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I am going to be setting up a BG800 for a friend. According to Guy Kuo and others the PJ should sit level and not be tilted. The screen is going to be a couple of feet lower than the PJ. If you are not supposed to tilt the PJ down (in relation to the screen) how do you project the image downwards onto the screen. I have set up a couple of the BG800s before but the screen has always been very close to the same height as the PJ. I am quite familiar with all other aspects of setting this unit up so I only need an answer to this question.

The only solutotion I can think of is to tilt the bottom of the screen upward to negate the downward tilt of the PJ. Is this the only way? I have seen many pics of installations where the screen is lower so I know it can be done.

Thanks

Steve
 

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Keep in mind that when you mount the projector level the lenses will tilt downwards-when your projector is 127'' away from the screen this will be enough to drop the image down a good foot or so-and you will have adjustments to correct keystoning and any other distortions.

Wayne
 

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I think he means that with the BARCO the top of the screen is the same distance down from the ceiling as the bottom of the projector. The lenses naturaly project an offset angle around 12 degrese.


I woud tilt the project just enough to make the image work so that the rasters are still centered. I think you will have enough in the keystone adjustments to square the image up to the screen without pushit too hard on the electronics. This is why projectors have keystone so you can suite the installations.
 

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Steve,


run the Lens program, with the screen width and aspect ratio you plan on using. If it's a 16x9 screen, you'll get some drop for "free". Check the A value, it should be negative. That's how far down from the base of the PJ the top of the screen will be (assuming you're doing a ceiling mount here).


If it's not enough, you can change the mounting angle from 10.5 to 11.0 (and so forth) right on the layout form, and see how quickly the A value increases. You'll probably get an error message before you get very far, saying that you can't exceed some small angle at the default horz scan rate for the PJ (using a BG801 from the Discontinued menu). Go back to the Input form, and drop the 94 kHz rate down to 60 kHz. Then return to the Layout form and continue increasing the angle until you hit the drop point you need.


Checking to see how far off from 10.5 you are at that point will tell you if what you're attempting is feasible or not, without major sacrifices in PQ.


If the screen is going to be closer to the floor than the ceiling, you may be better off doing a floor mount. If it has to be on the ceiling, you might need to drop the PJ a few inches. Let us know, if you'd like some feedback on the results.


Vic, the angle on the Barcos is 10.5 degrees.


- Tim
 

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Energeezer wrote:

> The only solutotion I can think of is to tilt the bottom of the screen upward to negate the downward tilt of the PJ. Is this the only way? I have seen many pics of installations where the screen is lower so I know it can be done.
 
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