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Need assistance with projector placement in my new media room

post #1 of 18
3/3/13 at 9:45pm
Thread Starter 
I have a new house that has a Media Room. The room measures 20' by 15' 8". The room is prewired for power and cable smurf tube at a distance of 15.5 feet from the wall where the screen will go. My equipment cabinet with center channel is going to be 29" tall.
I am planning on a 110" diagonal 16x9 screen, from looking at calculators on the internet I am figuring the screen will be around 60 x 102 with a 3 inch black felt border included. I am purchasing a JVC DLA-RS50U projector. My question is how far from the ceiling should the center of the lens be on the projector? From reading up on this it seems the opinion is it should be level with the top of the screen. SO, I am figuring that the equipment on the floor takes up 30", then 60" of screen and another 30" of wall to the ceiling. Am I correct in calculating that the center of the lens should be level with the top of the screen? Meaning it needs to be 30" down from the ceiling?
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post #2 of 18
3/3/13 at 10:53pm
Quote:
Originally Posted by RickFinn View Post

I have a new house that has a Media Room. The room measures 20' by 15' 8". The room is prewired for power and cable smurf tube at a distance of 15.5 feet from the wall where the screen will go. My equipment cabinet with center channel is going to be 29" tall.
I am planning on a 110" diagonal 16x9 screen, from looking at calculators on the internet I am figuring the screen will be around 60 x 102 with a 3 inch black felt border included. I am purchasing a JVC DLA-RS50U projector. My question is how far from the ceiling should the center of the lens be on the projector? From reading up on this it seems the opinion is it should be level with the top of the screen. SO, I am figuring that the equipment on the floor takes up 30", then 60" of screen and another 30" of wall to the ceiling. Am I correct in calculating that the center of the lens should be level with the top of the screen? Meaning it needs to be 30" down from the ceiling?

You don't need to drop it down level with top of screen....the projector has vertical lens shift so it is not necessary. The vertical range is 45% of the image's height.
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post #3 of 18
3/4/13 at 7:19am
Thread Starter 
OK, thanks, so is there a standard or preffered distance? 1 foot? i was thinking for maint or if i add a 3D emitter later.

also, any suggestions on brand and type of mount? i understand they dont sell the down pipe with them, where do you get that and what type? Threaded?
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post #4 of 18
3/4/13 at 8:20am
Quote:
Originally Posted by RickFinn View Post

OK, thanks, so is there a standard or preffered distance? 1 foot? i was thinking for maint or if i add a 3D emitter later.

also, any suggestions on brand and type of mount? i understand they dont sell the down pipe with them, where do you get that and what type? Threaded?

One foot is plenty....I like the chief RPA-281...you need the basic ceiling mount, ceiling plate and quick connect extension.
http://www.chiefmfg.com/Products/RPA281
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post #5 of 18
3/4/13 at 2:17pm
Thread Starter 
Thanks for the advice, i ordered the Cheif mount. I also went with only a 3" pipe to connect it.
With a 10 foot ceiling, thats still ok, right? Sorry to keep asking, just cant wait until Saturday to climb up the stairs with food and drink in hand and tell my wife i wont be coming down until its Movie Time.
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post #6 of 18
3/4/13 at 10:28pm
Quote:
Originally Posted by RickFinn View Post

Thanks for the advice, i ordered the Cheif mount. I also went with only a 3" pipe to connect it.
With a 10 foot ceiling, thats still ok, right? Sorry to keep asking, just cant wait until Saturday to climb up the stairs with food and drink in hand and tell my wife i wont be coming down until its Movie Time.

That will bring the center of the lens down around 8" from the ceiling...so then you have another 22" to the top of your screen. It should work but you will be using most of your vertical lens shift. I would probably not want to use that much vertical lens shift. If you can change the pipe to 6" it would be better. Using that much vertical lens shift can reduce the light output of the projector. You can also buy 1.5" plumbing nipple in various lengths at Home Depot for practically nothing and spray paint it black if you want to try a different length.
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post #7 of 18
3/5/13 at 6:06am
So wait, and I assuming correctly that it (the PJ) can/will be mounted on the wall and shone across to the other side?

Then you could always do something like this with a shelf:

James
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post #8 of 18
3/5/13 at 6:12am
BTW: how are we calculating how far the PJ needs to come down without knowing the ceiling height or where he wants the bottom of the screen (I'm assuming the bottom of the screen will be ~30" off the floor to sit above his rack/center channel)?

OOPS. just noticed the 10' ceiling down a bit, sorry. So: if the bottom of the screen is 30" off the floor, and it's 60" high, that leaves ~30" to the ceiling from the top of the screen?

So further assuming the PJ throws the center of the image straight ahead, with the PJ 8" from the ceiling that means the screen center needs to drop ~ 52" to be in the middle of the screen if the bottoms at 30", correct?

Basically: the 8" mount distance cuts the 30" between the top the screen and ceiling down to 22" (as noted) but then you need another 30' to get to the middle of the screen, so 22" + 30" = 52"

How is this going to happen with ~24" of vertical LS and the PJ just 8" from the ceiling?

Seems to me the PJ will have to be lowered at least 3 feet from the ceiling to meet the center of a screen that's 5 feet from the ceiling.

James
Edited by mastermaybe - 3/5/13 at 7:55am
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post #9 of 18
3/5/13 at 8:20am
Quote:
Originally Posted by mastermaybe View Post

BTW: how are we calculating how far the PJ needs to come down without knowing the ceiling height or where he wants the bottom of the screen (I'm assuming the bottom of the screen will be ~30" off the floor to sit above his rack/center channel)?

OOPS. just noticed the 10' ceiling down a bit, sorry. So: if the bottom of the screen is 30" off the floor, and it's 60" high, that leaves ~30" to the ceiling from the top of the screen?

So further assuming the PJ throws the center of the image straight ahead, with the PJ 8" from the ceiling that means the screen center needs to drop ~ 52" to be in the middle of the screen if the bottoms at 30", correct?

Basically: the 8" mount distance cuts the 30" between the top the screen and ceiling down to 22" (as noted) but then you need another 30' to get to the middle of the screen, so 22" + 30" = 52"

How is this going to happen with ~24" of vertical LS and the PJ just 8" from the ceiling?

Seems to me the PJ will have to be lowered at least 3 feet from the ceiling to meet the center of a screen that's 5 feet from the ceiling.

James

1. The JVC specification for the RS50 has an 80% lens shift
2. For a 54" high screen, 80% shift means 16.2" above/below screen
3. 30" from ceiling to top of screen
4. Foot print of mount with projector 5.5"
5. leaves 24.5" distance from projector to top of screen.
6. means extension pipe need to be at least 8.3"
7. I recommend going with 1 foot extension to prevent maxing out vertical lens shift.
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post #10 of 18
3/5/13 at 8:48am
Something is amiss here...


1. As far as LS goes, I was working off this in your first post: "The vertical range is 45% of the image's height." The resulting LS from that figure is 24" of with a 110" screen.

Nearly doubling it (lens shift) yields nearly 20 more inches of shift to ~43" (it is indeed 80% of image height, btw).

2. What's 16.2" above or below the screen? The center-line of the image? Ok.

3. Agreed.

4. Ok.

5. Ok.

6. Still, I calculated 43" of shift (54 x .8 = 43.2") coupled with the 5 /12" drop/off-set so you can take it down (the image center) 48.5" of the needed 60' from the ceiling, meaning you'd need 11.5" if you were going to maximize the LS.

7. Would not a 1 1/2 - 2 foot extension be in order if you really wanted to stay away from the max of the LS?


This was all thrown off with the initial LS spec that ended up being about half the value it actually was.


Now that we have this figured out...


Good luck OP! biggrin.gif


James
Edited by mastermaybe - 3/5/13 at 8:54am
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post #11 of 18
3/5/13 at 9:46am
7. Would not a 1 1/2 - 2 foot extension be in order if you really wanted to stay away from the max of the LS?

Yes absolutely...however aesthetically a long pipe is not that pleasing and the longer the pipe the more sensitive the projector is to room vibrations...so there are +/-'s to either scenario.
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post #12 of 18
3/5/13 at 9:54am
Ok- I don't necessarily disagree with you, I just thought you were suggesting a foot long pipe under the assumption that he only needed ~8" to max out the LS when it's closer to a foot. I'm not an expert on how much light/image "damage" occurs as you get to the end of the this PJ's LS so I figured the more inches, the better in those respective depts, with another 6-12" not really mattering a whole lot in the grand scheme of things aesthetically with 10' ceilings.

I'm still wondering it it would be easier/cheaper to simply mount a shelf on the back wall and place it there, but I didn't see the mount , it could be inexpensive and quite easy to install.

James
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post #13 of 18
3/5/13 at 9:55am
Quote:
Originally Posted by leckian View Post

7. Would not a 1 1/2 - 2 foot extension be in order if you really wanted to stay away from the max of the LS?

Yes absolutely...however aesthetically a long pipe is not that pleasing and the longer the pipe the more sensitive the projector is to room vibrations...so there are +/-'s to either scenario.

One caveat this assumes that the lens horizontal position L-R is dead center. If you use the horizontal lens shift it will reduce the range of the vertical lens shift.
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post #14 of 18
3/5/13 at 11:06am
Yep. Hopefully he's able to get that pretty close right off the bat.

James
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post #15 of 18
3/18/13 at 5:39am
Thread Starter 
All,

thanks for all the input on this. Here is what i ended up with.

B&H sent me the wrong adapter so after wrangling with them I ended up with a slanted ceiling mount, installed sideways to allow for both Lag bolts to hit the same joist. That along with the adapter dropped the projecttor down 9" from the ceining. The Bottom of the screen is 29" from the floor, the screen height is 64", so the top of the screen is 93". Roughly the projector lens is less than 2 feet above the top of the screen. Should i drop it even further? will there be an apprciable difference in brightness? I currently have the projecotr in a nose down configuration to approximately the center of the screen. Is this a no no? I want to make sure i get this installed in the best possible position.

BTW, i brought the 3" down pipe to Lowes and asked them if they had a pipe of the same threads that would work. They claimed it was a special threading. Is that true? Has anyone else used a hardware provided down pipe with a Cheif adaptor?

Thanks for any help.
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post #16 of 18
3/18/13 at 10:06am
Thread Starter 
and yes, the projector is dead center
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post #17 of 18
3/18/13 at 10:13am
Quote:
Originally Posted by RickFinn View Post

All,

thanks for all the input on this. Here is what i ended up with.

B&H sent me the wrong adapter so after wrangling with them I ended up with a slanted ceiling mount, installed sideways to allow for both Lag bolts to hit the same joist. That along with the adapter dropped the projecttor down 9" from the ceining. The Bottom of the screen is 29" from the floor, the screen height is 64", so the top of the screen is 93". Roughly the projector lens is less than 2 feet above the top of the screen. Should i drop it even further? will there be an apprciable difference in brightness? I currently have the projecotr in a nose down configuration to approximately the center of the screen. Is this a no no? I want to make sure i get this installed in the best possible position.

BTW, i brought the 3" down pipe to Lowes and asked them if they had a pipe of the same threads that would work. They claimed it was a special threading. Is that true? Has anyone else used a hardware provided down pipe with a Cheif adaptor?

Thanks for any help.

I have used regular 1.5" plumbing nipple with Chief mounts with no problem. The projector should be level...to whatever extent it is not level it will introduce a trapezoid shape to your picture. If it is just a small tilt then it really should not be a problem as you can square off your picture by over zooming slightly and have a little of the image on the the black border of the screen. You may not notice any lose of brightness in using maximum lens shift...just try it and see if you perceive any difference.
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post #18 of 18
3/20/13 at 8:04am
Thread Starter 
OK, one more question and i hope i am done

Is it important for the projector to be as close to the height of the top of the screen as possible? does that help with performance?
and is it important that the projector body be as level as possible? like i said, i am dead center with the screen, although above it, I have about a 15-20 degree incline to point down at the screen, so to make this beter, i should get a down pipe long enogh to get close to the top of screen height and then be as level as possible on the projector.

is that the best scenario?
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