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Discussion Starter · #1 ·
Hi,


I just received my JVC SX-21 from AVS and Jason Turk. They have been great. I am a CRT convert so the digital projectors are new to me.


I have a question about light output. When there is no signal to the SX-21, there still is light being projected out the lens bright enough that you could not look into the lens without being blinded. Why? do I have something set up wrong?


When no signal is present on my CRT there is nothing being projected, no light, the tubes are dark. How do I fix this? Can I fix this?


Thanks in advance for the help.


Jeff
 

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Hi Jeff,


On my SX21 I get bluescreen with no incoming signal. It's quite bright. It's normal.


You can use the "Hide" command to block the bright light. Although you'll still see some light output, it won't blind you. :)


Enjoy!


- Tom
 

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Discussion Starter · #3 ·
Hi Tom,


Thanks for the reply. I am not talking about the blue screen. I am talking about when there is no blue screen but the projector is still on. There seems to be quite a bit of light being projected through the lens making the screen look a shade of grey. The light being projected is bright enough to hurt your eyes if you look directly into the lens.


Is this normal? Why is there light from the projector if there is no signal?


Sorry for the newbe questions but I am used to a CRT. On a CRT when there is no signal the tubes are off and there is no light at all so the room is dark.


This situation is also noticeable at the end of a movie when the credits are rolling by on a black background. The black background isn't really black due to some light being projected when it shouldn't be. I tried reducing the brightness to the point that the credits disapear but it does not affect the amount of light on the background. In other words, I should be able to turn the brightness down to the point the projector lamp is off right?


Hope that made sense.


Jeff
 

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Jeff,


I'm going to answer this assuming that it is a real question (CRT people would love to bait some people here like this). I think most would agree that the biggest weakness of the SX21 vs CRT is that lower contrast ratio. That is why that contrast ratio spec is such a big deal on digital projectors, why there are so many posts around here about contrast ratio issues, and why so many digital projector engineers spend long hours trying to make the contrast raitos better. JVC claims 800:1 on/off CR, meaning that the lowest light level will be 1/800th the highest light level. In actuality I think it is worse than that after calibration (even though I measured mine out of the box as higher than that).


Changing the brightness will not effect the lowest light output that the projector is capable of. If you want to move the whole range down you should try a neutral density filter or darker screen. The filters are a lot cheaper to experiment with.


I hope that you can find some way to make this work for you, but you won't see no light for black from the SX21.


If you want to go with digital, but it turns out the contrast ratio is extremely important to you, then you may want to look into something like the Sharp 12k, Marantz S3, or similar. Those will probably approach 3000:1 real world CR. If you do decide that you may want to switch, please become educated on the weaknesses of those (mostly rainbows). None of these front projectors is without their weaknesses vs the others.


--Darin
 

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I would agree with Darin. I notice the same thing with my G-15. I don't know for sure, but I wonder if it is one of the reasons for the halo of light which appears around the image on the D-ILA. This can't help but cast light on the black areas of the image and contribute to some loss of contrast. It must have something to do with the fact that there is a 420W xenon arc light bulb which is always on. I'm sure they are working on ways to improve that, but it must be a difficult engineering problem.

Larry
 

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Discussion Starter · #6 ·
Hi Darin,


I appreciate the informative reply. Yes this is a real question I had and wasn't trying to bait the digital pj owners. I did not know that the light on a digital projector is reduced by the contrast ratio but always on. I thought at some points the light would actually be off.


Before I purchased the SX-21 I did do a fair amount of research and did understand that the contrast ratio was an issue with most digital projectors as compared to my old Barco 1208s. I didn't want to chance a DLP due to the headache issues and rainbow. I would probably end up being one of the few that would be sensitive to this. LCD's appeared to have more of a contrast issue, so I saw more positive aspects than negative aspects and bought the SX-21.


Overall I am very pleased with the picture quality. The bright picture is unbelievable. I can literally watch the picture with the lights on or the drapes open (if I wanted to). I could never see the picture on the Barco in those conditions. The picture is much sharper than I could get with the Barco with WAY less effort and set up. Colors are similar to the Barco although I can get A LOT more saturation on the SX-21. And of course the pj is 13lbs versus the 250lbs to lift to the ceiling mount.


The contrast ratio really doesn't bother me during regular picture scenes. It bugs me a little when it is a really dark scene towards the edges of the frame. I have a Stewart Studio Tek 130 fixed mount screen that has a 4" black frame around it. A dark scene against the black frame is when it is noticeable.


With all of the positive things I gained and contrast only bothering me sometimes I think I made a big improvement over the Barco 1208s.


Darin, you mentioned light filters. Are there any that you use or recommend trying?


I also wanted to mention that I set my inputs to the projector to the JVC recommended specs posted on another thread, (dot clock, front porch, back porch, etc) and was stunned. The picture was beautiful before the settings but after the settings the picture was stunning, breathtaking, jaw dropping, unbelievable. WHAT A DIFFERANCE! This is the closest I have seen a DVD look like HDTV. I was watching an old 1972 Charles Bronson flick and could not get over how life like the picture was. Imagine how good a newer better-transferred DVD would look. I can't wait to try it!


I would recommend using these settings on the SX-21 for anybody who has the ability to change them.


Please let me know about your light filter recommendations.


Jeff
 

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Quote:
Originally posted by jak
Darin, you mentioned light filters. Are there any that you use or recommend trying?
Jeff,


I haven't tried any on the SX21, yet. I've found that adorama.com is a good source for filters. Here is a neutral pack that would probably be good to try. It has 3 different levels of filtering. If you try them and find that you like one you could always buy a glass filter for more.


The fact that you can watch with the lights on tells me that it might be a little brighter than you need with the lights off. Then a neutral density filter that you put on and take off is a good way to keep the bright images at times and also be able to move the whole light range down for better black levels for some material.


Another way to go is that get a color correcting filter. The difference here is that you can actually increase the contrast ratio range by using one of these and recalibrating. I haven't tried any on the SX21 yet, but someone recommended about a CC10R. This would reduce the red by 10% and since it is the weakest color this allows turning the blue and green up and still having balanced colors. William Phelps said that the calibrated CR went up about 100 points with a filter like this and ended up at 550:1. Although in theory these filters shouldn't decrease brightness, my experience is that they do (they filter some blue and green also).

Here is one like I generally use for testing and used on an M20 D-ILA that I had. They can be cut to fit. If you find one that you like and want a glass one, you can always upgrade.
Quote:
I also wanted to mention that I set my inputs to the projector to the JVC recommended specs posted on another thread, (dot clock, front porch, back porch, etc) and was stunned. The picture was beautiful before the settings but after the settings the picture was stunning, breathtaking, jaw dropping, unbelievable. WHAT A DIFFERANCE! This is the closest I have seen a DVD look like HDTV.
Are you referring to the numbers in this post? I'm assuming you set these in Powerstrip in your PC. Is that correct? Or was this with a D1 DVI player (I don't remember what the custom settings have as options).


Thanks,

Darin
 

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Discussion Starter · #8 ·
Thanks Darin, I will check out the filters and give them a try. They seem very reasonable in price to experiment with. To take them on and off is a plus. On thing I am looking forward to is watching is NFL games. With the Barco, watching football in the dark wasn't that great and didn't seem right esspecially when you have a group of people over. Being able to have a real bright picture with some lights on is a plus for those occasions.


Yes, those are the settings I was reffering to. They made a big difference even to the untrained eye like mine. I have a Rock scaler that is able to do custom settings and that is how I did it. Iwas able to duplicate each of those settings exactly. I am using power strip on my PC which is also attached to the projector but I haven't had a chance to tweak that yet.


I read a lot on this forum (don't post a lot as you can see) and William Phelps name comes up a lot. Has he done a lot of testing and such with digital projectors? Where can I read more on his PJ experiences?


Thanks

Jeff
 

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Jeff, I am assuming that you are not yet using an aftermarket anamorphic lens with the projector yet? This can improve the picture quality from the projector in several ways. First, you get added brightness (I measured an increase of around 17%). Second you also increase the resolution by using the full panel when projecting a 16:9 image instead of masking off part of the panel. Third, you will reduce the Halo, or overspray of light that comes off the projector and washes out the black level thereby increasing contrast.


If you are not using the lens, you can enhance the contrast and make your blacks appear darker by masking off the light that comes out of the projector with a cardboard cut out to 16:9. This will reduce the amount of light that spills onto the screen and your ceiling, washing out the image. It is a simple, inexpensive trick that works well for the SX21.


One other thing. I don't know if you have the Rock or your HTPC hooked up via DVI, but if not, when you do you will be quite pleased at the improvement in the picture. I believe the Gamma for the DVI port on the SX21 is better than the other inputs and the black level is deeper for it as well.
 

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Discussion Starter · #10 ·
Hi Free,


I have a panamorph lens ordered with Jason at AVS, which should help. I don't have a HTCP I was referring to a standard computer, which I use for gaming or large screen surfing the net. The Rock does not have a DVI output so I am using the RGBHV input on PC2. I would like to try the DVI input sometime but that would take an upgrade to my computer or a new DVD player. I currently use a Sony 9000ES player it does real good for me. (I know it has the chroma bug)


The cardboard cutout is a great idea. I am excited about getting the panamorph; I have a lot of light spill onto the ceiling and wall above and below the screen and agree that is definitely taking away from the perception of black.


The projector is real impressive to me now. With a little more tweaking and the advice from all the great people here the projector should be awesome.


Thanks

Jeff
 

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Jeff


This is a delightful thread!!!!!!


You and i are soooo similar.


Hard core CRTers for many years. I had a line doubled Sony 1252 that i am now donating to my son's school (god help them).


We both bougfht Stewart Studiotek 130 screens for our CRTs. Mine is a 16x9 100" effort.


We both bought JVC SX21 digital Pj's


Now here is where we differ :)


I searched out a used ISCOII anamorphic lens from fellow member Noah Katz. You get increased brighness and resolution. totally recommended for the SX21.


I'm also contemplating the Vutek Silverstar screen.


Fun isn't it?


Rob
 

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Discussion Starter · #12 ·
Robert,


I can't wait to get my lens. It sounds like you like the addition of the anamorphic lens on your system.


My screen is almost the same size as yours at 106" diagonal. I am going to keep the Studio Tek 130 for now and experiment with some neutral density filters instead. That way if I want a real bright picture for sports I can remove the filter and would still have the higher output of the Studio Tek 130.


I followed your threads and made the decision to buy the JVC right around the same time you did.


Jeff
 

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I tried these timings:


> Full 1400 x 1050 resolution

> Recommended timing.

>

> Pixel clock :115.200MHz

> Horizontal Frequency : 64.000kHz

> Vertical Frequency : 59.981Hz

> Horizontal total time :1800[pixels]

> Horizontal active time :1400[pixels]

> Horizontal front porch : 40[pixels]

> Horizontal sync width : 112[pixels]

> Horizontal back porch : 248[pixels]

> Vertical total time :1067[Lines]

> Vertical active time :1050[Lines]

> Vertical front porch : 1[Lines]

> Vertical sync width : 3[Lines]

> Vertical back porch : 13[Lines]

>


over DVI and the projector would go in and out of sync. I then switched to analog and it worked fine. Does anybody know the correct values for pixel perfect mapping over DVI?


Jeff,


William Phelps is pretty much the guy for professionally calibrating DILAs. I think he might be the guy for CRTs, also. He has been doing Faroudja's projectors for shows for a while and from what I understand a lot of the stuff in Hollywood. I think he posts under "wm" here.


I think William might be the only person offering professional calibrations on the SX21. Hopefully we'll see a Dilard version for it, also. Mine looks pretty good. I'm not sure how much calibration it needs. However, I do notice some fixed-pattern-noise that it would be nice to improve. I don't know if anybody else noticed it when I had people from here over last night, though. I've gotten pretty picky about looking for the little things :)


--Darin
 

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Darin,


When you create the custom resolution in Powerstrip, try entering only the 1400x1050 pixel dimensions and vertical refresh rate (60Hz). Leave the rest of the timings (porch, sync width, etc.) at the default settings Powerstrip assigns. I did this and achieved 1:1 via DVI with a Radeon 7500 with no difficulty.
 

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Darin, those are the settings I use and they should work fine? You might have to create a custom monitor INF file and load that manually. Don't ask me how to do it because I stumbled through the process and am not really sure how I did it. HTPC's are not really my Forte :)
 

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On the SX21 and CC filters: they do work, but you have to completely recalibrate the projector to take advantage of them. I find that most, but not all, benefit from a red filter, but it depends on the projector.


William
 

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WM what else is provided in your service of tweaking the SX21 other than using a color filter and Calibration? Is there some internal hardware adjustments?


Also, how long would one expect to be without their projector if they sent it to you for calibration.


Thanks,
 

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William,


How do you feel about fixed-pattern-noise on the SX21? I feel like I can see some on mine, but I'm not sure what is causing it. On my M20 D-ILA I was able to get most of the pattern out with the 8 bars adjustments in Dilard. However, on my SX21 each of the colors seems to look okay by themselves, but with white it seems like I can tell that there is a grid even from 2x screen width. I don't have bionic eyes, so I would have expected for things to smooth out by there. Maybe it has something to do with the way my panels align. From up close it almost looks like the pixels are in small groups. So, I might not be able to distinguish individual lines of pixels, but it is as if I can distinguish between the combinations of 2 lines (or so) of pixels.


I watched a movie called "Along Came a Spider" last night that stars Morgan Freeman and an actress with very light skin. He was much darker than her and his face tended to look pretty realistic to me, but on her face it was like there was always a digital grid. I was using 1:1 mapping from a PC and this was an HD version.


I'm not saying that things didn't look good (others thought the SX21 looked great and I think so to with some stuff), but not up to what I remember seeing on the SX21 at CEDIA. I'm not sure if I saw any bright whites during that demo, though.


Do you think there are any adjustments you could make to help the smoothness? Any other advice would be welcome, also.


Thanks,

Darin
 

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"(dot clock, front porch, back porch, etc) and was stunned. The picture was beautiful before the settings but after the settings the picture was stunning, breathtaking, jaw dropping, unbelievable. WHAT A DIFFERANCE! "


Are these adjustments required on DLP's? Is it because a HTPC is being used?


Thanks
 
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