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I will have 12 ft ceilings in my new HT. What are the special considerations for ceiling mounting a projector at an angle? Is this what is meant by keystone correction? Does this type of adjustment work well or do I need to drop my projector? I haven't picked one yet so I can choose whatever will work, I have 10k for proj/scaler/etc... Thanks.
 

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Unless you get a projector with a lens offset (Seleco HT250 and Epson 8100 come to mind, but they may be too expensive), you will need to drop the projector. Even with offset, you will probably have to drop it some. Digital keystome is fine for small corrections, but can become objectionable if you're off by more than 2 or 3 feet.



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Steve
 

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Most digital projectors provide "Digital Keystone Correction". You do not want to have to resort to that. That would mean the projector has to digitally distort the image to compensate for the optical distortion. This will rob you of some digtal resolution. The only decent keystone correction is purely optical.


Your best bet is to extend the projector mount down to 9 or 10 feet.


Go to www.chiefmfg.com (mounts)


You need to determine your projector's throw ratio/distance and your desired screen size. You can then decide how far back and down your projector needs to be...
 

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Or you could just get a REALLY big screen... say 16'*9' and then you wouldn't have to worry about lowering the projector or any keystoning problems! http://www.avsforum.com/ubb/biggrin.gif A 2,000 lumen projector would be enough to light that baby up if you had an anamorphic lens. Oh damn, I just saw your budget... maybe a moderately higher gain screen would work with a 1300 lumen DLP or LCD...


Man, I wish I had such high ceilings. There's so much you could do, you could have multiple rows of tiered seating and you wouldn't have to worry about running into the ceiling, you don't have to worry about where the place your centre speaker so it won't interfere with the screen, oh I'm so jealous.


How big is your room? It doesn't even matter if it's not very large, at CES I saw the JVC theatre and it wasn't very deep. The inter-pixel gap on the D-ILA is good enough that from 6-7' from the 12' wide screen you couldn't see the screen door effect. Once you see such a nice image on such a large screen, you don't want to go back!


Regards,


Kam Fung
 

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The Selecos have 27 degrees of keystone correction (10 degrees mechanical,

17 degrees digital). You can suspend the projector on a ceiling mount with a variety of pipe lengths, but 27 degrees is a lot of potential correction so you may be O.K. right on the ceiling. If,as you say, you've got 21' to work with, you should have no problems. The Seleco's also have a long throw distance.
 

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"Man, I wish I had such high ceilings. There's so much you could do, you could have multiple rows of tiered seating and you wouldn't have to worry about running into the ceiling, you don't have to worry about where the place your centre speaker so it won't interfere with the screen, oh I'm so jealous."



It's not as great as you might think. I have two rooms for HT that work on my house. One has 21 foot ceilings and one has 9 foot ceilings and it's a real problem if you don't want to drop the projector on a pole for esthetic reasons, or because you'd rather put a heavy CRT projector up there, which I'd certainly rather not want to hang from a pole. I believe that the ideal spot for the screen is about 2 feet up from the floor so that a seated viewer's eyes are about mid way up the widescreen. If you don't drop the projector, you end up placing the screen too high.




[This message has been edited by PF (edited 04-29-2001).]
 

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As one poster said above, you don't ever want to use digital keystone correction, it rarely does a good job. If you get the Seleco the 10 degrees of optical keystone adjustment should be more than enough. Also if you are going for a big screen with a moderately long throw distance (as opposed to a short throw, like a CRT), you will be able to mount your projector on the rear wall. That should take care of any problems with mounting height, as you won't need to hang it off the ceiling.


In your case with such a high ceiling I would definitely urge you to raise you back rows of seats, you could have as much as a foot difference in height between each rows with not problems. The higher seating in the back rows will also allow you to raise you screen a little higher without having people strain their necks too much.


Regards,


Kam Fung
 
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