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Discussion Starter · #1 ·
I wrote this in another post, but I really wanted to ask the question directly to those who have High Power screens as I feel like I may be missing something. How do you deal with the varying brightness in images from different seating positions? Do you just calibrate your system for the sweet spot seat or do you try to do "middle of the road" settings so that the image looks decent from all seating positions? Or is my set up just not right for High Power due to the viewing angles from my front row seats and the fact that my projector is ceiling mounted?


Thanks,


Craig


Following is my original post:



"Actually I did get my hands on some Da-Lite screen samples and taped them to my screen last night. They were High Power, Video Spectra and Matte White. From any one of my second row of seats, the high power really blew the other two away with a much brighter picture and intense colors. The video spectra was slightly brighter than the Parkland screen it was taped to and the matte white looked just like the Parkland.


The problems came from my front row seats which are about 5 feet closer and 12" lower. From the center seat the high power was much less bright than from the back row and looked about the same as the video spectra. Again, the matte white looked like the Parkland. However, if I moved to either side seat in the front row, the high power dropped off to look like the Matte White and Parkland (actually maybe even a little darker), with no apparent change in the video spectra.


So it appears that with the High Power, I would have three very different images depending if you are sitting in 1. the back row, 2. front and center, 3. front and side. Given this situation, and the fact that my favorite seat is front and center, how do you set up the projector? It seems if you adjust the brightness and contrast for the front and center seat, it will be too bright for the back row and too dim for the front side seats and vice versa if you set it up for the other seats. If it was just a minor difference it would not be that bad, but we are talking about major differences in brightness here.


If I just had the one row of seats in the back I think it would be a no-brainer and I would get the High-Power. However, with my current set up, I think it would make me crazy for everyone in the theater to be seeing different images. The Video Spectra was pretty consistent from all seating locations, however, there was a "sparkliness" to the material that I am not sure I liked, and I have heard some bad stories about waves in the fabric on a pull down. The matte white was very consistent, however, it looked just like my Parkland and I would not consider it an upgrade.


Any suggestions?"
 

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You deal with varying brightness because this screen material is NOT made for viewing off axis. You probably know by researching this material that it,s benefit comes from sitting close to the projector,s light path ONLY. It Truly boggles my mind that people are using this material with cieling mounted PJ,s, they would be better off with 1.3 gain WIDE dispersion material. I hope people aren,t reasoning that because there off axis that the gain comes back closer to unity gain so why not use it anyway, wrong it,s not MADE for that purpose, read the manufactuers rating ,they know best
 

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Discussion Starter · #3 ·
I think I understand why it is doing it. It is just that there have been so many people that have posted that they ARE using this material with a ceiling mounted projector and are raving about it, that I am trying to figure out how they are getting such good results.


Like I said, from my back row, which is raised up and only about 2 feet below the lens of the projector, the image is great and consistent across all three seats. It is my front row that has all the problems.


That is why I am wondering if those that are using this material in a ceiling mounted application just have one row of seats (all within the viewing cone), or am I just being too critical of the varying degrees of brightness?
 

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Gator123. The brightness and contrast settings should not change with varying screen gain, just as the contrast ratio doesn't change between screens of different gain. Only the absolute black and white levels will be shifted, so that like you said, the front row will have a less bright image than the back row, but all in all the projected image would still be "setup" properly.


I'm using an HS10 with a 106" High-Power, and since I'm using the long throw conversion lens with my projector, I'm able to place it more than 20' back from the screen. When seated in my first row at about 12', the image is awesome. Of course the second row, which is 12" higher, is even brighter, but because of my extreme throw distance, the angle between the projector's light rays and my sight lines are less than 10 degrees even in the front row. This retains much of the gain of the High-Power screen.


Just my .02
 

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I am thinking about switching to the High Power because so many people have reported that it makes waves in the fabric unnoticeable. I have a big problem with waves on my Video Spectra right now. Very annoying.
 

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Discussion Starter · #6 ·
DMILANI, Thanks for the input. I can see how you would not change the contrast setting, but I guess I just do not understand why brightness settings would not change between screens of different gains. It seems like if you set brightness to the "correct" level with AVIA or VE on a Matte White screen and then switch to a High Power screen, the image would be way too bright. If you or someone else could explain this further I would really appreciate it.


Also, do you notice a difference in picture quality and brightness across your front row seats? Since my projector is about 17 feet back from the screen and about 6.5 feet off the floor I would think my viewing angles are not that bad. However, while the image from my back row is much brighter than the front row, at least it appears to be consistent across the entire back row. It is the front row where it really drops off for the two side seats.


At this point I like the image from the back row so much, I am really tempted to just go ahead and order a High Power screen in a slightly larger size (52" x 92" vs the 47" x 84" I am currently using), move my prime viewing seat from front and center to rear and center, and say to heck with the front row side seats. In actual practice I rarely have enough people over to fill those seats, and the picture will only look dim in comparison to the other seats. In reality the image from those seats will probably be about the same as my current setup (with the Parkland Plastics DIY screen) anyway.


Whatcha think about this plan?
 

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Gator123:


I think the point of confusion for you may be our "reckless" use of the word "brightness". What you are experiencing when you say that you have brightness variations across your seats is relative brightness of the picture as compared with the darkness of your room.


What "brightness" means though in terms of image calibration is "black level" as opposed to "contrast" or "white level". This, I believe, is referring to the highest output your projector is capable of (white level) and the lowest output your projector is capable of (black level). This difference makes up contrast ratio, and this typically does not change with pure changes in gain, so long as the color of the screen material doesn't change (white/gray).


So, yes, you will see relative brightness variations as you move within or without the viewing cone of the high power screen, but the absolute contrast ratio of the image should not change. This doesn't mean that people don't or shouldn't recalibrate their projectors in concert with whatever screen they are using. It *does* take two to tango, as they say.
 

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jwtseng is correct regarding the "brightness" adjustment. The term brightness, which I guess was coined half a century ago when the first TV started to appear, is just a very bad choice of word. A better term would be "black level," which is used in some projectors such as the Epson TW100/Yamaha LPX-500.


What the adjustment really does is to change the "offset" of the projector's gamma curve in the low IRE regions. If set too low, you start to lose shadow details; set too high, the black starts to be washed out. Correctly set, your projector produces its best blacks, with its best shadow details.


Most importantly, the optimal brightness/black-level setting does not change at all with varying screen gain. So you do not have to worry about it in your case; in other words, you cannot do anything about it by changing the projector settings. Once you calibrate your projector in any one of your viewing positions, that is it for all others.
 

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Discussion Starter · #9 ·
jwtseng and Sushi - Thanks for the replies, I think I understand "brightness' a little better now.


Just for an update, I was playing around with the screen samples again last night and there were a few more things I noticed about the High Power. While the "brightness"/gain outside of the main viewing cone (front side seats) was no better than the Parkland Platics screen it was taped to, the whites still appeared whiter and the image looked a little smoother from these angles. When I placed the sample in the middle of a large white surface, the sample looked white, while the rest of the image looked kind of "dirty", so while the brightness is no better from these extreme angles, I think the overall image will be slightly improved.


I experimented by moving the sample around to a bunch of different areas of the screen and different scenes from Shrek, 5th Element and MIB II. From the back row with any bright colors (Shreks head, Lelu's hair) or whites, the difference was amazing. The High Power really made them pop.


For skin tones, I think there was an improvement although my wife felt the High Power made them look more red and she preferred the PP.


In dark scenes there was more shadow detail with the High Power, however, the not so great blacks of my older LCD projector really started to look gray, or should I say "grayer". I think I remember from reading here that that is all relative as when you have an entire screen rather than a small sample, the whites will be so much whiter that the blacks will still look the same. The only real problem with blacks was when I put the sample up against the black velvet border of my current screen. Here the black really looked very light gray in comparison to the Parkland.


Finally, while I thought that overall the High Power was a significant improvement in a bunch of areas, with the only negative being black level as compared to my screen border, my wife said she "just did not see it" as being that much better. When I pointed out the brighter more vibrant and intense colors, she said she thought it "just looked a little brighter" and that the colors did not look that different. I could not understand how she could not see the improvement until she said that she liked the "look" of the fixed DIY screen I made and was not sure if she would like the way a pull down screen would look in the room. I have a feeling that the looks of the actual screen itself might be influencing her "unbiased" opinion of the screens performance. In the end, she said that I should just go ahead and order it if I wanted, but she did not think it would be that big an improvement.


Now I am back on the fence, but I guess it is my own fault for asking her opinion in the first place! :)
 

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Gator123:


Don't ever discount WAF!!! :D


I think that the smoothness of the image on the high power screen is exactly what I am looking for. And if the image is brighter, then that's all the better for me. Thanks for giving us your impressions so far. I am eagerly awaiting my sample swatch and I'll probably be ordering my screen shortly thereafter.
 

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Quote:
I think I remember from reading here that that is all relative as when you have an entire screen rather than a small sample, the whites will be so much whiter that the blacks will still look the same.
Exactly. Your eyes and brain will quickly adjust itself to the average brightness of the entire screen, so in the end, the black will "look" the same as compared with a lower-gain screen.

Quote:
I could not understand how she could not see the improvement until she said that she liked the "look" of the fixed DIY screen I made and was not sure if she would like the way a pull down screen would look in the room.
Well, why don't you then just buy the High Power fabric alone, and swap the existing PP fabric on your DIY frame with it?
 

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it may actually be cheaper to buy a model B screen and cannibalize the high power fabric than to buy the material alone. someone previously posted these prices for the material:


high power fabric alone - $13.25 per sqft

high power fabric with velcro and black border - $15.59 per sqft
 

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Discussion Starter · #13 ·
Sushi- Great idea!


Actually I also remember reading somewhere that if you just want the fabric, the most cost effective way to go is to buy the Model B and pull the fabric out of it. This way, I can get a Model B, mount it just above my existing screen, and if she does not like the look, then I can either roll it up when I am not using it and have two screens, or just pull the fabric out and mount it inside my existing frame. The front wall of my theater is painted flat black, so if I order a Model B with the black case, the case should pretty much dissapear when not in use.
 

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Discussion Starter · #14 ·
Oops, Bobanala posted that exact thought while I was typing.


Just goes to show the great information available so quickly on this forum (and how poor my typing skills are)!
 

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well. I heard so much positive, and so little negative (none) about the high power, I ordered one. Currently it's sitting in my car awaiting a ride home to be installed. I'll try to post my reactions later once it's up and running.


Currently I'm shooting onto a piece of bright white paper, stapled to the wall. So anything may well be a vast improvement. :)


-Jason W
 

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JW,


So tell us how it went last night!
 

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Well, either Studio Experience screwed up, or Dalite did. Either way i got a screen with the proper size and added drop, but, CSR which I didn't order, and the material was High Contrast Matte White, instead of High Power. Grrrrr.


I do REALLY like the CSR feature now that I've seen it. I thought it was just a safety feature to keep the screen from slamming into the case, but it actually makes the whole trip up a controlled speed return. Really feels classy, and really makes the screen seem to be of much higher quality.


So now, I've got to get the proper material in, and get it up. The good news is, I can do a 'Pepsi Challenge' and see which one I like better now.


BTW: the mounting, super easy. Just hold the thing up touching the cieling, against the wall. had my wife mark the holes with a marker, ran some drywall mounts into the wall and it locked in place, easy pleasy. Took less than 10 minutes. With the added drop in the material, it has the versatility of being any height you want, and raising up to be far out of the way. I plan to run crown moulding over/around it, to hide it up against the cieling. Should work out well.


I'll keep everyone posted.


-Jason W
 

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jw, in addition to what you have said, I understand that CSR actually protects the fabric from waving by preventing the uneven speed of retraction.

Quote:
BTW: the mounting, super easy. Just hold the thing up touching the cieling, against the wall. had my wife mark the holes with a marker, ran some drywall mounts into the wall and it locked in place, easy pleasy...
Is yours the Model B or Model C? Also, was the "drywall mounts" provided by Da-Lite, or the generic one available at Home Depot? I ask this because I understand that the Model C, which I ordered, is pretty hefty (over 60 lb), plus the mount will also have to tolerate the repetitive pulldown force on top of the weight of the screen.
 

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sushi........

What projector are you running?

I'm hedging between a 106" diag. High-Power Contour Electrol (~$1000) or a 100" diag. Firehawk Luxus A ($2500).

Big price difference. I have a Sharp 9000 DLP (800 lumens).

My concern is the angle of PJ vs. screen vs. seats.

I can get the "telescoping" Sharp ceiling mount to cut-down the angles.

Any thoughts from others?

Terry M.
 

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tmpsu,


My projector is the Yamaha LPX-500, which is probably slightly brighter than the Sharp Z9000 in the measured actual lumens. I ordered the 8'x10' High Power, aggressively custom-masked down to 120" diagonal. I needed a large fabric to hide everything on the front wall behind when the screen is down.


I thought that the High Power would be best with respect to the brighter "punch" in image and ambient light tolerance. I will mount the projector on a stand at just below eye level, in order to maximize the benefits of the High Power fabric.
 
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