite good, I could argue it was comparable.


We then put in the Matrix, to watch some dark scenes. It was in these dark scenes in the past that I thought my Davis could have been improved. It had great black levels, but I couldn't seem to see as much shadow detail as I expected. Well, I guess I didn't have it calibrated well, because now the Davis actually looked quite good. A/B'ing the two, the Davis definitely had better blacks and better shadow detail. My friend was quite impressed with the blacks of the Davis. It was here that we noticed that the 150 was quite blue. Blacks were pretty blue. I started to think that where I had thought in bright scenes that my Davis looked "dirty" (yellowish), it was really that the 150 was just bluer. Now that we were aware of the blue from the 150, we seemed to agree that Davis probably had the more accurate color (i.e. 6500). Now, the 150 has lots of color controls, it has a color temperature (which didn't really seem to do much) and also individual brightness/contrast controls for each R/G/B. I didn't tweak those individual controls any more - I imagine the blues of the 150 could be reduced.


We also watched some of Apollo 13. Once again, the 150 was quite blue, and the Davis looked pretty good.


We also did a gross brightness comparison, by shooting them both on the screen at once. One image was a foot higher than the other. In my opinion, the brightness was about equivalent. Well, the 150 was brighter, but it wasn't an order of magnitude. (I had previously compared my projector to a 1000 lumen LCD, and I couldn't even see my output next to the LCD's output. This difference wasn't nearly that much this time.)


So, my summary. The 150 seemed to have almost *too* much color. Probably sub-optimal calibration, it was a bit harsh. But I have to be fair. Even though I say the 150 looked "harsh", we really only felt that way on A/B's of paused frames. Watching moving video, the 150 definitely looked fantastic... Next point - I'm not sure if it was the bluer color temperature or the contrast ratio, but the white on the 150 seemed brighter and cleaner than the Davis. Probably if the 150 had the proper color temperature, it would be closer, but I'd think the contrast ratio of the 150 would still make the difference. As far as black levels go, my Davis definitely had better blacks (thanks Thumper!). There was also more shadow detail on the Davis.


Now, I imagine that *both* projectors could use a specific, custom gamma curve. You could kindof get a sense of the heights of performance to which they could both climb, if perfectly calibrated/adjusted.


There you have it. I was happy to be able to conclude that I could keep my Davis, and the buyer of my 150 will be happy to hear I am not renegging on my deal... http://www.avsforum.com/ubb/smile.gif


I just hope that I never have to put my Thumperized Davis against a Thumperized 150!!! http://www.avsforum.com/ubb/biggrin.gif


Mike



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Mike,


I've never seen a Thumper modded projector or the Davis 650 perform. But many of your observations about the LT150 picture are spot on to what I'm observing now after about 15 hours of viewing.


Bob Wood


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[This message has been edited by RobertWood (edited 08-12-2001).]
 

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Discussion Starter · #3 ·

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Discussion Starter · #5 ·
Well, with the impressive resumes of the various Marks on this forum, I'll take it as a compliment... http://www.avsforum.com/ubb/smile.gif


Mike



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The only thing I think I'm seeing differently is a yellowish cast to the 150 image. But I'm going to take another look now to be sure if that's what I'm actually seeing.

I used to always be splitting the signal to my Sony monitor (set to D6500) and that always gave me a better perspective when comparing color. When I switched to a dedicated HTPC I stopped splitting the signal. Need to get that back again.


Bob


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[This message has been edited by RobertWood (edited 08-12-2001).]
 

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I was the friend present at the shootout and Mike summarizes our observations quite well.


When I got home and looked at my Sony 10HT, I would have to say that the thumperized Davis had better blacks than the 10HT, but the 10HT was better than the LT150. Of course, going by memory is a terrible way to do comparisons, so take that with a grain of salt.


I think in the right hands (i.e., someone with color calibration tools) the LT-150 could look phenomenal. Out of the box, and using Avia for brightness/contrast/hue/saturation adjustments, I would say that the projector isn't ready for critical home theater viewing, but would be more than welcome in any other room.


The projector is very small and very quiet. It's not much bigger than a portable CD player and the Davis in a hushbox was much louder than the LT-150. For $1600, I wouldn't hesitate to throw one in my bedroom.



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Brian
 

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Discussion Starter · #9 ·
I just wanted to point out that Brian's 10HT is a very tweaked and calibrated 10HT, including a colored light filter in front of the lens. It looks *very* nice. So when he says that he thought the 150's blacks weren't as good as his Sony, that does *no*t mean that the 150's blacks were really a bright gray... http://www.avsforum.com/ubb/smile.gif


Mike



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Very interesting comparison.

I would enjoy reading more details about those black levels

between the 10Ht and LT150.


Also the difference between pixel size/visibility on the 3 pjs

___________________

"So when he says that he thought the 150's blacks weren't as good as his Sony, that does *no*t mean that

the 150's blacks were really a bright gray... "

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Mike,

Could you expand your statement with more details?


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"the Davis in a hushbox was much louder than the LT-150."

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That Davis must be very loud!



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Jim Story

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Discussion Starter · #11 ·
Quote:
Originally posted by Jim Story:
Very interesting comparison.

Also the difference between pixel size/visibility on the 3 pjs
We were sitting about 12 feet from a 4' x 7.5' image. No screen door was noticeable/bothersome, though we didn't really look for it. I know screen door doesn't bother me unless it's really bad, so as long as nothing jumps out at me, it passes my test. But tonight, I can try another A/B, to compare the fill ratios of the 2 pjs.

Quote:


"So when he says that he thought the 150's blacks weren't as good as his Sony, that does *no*t mean that

the 150's blacks were really a bright gray... "

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Mike,

Could you expand your statement with more details?
Just that everyone on this forum makes fun of the black level of the 10HT. The 1st time I saw it, it was not nearly the issue (to me) that others made it out to be. (Of course I don't come from a CRT background.) Also, Brian's 10HT is super-tweaked, in that by using a color filter to reduce the output from one of the (strongest) colors, he's able to boost the brightness on all the colors, at the same time reducing black level at the low end. (Actually, I'm not sure if black level is reduced, or just that the contrast level is increased.)

Quote:


"the Davis in a hushbox was much louder than the LT-150."

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That Davis must be very loud!
Well, the 150 was pretty quiet, but I'm not sure we really did a good job of localizing noise. I also had my HTPC nearby, not protected by a glass door yet. You should also keep in mind that I did not have my sound system hooked up, so we were sitting in complete silence, besides the noise from the equipment. So I'm not really 100% sure where the various noises came from.


Mike




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Discussion Starter · #12 ·
Just wait until I get the protocols from Davis for custom gamma tables! http://www.avsforum.com/ubb/smile.gif OK, I'm not really confident that I will, but you can always hope, right? I really don't want to have to reverse engineer their firmware and hack the gamma tables that way! (Because I'll probably blow up my projector in the process of getting nowhere...)


Mike



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Discussion Starter · #14 ·
Yes, my gamma correction program had no effect on the overlay. That's why I'm trying to go direct to the Davis.


I don't think Matt works at Chatani anymore. But don't worry, I have a source on the inside... http://www.avsforum.com/ubb/wink.gif Also, I'm doing something on my own, don't know if it will work yet.


Mike



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Discussion Starter · #17 ·
BTW, I checked the noise level again last night, and it turns out the the 150 is definitely louder than my Davis in the hushbox. So our initial impressions were not correct...


Also, as far as screen door, I went within a foot of the screen, so that I can see it, and I would say they were about equivalent. Definitely very good. Just a thin line on the edges, and a very faint circle in the middle at the pivot point of each mirror.


Mike



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