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Discussion Starter #1
OK folks. For starters, I currently use a G1000 with a 10 foot wide Stewart screen. In the spring I will be radically remodeling my home theater area. The room which currently houses the theater will become a full-featured lobby with concessions, etc. And an adjoining room which currently houses a swimming pool will be converted into the theater. This new room will allow me to go with a larger screen. I have recently added a panamorph lens so I will be able to use the entire panel of the DILA. (don't hate me I bought the lens from someone here on the forum) I know that Dean here on the forum uses a G15 with I believe a 15' wide screen. I am actually thinking 18 to 20 foot wide 16:9. Do I go with a G15 or G20? I can get a B stock G15 for 8500 and a B stock G20 for 10500. Decisions decisions. Of course I have DILARD and will use it and I hope to switch to a microperf Greyhawk. Am I crazy. Will the results suck or am I on the right track?
 

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You might want to do some searching, to find the details - this has been discussed recently. Basically, the G15 tends to produce better contrast, post calibration, than the G20. It can even be brighter. So, I'd say to go with the G15. (And I have a G20!)


I don't know about that screen size - it seems kind of big, but with the proper light levels, and at a 1.5x screen width and more, I would think it could work, if anything would.


- Dave
 

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Discussion Starter #3
Thanks Dave. I actually have been searching the forum I was just hoping to hear from some actual G20 owners out there. I wil probably go with the G15. By the time the room is actually done there may even be better alternatives available.


Anyone else out there care to give me their takes on the idea?
 

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20 ft. wide 16:9 you must have a very high ceilings?
 

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Quote:
Originally posted by thaxx
20 ft. wide 16:9 you must have a very high ceilings?
20' wide = 135 inches tall. WOW!:eek:
 

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Hi Chris,

glad to hear the panamorph is in good hands.

If you go ahead with the plan as stated, I think you will be disappointed with the image.

At 18ft wide your screen brightness will measure less than 6 Ft-Lamberts, if you use 1100 ansi lumens as the post calibration output of the G15.


If you use conventional thinking, with good control of ambient light, I would think that a 12 foot wide 16:9 screen would be about the limit to get acceptable screen brightness. This would produce between 12 and 13 Ft-Lamberts.


All assumptions above with a Greyhawk microperfed. You could consider a 2.0 gain screen with perf and then things get a little more interesting.
 

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I have to agree with Don - a G15 and that size screen is a poor match.


If you go with a 20' wide 16:9 screen - you've got 225 square feet of screen area.


Given that the 1500 lumen G15 will end up at about 1000 to 1200 lumens post calibration and the gain

of a GrayHawk is 0.95 - then you are only going to have about 5 or 6 foot-lamberts on screen.


In other words - with that size screen - you are going to have a very dim picture.


You need to get AT LEAST another factor of 2, and preferably 4 in screen brightness. Perhaps dispensing

with the GrayHawk and get a high gain screen with a gain of 2.0 AND halve the area, and you will have

something that is more watchable.


Greg
 

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For what it's worth "The Perfect Vision " in its latest article recommends 8 ft - 11 ft. wide (not diagonal) as the perfect size screen for a D-ILA.
 

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Rick,


"Perfect Vision" is assuming a 1500 lumen G15 and targeting for 20 - 40 foot lamberts.


They are not factoring in the reduction in G15 light output after calibration. [ JVC calibrates

G15s for maximum light output as their target customer use is business presentations. If one

calibrates for HT use - you lose 20-25% in brightness. ]


TSHA222,


The other thing you have to remember is that the G15 has a throw ratio of 2.1 to 3.1, zoomable.

So if you want a 20 foot wide screen, the G15 has

to be at least 42 feet away from the screen.


Greg
 

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I help folks with custom installations. I use and demonstrate a G-20 on an 11ft wide screen, 16:9 format. I would not recommend a screen wider than 12ft and if you are going to be using a screen wider than ten, I recommend the G-20 over the G-15. This is particularly true if you will also be using your theater for observing sport events where you are more likely to desire some ambient light. (Frequently a group/social event that does not take place in total darkness.)


If you are going to a ‘mega’ home screen, and it you can afford it, you should consider a 3-chip projector.
 

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Sore Eyes:


I'm not so sure about that - that is, if the projector will be properly calibrated. Cliff, who's calibrated quite a few of these, says that the G15 will be brighter, after calibration, than the G20. Check out this thread, to see his quote.


I wish it weren't true - I own the G20, and I picked it over the G15 for exactly the reason you gave (better for ambient light viewing). But, Cliff should know.


- Dave
 

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The G-20 that I currently show was calibrated by JVC. Drop by and you will see. (Carmel, Ca.)


Yes contrast ratio is critical. But larger screens demand more pure power to provide enough punch in order to create an involving experience. I am not persuaded that the average G-15 will produce more light than the average G-20 after both have been calibrated.
 

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Chris,


I'm using a Cliff calibrated G20 with a Panamorph on a 9' wide 16:9 microperfed Grayhawk. I have 390 hours on my lamp and have not noticed a drop off in light output. I'm not saying it hasn't dropped off; I'm just saying I haven't noticed it.


I have more than enough brightness and could easily drive a larger screen...if only my installation allowed me to do so.


Given that people that have spent time with both G15's and G20's don't see a big difference you may want to go with the more economical G15. The G15 costs less to buy and replacement bulbs are several hundred dollars less too.


On the other hand, you're talking about a very large screen; the G20 may have some advantage in your case.
 

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JVC doesn't drop the light output anywhere near as much as Cliff (or William Phelps). JVC doesn't care as much about getting the color to 6500K. I had mine calibrated by JVC when I got it, but ended up having it done again by Cliff.


Again, I have a G20, so I'm not trying to justify my decision. My G20 is awesome, and waaay bright. But, I'd get the G15 if I did it again - saving money, and getting a marginally better picture.


To each his own.


- Dave
 

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Discussion Starter #16
Thanks for all the comments guys. It has been a little bit since I checked in. I am strongly leaning toward the G15. As far as the room ceiling height goes, the room currently houses a swimming pool. The pool takes up the entire width of the room (20) and the ceiling height from the bottom of the pool (it is lap pool with no seperate shallow end deep end) to the ceiling is 16 foot. My idea was to create a stadium style setup. I don't know where I got the idea I could go 20 foot wide. But I do think I could go 15 in that room. If I go with a higher gain screen I should be cool from a brigtness standpoint but image wise, I may be better off with the Greyhawk. Perfed would be preferred but I understand that would probably decrease my brightness. As far as going with a 3Chip DLP, man if I could afford a system like the one used at the Pleasure Island AMC 24 where my wife and I saw Monster's Inc I would jump on it. But unfortunately that is out of my price range. The good news is I have some time to finalize things as I am not getting hot and heavy with a remodel until spring. So I'm going to go with the G15, calibrate it, paint the screen wall and see just how far I can push it and still be happy with the image quality. I will keep you all informed. Thanks again for ALL the input.
 

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Chris,


Will you still be able to float on the swimming pool while watching a movie? Or are you taking the pool out?


I always thought that it would be great to have a hot-tub in the theater room! Kicking back with a glass of Merlot in the Hot Tub while watching Gladiator in 10.2 surround sound. Hook some transducers up to the walls of the hot tub for that "over the top" touch.


Ahh....it sure is fun to dream.
 

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Unless you can totally black out the area, with everyone seated first and no need to get up during projection, anything as large as 15' will require lots of light power. I have G-15 on just under 10' Greyhawk, and it's barely bright enough at night (very dim downlights).


I second other comments - get bright screen, use G-20, and bias the calibration toward power, and sacrifice some black level shadow detail; or colors will not be vibrant, and contrast cannot be maintained, at that size.
 

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Discussion Starter #20
Stew,


The room will be totally dark except for some step illumintation lights. I currently have a G1000 with a 10' wide 16:9 screen and find the image extremely bright even after calibration. I have seen folks use CRT projectors to 10' and bigger. They were happy with the brightness while I was not. I will ulitimately go as big as I can while still happy with the results.


Milori,


The pool will be drained and the whole room will be redesigned to take advantage of the high ceilings. I'm going for a stadium seating configuration. (at least that's the hope)


PS Thanks for DILARD - a great piece of software!


Mohy,


B Stock in this case means demo. There is a company that I buy product from and they are great at customer service and stand behind their demo deals. The two DILA's they have now both have under 24 hours on them. Not brand new, but I have been more than happy with a Proxima DILA (G1000) that I bought used early last year. A new bulb and it was like new, calibrated and it was better than new!
 
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