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Question about DNP 23-23 material screen

post #1 of 26
Thread Starter 
So i have some test patterns of the 23 material, and what i am noticing, when i move the patterns to the edges of the screen, it dims darker than the picture on just a white wall. I am trying to figure out if i just am projecting the test angle wrong


basically the test setup was Epson 5020 on a coffee table, maybe 7-8 feet from the screen. Screen projected was about 110in


the middle of the picture was nice and bright.


I guess my next question is what is the idea setup here. We want to ceiling mount this, but we need to get the angle right so that nothing dims here. Is this possible and what can i do to have a solid bright screen without this drop off in brightness towards the sides.
post #2 of 26
Is that short projection distance what you intend to use?

It creates greater angles between the projected light rays and the screen and consequent gain droppoff.

Same with a viewer close to the screen.
post #3 of 26
Thread Starter 
its up in the air to be honest as to how it gets positioned... but viewing distance is not going to be more than 10 feet at most. The projector will be on the ceiling but i can put it as far back as i need to to keep the light from dropping off.. is that possible considering we want 110in screen and sit no further back than 10 feet ? Closer viewing distance if possible with that Epson 5020

what do you think ?
post #4 of 26
from what I understand the minimum recommended throw distance for the 23-23 material is 1.8 throw ratio. Projecting onto a 110 inch from 7-8ft is way to close. I would say you will need to have the projector back atleast 13ft...even at 13 ft on 110 inch screen your not hitting the 1.8 throw ratio
post #5 of 26
Oh and the ideal setup is hard to say without knowing how high your ceiling is. I have a 9ft ceiling and the top of my projector lens is 18 inches down from the ceiling. So my screen at the very top is 18 inches from the ceiling.
post #6 of 26
Thread Starter 
Quote:
Originally Posted by natas777 View Post

from what I understand the minimum recommended throw distance for the 23-23 material is 1.8 throw ratio. Projecting onto a 110 inch from 7-8ft is way to close. I would say you will need to have the projector back atleast 13ft...even at 13 ft on 110 inch screen your not hitting the 1.8 throw ratio

so lets say throw moves back to 13ish feet..but viewing distance is still 7 feet...will the dimming improve or you need to sit back further for viewing as well ?
post #7 of 26
I think what you are seeing is hot spotting. Yes it will get better at 13ft compared to 7ft. However I personally think sitting 7-8ft from a 110 inch screen is way to close. I have a 106 inch screen and sit 14 ft. I am moving to a 110, I figured 120 would be to large at 14ft.
post #8 of 26
Quote:
Originally Posted by natas777 View Post

I think what you are seeing is hot spotting. Yes it will get better at 13ft compared to 7ft. However I personally think sitting 7-8ft from a 110 inch screen is way to close. I have a 106 inch screen and sit 14 ft. I am moving to a 110, I figured 120 would be to large at 14ft.

Seating distance depends on what you are going for... If your intention is an immersive theater-like experience, 14ft is not too close for a 120" screen (check the sticky thread in this forum for theater standards & recommendations). For a living room, it may be overwhelming. I tend towards making sure the screen is no smaller than the THX max allowed viewing distance at my farthest seat and no larger than a 15 degree angle from the front-row eyes to the top of the screen when eye level is 1/4-1/3 from bottom of screen... Works out to 133" from 14.5ft for my front row. Others like even larger, but I get dizzy in action scenes much closer than that. Where do you sit when you go to a theater?
post #9 of 26
Thread Starter 
Personally i like to sit in the middle when i go to the theater, but for 3d movies at home on 111in, i like to sit about 6-8 feet if possible... it does not hurt my head at all, i feel really in the movie, it all works out.

I just think that that may be too close to allow the 23 material to not dim ( or hotspot as you call it ) towards the edges ( hotspot in the middle i suppose that would be )


even if i pull the projector back to around 13 feet... i dont know if that will help the angle being reflected... you guys claim it will so i may try that just to see.
post #10 of 26
if you are truly concerned about the hot spotting then I would suggest you go with a throw ratio of 1.8 as this is there minimum. My guess is the 1.8 ratio is what they recommend to have minimal hotspotting and shimmering.
post #11 of 26
Thread Starter 
Quote:
Originally Posted by natas777 View Post

if you are truly concerned about the hot spotting then I would suggest you go with a throw ratio of 1.8 as this is there minimum. My guess is the 1.8 ratio is what they recommend to have minimal hotspotting and shimmering.

just to understand this concept better... when you say 1.8 throw ratio... this is only affected by projector distance and NOT viewing distance? OR i would need to adjust my viewing distance also?
post #12 of 26
that is the recommended throw ratio for the projector to screen
post #13 of 26
Thread Starter 
Quote:
Originally Posted by natas777 View Post

that is the recommended throw ratio for the projector to screen

I guess i dont know what a throw ratio is and that is my problem, lol


so at that distance of throw, i can sit anywhere i want you are saying 6-10+ feet viewing distance would all be fine ?
post #14 of 26
http://www.bambooav.com/throw-distance-and-throw-ratios-explained.html

Your distance you sit shouldn't matter to much. Although I would think sitting closer would cause you to see things like shimmering more than if you were further away.
post #15 of 26
Thread Starter 
I dont care about shimmer at all, i just want the brightness of the whole screen to be uniform.
post #16 of 26
Quote:
Originally Posted by tothjm View Post

so lets say throw moves back to 13ish feet..but viewing distance is still 7 feet...will the dimming improve or you need to sit back further for viewing as well ?

Try it and see
Quote:
Originally Posted by tothjm View Post

just to understand this concept better... when you say 1.8 throw ratio... this is only affected by projector distance and NOT viewing distance? OR i would need to adjust my viewing distance also?

Correct; throw ratio is the ratio of projection distance to screen width.

Sitting farther back will help because the angle froim a viewer to the edges of the screen is less, putting you at a higher point on the gain curve.
post #17 of 26
Thread Starter 
Quote:
Originally Posted by noah katz View Post

Try it and see
Correct; throw ratio is the ratio of projection distance to screen width.

Sitting farther back will help because the angle froim a viewer to the edges of the screen is less, putting you at a higher point on the gain curve.

thanks for the info


ideally as close to 7-8 feet viewing distance as i can get, the happier i will be. I will have my buddy try this setup as he is the one having issues. I will maybe get over there this weekend and give this a try just to see what happens smile.gif Thanks for all of your input!
post #18 of 26
Quote:
Originally Posted by natas777 View Post

if you are truly concerned about the hot spotting then I would suggest you go with a throw ratio of 1.8 as this is there minimum. My guess is the 1.8 ratio is what they recommend to have minimal hotspotting and shimmering.

Quote:
Originally Posted by tothjm View Post

just to understand this concept better... when you say 1.8 throw ratio... this is only affected by projector distance and NOT viewing distance? OR i would need to adjust my viewing distance also?

Correct, has to do with throw distance. The throw ratio is to minimize the hot spotting. You had the projector so close that there was a big drop off from the middle to the edges, because of the big hot spot you created in the middle of the screen. Image will look much more uniform if you use the 1.8 throw ratio for setting up the projector. So for your 96" wide screen you are looking at 14.4'.
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post #19 of 26
Thread Starter 
Quote:
Originally Posted by AV Science Sales 5 View Post


Correct, has to do with throw distance. The throw ratio is to minimize the hot spotting. You had the projector so close that there was a big drop off from the middle to the edges, because of the big hot spot you created in the middle of the screen. Image will look much more uniform if you use the 1.8 throw ratio for setting up the projector. So for your 96" wide screen you are looking at 14.4'.


Did you mean to say 110in ? I have a 110in picture I am testing smile.gif

assuming i use the exact ratio it suggests, should this 100% make the picture brightness uniform? Or i would need to push it back even more?
post #20 of 26
A 110" diagonal screen is about 96" wide
post #21 of 26
Thread Starter 
Quote:
Originally Posted by Will Binegar View Post

A 110" diagonal screen is about 96" wide

ah right i read that incorrectly! thanks guys i will test it this weekend and see if we can see any difference here.

now is the 1.8 ratio suggesting that if you place the proejctor at that correct distance, it should be 100% uniform as far as brightness ?
post #22 of 26
How is the sparkle on the DNP HG? I'd like to see that screen before I purchase. I'm leaning towards BD since ill have some sconces on the sides of the room while watching sports.
post #23 of 26
Quote:
Originally Posted by tothjm View Post

Did you mean to say 110in ? I have a 110in picture I am testing smile.gif

assuming i use the exact ratio it suggests, should this 100% make the picture brightness uniform? Or i would need to push it back even more?

100%? No screen will be 100% uniform. Neither will any projector. At the minimum throw ratio specified, it should have good, (acceptable) uniformity.
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post #24 of 26
Hi Folks,

I'm owner of Panasonic PT-AT6000E (PT-AE8000 US version) and for the last couple of months I have been looking for an ambient light screen.

I have decided to go with DNP, but can't decide whether I should opt for 08-85 or 23-23 material.

Throw distance will be at 13 ft. on either a 120" or 110" screen.

My goal is to be able to watch TV with controlled daylight or ambient room light. As I have complete light control I prefer to turn the living room to a bat-cave for movies or 3D.

If anyone has experience with DNP screens with Panasonic PT 8000/6000, I would like to get your insight on below questions.

1) At present with a standard white wall I can only enjoy 3D on Normal mode. How would 0.8 gain 08-85 material perform for 3D?
2) Would on 23-23 material picture "pop" too much in a bat-cave environment even on Eco Mode / Rec709?

Everyone agrees ISF certified 08-85 is better in contrast and no-hotspotting, but I have a feeling 3D may suffer on it.

Any experience you can share with DNP/Panny pairing with either 08-85 or 23-23, 2D/3D is highly appreciated!
post #25 of 26
post #26 of 26
Quote:
Originally Posted by tothjm View Post

ah right i read that incorrectly! thanks guys i will test it this weekend and see if we can see any difference here.

now is the 1.8 ratio suggesting that if you place the proejctor at that correct distance, it should be 100% uniform as far as brightness ?

Did you buy the DNP supernova HG-23?
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