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Discussion Starter · #1 ·
Preface:


I realize I should just put the PJ at the current throw distance and see how much of the tube face I need to fill the screen. I justed wanted to "throw" this out there to gain any benefit from the experience of others.


My computations for my 294cm wide screen come up with a throw distance (TD) of 408cm for my BG808. Based on the location of my current ceiling mount, the closest I can come to this is 392cm for a difference of 16cm or just over 6 inches.


Those calculations are from the BG808 install manual's formula. Running the LENS program for a BG808S, I get the somewhat closer value of 397.3 cm which is only off by a few inches from my current mount.


I think that's pushing it. What do you guys think?


The screen is a 133" diagonal 16:9 with a width of 115.9" for reference in English measurements.


Why do I ask? I have 2.5" to move backward before I have to tear a new hole in the ceiling and move my mount back to the next set of joists.


Thanks in advance.


- Jerry
 

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I have an animal of a different species...an NEC XG-852.


"By the book" throw distance for my 90" wide screen is about 130" yet, I'm able to fill my screen (by enlarging the rasters) and using powerstrip, to fill the screen at a throw distance of only 112". That is 14% less than the manual specifies.


It looks like in your worst case scenario, you are off by just under 4%. without having to move your mount.


As you can see, I'm a big fan of maximizing the use of the tube face, making sure of course, that the image area does not run up to (or beyond!) the edge of the tube face. In my setup, the raster outline itself stays just within the tube face while the active image area has still a good distance to the tube edge on either side.


I realize this a bit aggressive, but from what I've read the concensus is that it is still safe. I don't think I would be able to do this, of coure, if I had a 4:3 setup either.


Again, this is an NEC so your mileage may vary.
 

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Discussion Starter · #3 ·
Thanks for the feedback. I think the theory applies regardless of the projector. Since I'm also using a 16:9 screen, I can steer away from the top and bottom of the CRT face and maximize the use of raster where the tube is most square.


I'm going to line her up tonight and see how the she fairs. The alternatives are far too much work!
 

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Jerry, I'm sure you've already found this out, but the LENS program does seem to put the projector back farther than it needs to be, especially for a 16:9 screen configuration.


Most of the manufacterers built some error into their throw distance estimates to prevent tube failure from getting the image too close to the edges. Not all installers are the masters that frequent this forum and that run their systems a tad closer to the screen then spec.


If your off by just the amount you are talking about above, I think you'll be fine getting it all to work out. :)
 
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