Screen choice for Epson Powerlit Home Cinema 720 - AVS Forum
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post #1 of 3 Old 03-11-2008, 02:00 PM - Thread Starter
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Hi all,

I got the Epson Powerlite 720 a week ago. I'm very new to projectors and such and have spend almost a full day looking this stuff up, but would still like some help from your experiences/knowledge.

The projector is now firing at a white (very smooth) drywalled wall which is indented in and surrounded by some moulding to make it look pretty (my father-in-law's idea...). When I set the projector to Theater Black 2 (I assume this to be the best setting without blowing things out of wack), I see that in the projectcentral review, it states the projector then works at 331 ANSI lumens (1600 lumens for this thing is only in killer Dynamic mode).

So, here are my dimensions and thoughts, and some of the questions I have are listed below all this.

Room: 19'3" L x 12' W (so fairly narrow and long)
Screen indent: 91"W x 61" H (about 2'6" off ground before it starts)
Projector distance: 15'3" away and about 7'6" above ground.

I would like to fill up that screen-indent area with the most I can, so I'm guessing that would be a 106" (52" x 92") without being much too tight. That translates to a screen with 33.22 square feet. Also, to get that sized screen from the distance I have the projector would mean the projector is operating at 1.56x zoom, which I'm assuming translates to a loss of 22% ANSI-lumens, as " At the maximum telephoto setting, the projector loses approximately 45% of its total light output." (from projectorcentral). So that brings the ANSI lumens down to 258 (I assumed the drop in light output is linear, and though that may not be the case exactly, I don't think it will through the numbers off too much).

So, with the formula I see everywhere:
ANSI-lumens of your projector / Square footage of Screen * Screen-Gain
= Image brightness in foot-Lamberts

To get an screen between 12-22 Ft-L, I'd need a screen-gain between 1.55 and 2.83 - maybe the Da-Lite High Power 2.8 gain surface. This is in a completely dark room. The projected image now looks dim and definitely lacks punch.

Questions:
1. What is the typical gain of a smooth white wall?
2. Is the lack of punch the fact that it's dim, or not against a screen of some kind, or just the projector; though I doubt the latter based on the reviews I've read for it.
3. How come many people seem to be projecting their Epson with Theater Black 2 (or similar projector) with a similar size, yet don't seem to mind that they don't have a screen with a decently high gain? Are my numbers wrong (and the wall is very low in gain)?
4. Recommend making my own screen from some of the DIY guids out there? Can I get such a high gain with it?
5. Do you recommend I seek for 2.8, or do you have suggestions go to to something like 2.2 (and where can I get something like that)?

Thank you so much!
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post #2 of 3 Old 03-11-2008, 04:04 PM
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1. This is just a guess, but 1.0 or maybe a touch higher depending on the reflectivity of the surface?
2. Our setup is very similar. I'm projecting to a 106" diagonal 16:9 screen, which is 92X52 from a throw distance of 16'. I run the projector in Theater mode nearly all of the time. The colors actually look more accurate in that mode anyway....at least on my projector. The only downside is bulb usage and fan noise. But I'm getting a free bulb with the rebate, so that's not as big of a concern. And the fan noise just doesn't bother me all that much. If those things don't bother you, then give Theater mode a try and see how you get along.
3. I started with blackout cloth, which is around 1.1 gain. I'm now using Elite Cinegray, which is a gray surface with 1.0 gain. I don't care for that surface.....makes the image too dingy and dim. I actually just ordered both Elite Powergain AND Cinewhite screen materal to try out. I'm guessing I will end up using the Powergain, but if I don't like it, I'm sure I will like the Cinewhite material as I'm guessing it will be very similar to the blackout cloth I was using.
4. Others will have to chime in on that one as my only DIY experience is with thumbtacking BOC to the wall.
5. This depends on how bright of an image you want. If you like it bright, then a High Power might work, but you'll have to set it up properly to get full benefit. Check out the High Power Calculator thread. Personally, I wonder if that might be TOO bright for my tastes. That's why I'm giving the Elite Powergain material a try....it's 1.8 gain.

Have an Onkyo 805 receiver and having trouble setting up Audyssey? HERE is a mini how-to.Click HERE to check out my comparison review of 5 different projection screen fabrics.
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post #3 of 3 Old 03-11-2008, 06:40 PM - Thread Starter
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Quote:
Originally Posted by Chad T View Post

5. This depends on how bright of an image you want. If you like it bright, then a High Power might work, but you'll have to set it up properly to get full benefit. Check out the High Power Calculator thread. Personally, I wonder if that might be TOO bright for my tastes. That's why I'm giving the Elite Powergain material a try....it's 1.8 gain.

Thanks - I'll have to check out the Elite Powergain and I'll check out that High Power Calculator. I'm also concerned about 2.8 (being on the high end of my calculation), so that might make it quite bright. I'd like a 2.2/2.3 like I mentioned earlier.
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