New High Contrast High Power Discussion Thread - Page 11 - AVS Forum | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
Reply
 
Thread Tools
post #301 of 429 Old 12-18-2012, 04:37 PM
AVS Special Member
 
airscapes's Avatar
 
Join Date: Dec 2008
Location: Philadelphia
Posts: 5,022
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 174
To see the hchp drop off, just order a sample of hchp and hp, hangem on your screen and look.. it is very obvious.

Doug
Planar PD8150 paired with a Dalite HP 2.8 110"
http://www.airscapesart.com

 
airscapes is online now  
Sponsored Links
Advertisement
 
post #302 of 429 Old 12-18-2012, 07:16 PM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by airscapes View Post

To see the hchp drop off, just order a sample of hchp and hp, hangem on your screen and look.. it is very obvious.


I agree; noticed it pretty substantially even though I sit right at screen center, and the pj is centered and projecting just over my head, at closest throw.     That's why I choose to go with the regular HP2.4, and have been very pleased.

 

However I do have a fully light controlled room, with no ambient light issues; so didn't have to try to manage with the HC version.

millerwill is offline  
post #303 of 429 Old 12-18-2012, 11:23 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by millerwill View Post


I agree; noticed it pretty substantially even though I sit right at screen center, and the pj is centered and projecting just over my head, at closest throw.     That's why I choose to go with the regular HP2.4, and have been very pleased.

However I do have a fully light controlled room, with no ambient light issues; so didn't have to try to manage with the HC version.

Well, if you look at my traces of HCHP (grey) vs HP (black) for the upper left/right corners vs. the center from my center seating position, you can see that the HCHP doesn't drop off any more than the HP:



Now, this is in *my* setup (110' screen, 15' throw, 12' seating distance), so I understand YMMV. But it doesn't seem to me that the materials are that different within a reasonable viewing cone. The HCHP is, of course, lower gain throughout the entire screen (contrary to what the 2.4 gain rating would have you believe... actually on axis, center, I measured 2.9 gain over the Elite 1.1 screen for the HP & 2.7 for the HCHP).

However, I do agree that the off-axis gain does drop precipitously for HCHP. I shot some samples of HCHP & HP squares overlaid on top of an Elite Matte White (1.1 gain) screen from pretty far off-axis.

HCHP:


HP:


Here are the gains (calculated by dividing HP or HCHP signal by Matte White signal for any given portion of the screen) of the HP vs HCHP material as a function viewing angle (leftmost, center, & rightmost patches had viewing angles of 35º, 40º, and 50º, respectively, to my camera):



Here are the raw signals quantitated for the patches of HP, HCHP, and the Matte White 1.1 gain material:



You'll see that, for whatever reason, the Matte White screen itself drops precipitously for the right-most patch... some of this is due to the projector's vignetting, I know, but I don't know why it drops off faster than the HP/HCHP materials for that rightmost patch. For that reason, the calculated gain for the HP/HCHP materials actually increases for the rightmost patch relative to center. But it's slight, at any rate.

So, essentially, here's what we have for 40º off-axis gain:

HP: 0.85
HCHP: 0.65

Guess I'm no longer that surprised at the drop in gain to ~0.5 for the HCHP material. Hmm, not ideal. Re-thinking my decision to get the HCHP. In previous tests I did find its ability to reject ambient light better (duh). In other words, it maintained a higher actual contrast (brightest white/blackest black) than a HP patch in a scenario where the 120" Matte White 1.1 screen was scattering white light everywhere in my not-so-light-controlled room (white ceilings, light walls/floors). Here are my numbers for contrast gained by HP vs HCHP screens (over the Matte White screen) amidst light scatter from Matte White 1.1 screen:

HP: 2.2x more contrast than Matte White 1.1 screen
HCHP: 2.5x more contrast than Matte White 1.1 screen

Note this is a worst-case scenario: a completely white scene with one small black patch. In fact, my raw contrast numbers for this scene were:

Elite Matte White 1.1: 15.4
HP: 33.9
HCHP: 38.4

As is often the case, it's one big optimization problem smile.gif
sarangiman is offline  
post #304 of 429 Old 12-19-2012, 12:34 AM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56

When I compare the falloff curves of the HP2.4 and the HCHP2.4, I see that their falloff is fairly close out to ~ 15 deg, and then the HCHP falls off much more rapidly than the HP, going down to  ~0.5 and ~1.0, respectively, by ~ 35 deg.  

millerwill is offline  
post #305 of 429 Old 12-19-2012, 10:05 AM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
Da-Lite provided another curve, but it is for the 2.8HP... have requested the 2.4 HP as well...



and the previously posted HCHP for reference:

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #306 of 429 Old 12-19-2012, 11:11 AM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56

Thanks, dougri; very useful!    So at wider angles (>/=35 deg) the old HP2.8 falls to ~ 0.75 gain, the new HP2.4 to ~ 1.0, and the HCHP2.4 to ~ 0.5.    The is consistent with Dalite's description of the new HP2.4 having better gain at wider angles than the original HP2.8; but the HCHP has less.

millerwill is offline  
post #307 of 429 Old 12-19-2012, 01:47 PM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
And finally, all three curves straight from the horse's mouth (albeit the 2.4HP without tagged values):

Older High Power 2.8:


Newer High Power 2.4:


and High Contrast High Power 2.4:

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #308 of 429 Old 12-19-2012, 03:37 PM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
Composite Chart for Reference/Comparison:
sarangiman likes this.

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #309 of 429 Old 12-19-2012, 03:44 PM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
So, from this, I guess I can conclude if all my seating is within 20 degree viewing angle and I've got light walls and windows that the HCHP is probably the best choice between the newer HPs? And if you have seats out past 20 degrees viewing angle that are important, than the HP2.4 is the right choice? For those without ambient light issues, and seats within 15 degrees viewing angle, the original HP2.8 is the clear winner for brightness addicts. Sound like good rules of thumb? Of course, when you have the PJ either far in front or behind the viewing position, screen uniformity comes into play as well... pretty quickly for seats away from screen center (which would presumably favor the newer HP2.4).
sarangiman likes this.

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #310 of 429 Old 12-19-2012, 04:07 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Thanks a ton dougri!

All this makes a lot of sense to me. Initially I saw no problem with the HCHP vs. the HP b/c I was measuring from within a reasonable viewing cone. When I started making comparisons well outside of this cone is when I suddenly noticed dramatic drops in brightness for the HCHP.

For example, here's my calculations of gain from RAW photos I shot (vs. an Elite Matte White 1.1 gain screen, which was used as the reference to divide the HCHP/HP signals by) for the upper left corner (-10 on x-axis), center (0 on x-axis), and upper right corner (+10 on x-axis) viewed from the center seating position:



As you can see, the gains don't really change much between HCHP & HP for the corners. So the HCHP is not causing any additional vignetting compared to the HP. The HCHP does, however, have a lower gain in my setup... maybe b/c the projector is a little off-center & above my head?
sarangiman is offline  
post #311 of 429 Old 12-19-2012, 04:31 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
The reason I wanted to go with the HCHP was b/c of its (potential) ability to reject ambient light. Not light coming from windows & such, but just reflections off side walls & ceilings.

So I wanted to quantitate just how much it can help. Here's a little experiment I ran:

I made a 1080p file in Photoshop that was mostly white, with a black bar on bottom. I projected this onto a 110" HCHP screen, onto which HP patches were strategically placed in the center (amidst the white) & along the bottom bar (amidst the black). This way I could quantify the contrast each of these materials could maintain by taking the white & dividing it by the black.

Picture of my test (brights have been dimmed & darks have been brightened for ease of viewing):


I averaged a small square patch (same size patch for all samples) of pixels within the white/black HP squares, & within regions just to the left of these HP squares for the HCHP white/black measurements. Here are my raw numbers (pretty reliable as this is RAW capture which is mostly linear, within a certain range anyway):

HP White/Black = 4806/55 = 87.4
HCHP White/Black = 4070/43 = 94.7

So, the HCHP maintains better contrast.

Put another way, if we compare the blacks, the HCHP reaches 43/55 = 78% the black level of HP.

Guess that's not entirely trivial? The question is if you wish to sacrifice viewing cone for this enhanced black level in rooms that are not well light-controlled.

Would appreciate any thoughts/feedback. My HCHP screen arrives tomorrow & I can swap out just the material for HP for a reasonable fee within the first 30 days.
sarangiman is offline  
post #312 of 429 Old 12-19-2012, 05:08 PM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by dougri View Post

So, from this, I guess I can conclude if all my seating is within 20 degree viewing angle and I've got light walls and windows that the HCHP is probably the best choice between the newer HPs? And if you have seats out past 20 degrees viewing angle that are important, than the HP2.4 is the right choice? For those without ambient light issues, and seats within 15 degrees viewing angle, the original HP2.8 is the clear winner for brightness addicts. Sound like good rules of thumb? Of course, when you have the PJ either far in front or behind the viewing position, screen uniformity comes into play as well... pretty quickly for seats away from screen center (which would presumably favor the newer HP2.4).


I tend to agree with your conclusions:   if ambient light is a serious consideration, then one should really check out the HCHP.    If not, I think the HP is clearly better.

 

I found this out myself about a yr ago when I replaced my HP2.8 for a larger screen.     I thought I wanted to go with the new (at that time) HCHP, and ordered samples of it and the also new HP2.4.    Much to my surprise, I found the HCHP samples placed at the furthest left and right sides of what my new screen was planned to be (12 ft wide, viewed from ~ 12 ft away) were considerably dimmed compared to samples at the central part of the screen.   (This is likely due to the very large screen and close viewing distance, which leads to fairly wide viewing angles even though I sit at the lateral center of the screen.)   With the HP2.4 (non-HC) samples there was essentially no dimming.    Since I have no ambient light to worry about (and also light absorbing material on ceiling and side walls out ~ 8 ft from the screen wall), I thus made the obvious choice for the non-HC HP2.4.     I find that it gives extremely uniform brightness over the whole screen.

 

The morale to my experience is that one can be guided by these very useful figures, but BE SURE to order samples from Dalite and put them up at the extreme positions of the screen you are planning for to be sure.

millerwill is offline  
post #313 of 429 Old 12-20-2012, 08:53 AM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
Quote:
Originally Posted by millerwill View Post


I found the HCHP samples placed at the furthest left and right sides of what my new screen was planned to be (12 ft wide, viewed from ~ 12 ft away) were considerably dimmed compared to samples at the central part of the screen.   (This is likely due to the very large screen and close viewing distance, which leads to fairly wide viewing angles even though I sit at the lateral center of the screen.)   With the HP2.4 (non-HC) samples there was essentially no dimming.

I find that it gives extremely uniform brightness over the whole screen.

The morale to my experience is that one can be guided by these very useful figures, but BE SURE to order samples from Dalite and put them up at the extreme positions of the screen you are planning for to be sure.

If you don't mind my asking, what is your throw in comparison to your viewing distance? Your experience is consistent with what you would expect from a retroreflective screen as the viewing distance and throw distance diverge... and the effect becomes apparent more quickly with the HCHP. In the unrealistic, ideal case of the PJ lens being at your eyes, the gain will be the same across the entire screen... as you move the projector in any direction from that point, there will start to be variations is screen gain determined largely by the angle between: 1) the line connecting the PJ lens with a given point on the screen, and 2) the line connecting an eye and that same point on the screen (yes, there will be a minor, imperceptible difference in gain between each eye). Did you try viewing the HCHP from very near the projector lens? I'd expect very uniform brightness in that case for all the HP screens... with differences becoming rapidly apparent as you move away from the PJ lens in any direction (up/down, forward/back, right/left).

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #314 of 429 Old 12-20-2012, 09:24 AM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by dougri View Post


If you don't mind my asking, what is your throw in comparison to your viewing distance? Your experience is consistent with what you would expect from a retroreflective screen as the viewing distance and throw distance diverge... and the effect becomes apparent more quickly with the HCHP. In the unrealistic, ideal case of the PJ lens being at your eyes, the gain will be the same across the entire screen... as you move the projector in any direction from that point, there will start to be variations is screen gain determined largely by the angle between: 1) the line connecting the PJ lens with a given point on the screen, and 2) the line connecting an eye and that same point on the screen (yes, there will be a minor, imperceptible difference in gain between each eye). Did you try viewing the HCHP from very near the projector lens? I'd expect very uniform brightness in that case for all the HP screens... with differences becoming rapidly apparent as you move away from the PJ lens in any direction (up/down, forward/back, right/left).


Your analysis is exactly right:   the relevant angle is that from the pj lens to a point on the screen, and from that point to your eye.

 

My projector (Sony1000ES) has a very small min throw ratio (1.27), and I'm right at that limit.   So for my 12ft wide screen the pj lens is a bit over 15 ft from the screen.    And I sit close (~12 ft from screen), so the angle I describe above is ~20 deg (IIRC) to points on the screen at the L and R edges; the angle is obviously 0 deg for points at the center of the screen.     And just as you suggest, that is the reason for the brightness falloff I observe with the HCHP.     If I move my chair further back, e.g., to ~ 14 ft, and thus have my eyes closer to the pj lens, then the brightness is uniform over the whole screen.    

 

But I like to sit close, for the 'total immersion' feeling.    Ideally, I would like a projector with a min throw ratio of 1.0; then I could sit at my desired 1.0 SW distance and have the pj just behind (and just above) my head.   The HCHP would work for me in that case.   

 

PS   Just re-did the calculation, and the angle for points at the L & R edges of the screen is only 5 deg.   According to the graphs you showed, this would give a gain of ~2.0 with the HCHP, and ~ 2.2 with the HP, both having a gain of 2.4 for points at the center of the screen.    As I noted in a previous post, the safest way to decide is to get samples of each material from Dalite, tape them up on the wall at various positions on the prospective screen, to check for brightness variation.

millerwill is offline  
post #315 of 429 Old 12-20-2012, 11:21 AM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by millerwill View Post

PS   Just re-did the calculation, and the angle for points at the L & R edges of the screen is only 5 deg.   According to the graphs you showed, this would give a gain of ~2.0 with the HCHP, and ~ 2.2 with the HP, both having a gain of 2.4 for points at the center of the screen.    As I noted in a previous post, the safest way to decide is to get samples of each material from Dalite, tape them up on the wall at various positions on the prospective screen, to check for brightness variation.

In my experience, the HP always has a higher gain than the HCHP. If you post a HCHP & HP patch next to each other on the center of the screen, isn't the HP brighter? It is for me. You guys seriously don't see this?

Within my center seating position, sitting 1.25x screen width away from the 110" (diagonal) screen, there's absolutely no difference in fall-off (at corners) for HCHP vs. HP.
sarangiman is offline  
post #316 of 429 Old 12-20-2012, 01:55 PM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
Quote:
Originally Posted by sarangiman View Post

In my experience, the HP always has a higher gain than the HCHP. If you post a HCHP & HP patch next to each other on the center of the screen, isn't the HP brighter? It is for me. You guys seriously don't see this?
Within my center seating position, sitting 1.25x screen width away from the 110" (diagonal) screen, there's absolutely no difference in fall-off (at corners) for HCHP vs. HP.

I'd be interested to know your exact setup to see just how accurate the gain charts are compared to your experience... from my rough calculations with the PJ behind the viewers and just high enough (or offset enough) to clear the viewers' heads, or the PJ just low enough to be out of the line of sight to the screen, the minimum angle between the closest viewer and the center of the screen is about 7 degrees.... which just happens to be the largest gain difference between HP and HCHP from 0-15 degrees. The difference in gain is a smidge more than 10% at 7 degrees... and they actually are much closer in gain at 15 degrees. Relative gain differences between screens are very noticable when placed side by side, and keep in mind, for a given screen, the difference in gain just due to the interocular distance of 2.5" is about .05

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #317 of 429 Old 12-20-2012, 02:09 PM
Advanced Member
 
dougri's Avatar
 
Join Date: Oct 2006
Posts: 935
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Liked: 35
What is interesting to me is that for seating within about 15 degrees, the HCHP might actually have better uniformity, albeit at slightly lower gain while doing a slightly better job with ambient light as well. For my living room, with the PJ on a pedestal behind an 'L' shaped sofa, and a second row of seating at barstools about 100" behind the PJ (and within 10 degrees viewing angle), the HCHP from the charts has better uniformity. I'll have to order some more samples and see if that bears out in reality. Certainly with larger viewing angles, the HCHP is pretty bad, but that may not bite me with my odd setup.

"A wide screen just makes a bad film twice as bad. "
-Samuel Goldwyn

I wonder what he'd think about 3D IMAX?
dougri is offline  
post #318 of 429 Old 12-29-2012, 10:44 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by dougri View Post

What is interesting to me is that for seating within about 15 degrees, the HCHP might actually have better uniformity, albeit at slightly lower gain while doing a slightly better job with ambient light as well. For my living room, with the PJ on a pedestal behind an 'L' shaped sofa, and a second row of seating at barstools about 100" behind the PJ (and within 10 degrees viewing angle), the HCHP from the charts has better uniformity. I'll have to order some more samples and see if that bears out in reality. Certainly with larger viewing angles, the HCHP is pretty bad, but that may not bite me with my odd setup.

Interesting. Yeah I also saw in one of my charts that technically the uniformity of the HCHP was slightly higher than the HP... but I just thought this might be error in measurements. It wasn't dramatic, at any rate.

My set up: my HW50 is just about 12" above eye level, sitting on a curio/bookshelf. 110" HCHP screen, sitting distance is 10ft (so 1.25x SW). Projector is slightly to the right behind my head, so I do need a little lens shift toward the left.

I just find it interesting that in most of my measurements, the HCHP is just a steady 0.2 lower than HP in gain. Except for my 50º viewing angle measurement, where it was 0.25 lower than the HP. Of course, HCHP's smaller viewing cone is exactly what allows it to reject more stray light, so I still think it can be useful. I find myself generally wanting blacker blacks for bright scenes, which is when room reflections kill the contrast. I don't care too much about the narrow viewing cone since it appears that for the a row of 4 people sitting on my couch, the drop-off on either end of the couch is the same for HP as HCHP... just that the overall gain is lower. And the only time I care about 0.2 lower gain is for 3D; the Sony projector is bright!

Fun stuff, and thanks for some of those numbers/calculations, dougri. Happy Holidays!
sarangiman is offline  
post #319 of 429 Old 01-01-2013, 07:09 PM
AVS Addicted Member
 
noah katz's Avatar
 
Join Date: Apr 1999
Location: Mountain View, CA USA
Posts: 21,015
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 559 Post(s)
Liked: 217
Quote:
Originally Posted by dougri View Post

...screen gain determined largely by the angle between: 1) the line connecting the PJ lens with a given point on the screen, and 2) the line connecting an eye and that same point on the screen ...

Is this the angle used in Dalite's gain curves, or is it just the angle between a perpendicular through the center of the screen and an off-axis viewing position?

Noah
noah katz is offline  
post #320 of 429 Old 01-01-2013, 08:02 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Update: I received my HCHP screen & put it up. It has a really distracting texture that shows up as vertical & horizontal striations across the entire screen. Visible in pans with skies, and especially visible when playing video games (since there's constant motion & a general lack of contrast/fine detail in a lot of games). Ugh. Did they never fix this problem? Is it even possible to get a HCHP screen without these problems?

Also makes me wonder-- does the HP screen have these striations as well, just harder to see b/c it's brighter?

Are the striations due to the gray, or the little beads? It's weird that it's mostly horizontal & vertical... must be a remnant of some coating process.

Otherwise, it's gorgeous. I actually decided I like the fact that it has really bad gain at extreme angles... b/c this means that my ceilings & walls near the screen just get much less light than they would with a HP screen. And since I decided the black velvet curtains around the screen were just too ugly, I need a screen like the HCHP.

If anyone's curious, for a completely white image with a small black square (i.e. worst-case light scattering scenario):
  • At the center of the screen: without the curtains I get 92% the contrast I get with curtains
  • At the edges of the screen: without the curtains I get 82% the contrast I get with curtains (more contrast cost at edges b/c they're closer to the ceiling or wall)

Meanwhile, I get a 333% boost in contrast (for this worst-case completely bright scene scenario) just going from the matte white 1.1 scree to the HCHP.

So... meh. I hate the curtains, so am taking a contrast hit smile.gif

Happy New Year!
sarangiman is offline  
post #321 of 429 Old 01-02-2013, 04:54 AM
AVS Special Member
 
airscapes's Avatar
 
Join Date: Dec 2008
Location: Philadelphia
Posts: 5,022
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 168 Post(s)
Liked: 174
Don't settle for distracting lines and texture.. get on the phone today and start screaming!

Doug
Planar PD8150 paired with a Dalite HP 2.8 110"
http://www.airscapesart.com

 
airscapes is online now  
post #322 of 429 Old 01-02-2013, 11:54 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by airscapes View Post

Don't settle for distracting lines and texture.. get on the phone today and start screaming!

Ha. Well I don't think screaming helps :-P But I did call up Da-Lite & the dealer & they'll swap out the screen for either HCHP or HP. My dilemma is: do I keep swapping out HCHP screens until I get one without texture (does a HCHP screen without texture even exist??), or do I just get a HP?

IF the HCHP actually has more of a gain drop-off at extreme angles than the HCHP, it's just going to send much less light at my walls/ceilings than the HP. Just look at how dark the HCHP patches look off-angle compared to matte white (1.1 gain):

HCHP patches on Matte White 1.1 screen:


Compare that to...

HP patches on Matte White 1.1 screen:


So, yeah... that's exactly what HCHP has going for it.

But here's what the texture on my HCHP screen looks like (contrast has been drastically exaggerated for you to see):

Link: http://cl.ly/LuTw/HCHP-Texture.jpg

Those vertical patterns you see are exactly what show up during viewing.

I'm wondering what the problem is. It's not like you can't make a grey screen without texture. What about a grey screen with microbeads is giving Da-Lite a hard time? Or do HP screens also have this sort of texture/pattern, just less easy to see due to it being so bright (doesn't really make sense, actually)?
sarangiman is offline  
post #323 of 429 Old 01-03-2013, 03:34 AM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Also, I did a quick HCHP vs. HP comparison tonight at extreme viewing angles to see how much better the HCHP is at scattering *less* light to extreme angles (i.e. stuff that'd hit walls/ceilings). I took measurements of an HP patch placed on top of the HCHP screen at the center, and took measurements of the HCHP material immediately to one side of the HP patch (not idea, but should be close enough).

Here's a graph of the ratio of HCHP to HP intensity at different viewing angles (measured with protractor):



Straight on, the HCHP shows ~84% the intensity of the HP. This is pretty much what I consistently see in my setup.

However, at 70º, the HCHP shows 69% the intensity of the HP. That's a 15% drop in comparative intensity between HCHP and HP as we moved from 0º to 70º viewing angle. I believe one could interpret this as meaning that the HCHP, compared to HP, may roughly scatter 15% less light to walls/ceilings at a 70º angle (in my setup, anyway). Do you agree? So this, in addition to its grey base, could help maintain better contrast in light-colored rooms.

The question is: is this 15% worth the headache of trying to find a HCHP surface without texture? smile.gif

P.S. I still, consistently, get different results from Da-Lite's numbers re: HCHP vs HP gain at different angles. They claim the HCHP drops to ~0.5 gain at extreme angles while HP maintains a gain of 1 even at those extreme angles. I actually see the HP material dip to lower than 1.0 gain even at 35º, and the HCHP never dips below ~69% the intensity of the HP. Again, the Da-Lite graphs would have you believe the HCHP drops to 50% the intensity of the HP at extreme angles... I just don't see it dipping that low in my setup/measurements.
sarangiman is offline  
post #324 of 429 Old 01-03-2013, 11:05 AM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by sarangiman View Post

Also, I did a quick HCHP vs. HP comparison tonight at extreme viewing angles to see how much better the HCHP is at scattering *less* light to extreme angles (i.e. stuff that'd hit walls/ceilings). I took measurements of an HP patch placed on top of the HCHP screen at the center, and took measurements of the HCHP material immediately to one side of the HP patch (not idea, but should be close enough).
Here's a graph of the ratio of HCHP to HP intensity at different viewing angles (measured with protractor):

Straight on, the HCHP shows ~84% the intensity of the HP. This is pretty much what I consistently see in my setup.
However, at 70º, the HCHP shows 69% the intensity of the HP. That's a 15% drop in comparative intensity between HCHP and HP as we moved from 0º to 70º viewing angle. I believe one could interpret this as meaning that the HCHP, compared to HP, may roughly scatter 15% less light to walls/ceilings at a 70º angle (in my setup, anyway). Do you agree? So this, in addition to its grey base, could help maintain better contrast in light-colored rooms.
The question is: is this 15% worth the headache of trying to find a HCHP surface without texture? smile.gif
P.S. I still, consistently, get different results from Da-Lite's numbers re: HCHP vs HP gain at different angles. They claim the HCHP drops to ~0.5 gain at extreme angles while HP maintains a gain of 1 even at those extreme angles. I actually see the HP material dip to lower than 1.0 gain even at 35º, and the HCHP never dips below ~69% the intensity of the HP. Again, the Da-Lite graphs would have you believe the HCHP drops to 50% the intensity of the HP at extreme angles... I just don't see it dipping that low in my setup/measurements.

Can you measure (or estimate) the angle between the two lines, one from the projector to a spot on the center of the screen, and from your eye to that same point?    I.e., even 'straight on', this angle will not be 0 because the pj is not exactly where your eye is.

millerwill is offline  
post #325 of 429 Old 01-03-2013, 02:54 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by millerwill View Post

Can you measure (or estimate) the angle between the two lines, one from the projector to a spot on the center of the screen, and from your eye to that same point?    I.e., even 'straight on', this angle will not be 0 because the pj is not exactly where your eye is.

The HP patch was placed pretty much right on axis with the lens. I, of course, had to shoot the 0º shot slightly off-axis... maybe like 5º? The other angle numbers should be accurate, as I used the protractor to measure the angle between the camera and the line normal to the HP patch; the latter being right on axis with the lens... so, I don't see how those numbers would be any different.
sarangiman is offline  
post #326 of 429 Old 01-03-2013, 04:02 PM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by sarangiman View Post


The HP patch was placed pretty much right on axis with the lens. I, of course, had to shoot the 0º shot slightly off-axis... maybe like 5º? The other angle numbers should be accurate, as I used the protractor to measure the angle between the camera and the line normal to the HP patch; the latter being right on axis with the lens... so, I don't see how those numbers would be any different.


OK, tx; you're probably right.    However, if you look at the gain curves (from Dalite, I believe), the ratio of the HPHC to HP gain at 5 deg is ~ .85 to .9, about what you reported above for the ratio of your 'straight on' measurement.

700

millerwill is offline  
post #327 of 429 Old 01-03-2013, 04:21 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by millerwill View Post


OK, tx; you're probably right.    However, if you look at the gain curves (from Dalite, I believe), the ratio of the HPHC to HP gain at 5 deg is ~ .85 to .9, about what you reported above for the ratio of your 'straight on' measurement.
700

Ah, good point. Thanks for pointing that out.

But my ratios don't hold for the rest of the viewing angles. Da-Lite says the HCHP drops to half the gain of the HP way off-axis; I only see at worst a drop-off of ~0.7, not 0.5. Maybe this is because of scattered light or who knows what!

Do you think 15% less scattered light at extreme angles is significant? Really hard to judge, I guess. I suppose I should just get the HP screen and quantitate what the worst case contrast is using my previous method I used for the HCHP screen (white screen with one small black square)... only problem is that I'd likely be stuck with the HP screen once I get it.
sarangiman is offline  
post #328 of 429 Old 01-03-2013, 05:18 PM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by sarangiman View Post


Ah, good point. Thanks for pointing that out.
But my ratios don't hold for the rest of the viewing angles. Da-Lite says the HCHP drops to half the gain of the HP way off-axis; I only see at worst a drop-off of ~0.7, not 0.5. Maybe this is because of scattered light or who knows what!
Do you think 15% less scattered light at extreme angles is significant? Really hard to judge, I guess. I suppose I should just get the HP screen and quantitate what the worst case contrast is using my previous method I used for the HCHP screen (white screen with one small black square)... only problem is that I'd likely be stuck with the HP screen once I get it.


OK, useful info; I agree that it's always good to check things out for your own situation rather than just accept published values.

 

Hard for me to say about the 15% difference you ask about.    In my case (but maybe not close enough to yours to be relevant--12 ft wide screen, viewed from ~ 12 ft), I noticed a significant brightness drop off at the L and R edges of the screen with the HPHC samples, even when sitting pretty much at screen center; with the HP samples the brightness was much more uniform out to the edges (as one would expect because of the wider viewing cone).   I thus decided to go with the HP material and have been extremely pleased with it; it is even smoother than an earlier HP2.8 screen that I had (but was smaller--the reason I replaced it!), which was already very good in this regard.

 

However I do have black absorbing material on the ceiling and side walls out to ~ 9 ft from the screen wall, so there is no issue at all from side wall or ceiling reflections.

 

One of the fun parts of setting up ones HT is the careful research and analysis that one must go through to find the most acceptable solution for their own specific situation.

millerwill is offline  
post #329 of 429 Old 01-03-2013, 05:26 PM
Advanced Member
 
sarangiman's Avatar
 
Join Date: Feb 2006
Posts: 542
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Liked: 20
Quote:
Originally Posted by millerwill View Post


OK, useful info; I agree that it's always good to check things out for your own situation rather than just accept published values.

Hard for me to say about the 15% difference you ask about.    In my case (but maybe not close enough to yours to be relevant--12 ft wide screen, viewed from ~ 12 ft), I noticed a significant brightness drop off at the L and R edges of the screen with the HPHC samples, even when sitting pretty much at screen center; with the HP samples the brightness was much more uniform out to the edges (as one would expect because of the wider viewing cone).   I thus decided to go with the HP material and have been extremely pleased with it; it is even smoother than an earlier HP2.8 screen that I had (but was smaller--the reason I replaced it!), which was already very good in this regard.

However I do have black absorbing material on the ceiling and side walls out to ~ 9 ft from the screen wall, so there is no issue at all from side wall or ceiling reflections.

One of the fun parts of setting up ones HT is the careful research and analysis that one must go through to find the most acceptable solution for their own specific situation.

Oh wow, you have like a ~165" diagonal screen (if it's 16:9)? Mine's only 8ft wide (110" diagonal), so no wonder I don't see any difference at the corners between the HCHP vs HP material, whereas you do!

9ft out! Wow! I only had curtains ~2ft out, which still helped quite a bit with contrast at the edges. Helped tremendously with the matte white screen; less so w/ the HCHP given it scatters much less light to begin with.

Sure I agree it's fun... to a certain point. But at this point with all the problems I've experienced (replacement of HW50 due to bad lens, new HW50 flickers, HCHP material has texture, etc.), it's quite frustrating to say the least. Furthermore, I move a lot, so it's no efficient for me to optimize for any one given scenario. So one may argue I'm trying to build a home theater experience in a space I shouldn't. Fair enough. So I'm just trying to optimize for the fact that I'll typically be in smaller spaces with lots of light-colored walls/ceilings. Hence why I went for the (relatively) smaller 110", and the HCHP material.

I just can't seem to find a way to make the black velvet around the screen look decent. I used rods sticking out 2ft from the screen on either corner, then attached the middle top portion of the velvet to the ceiling with small magnets (to create a 'draping' effect). Without the middle attachment, the velvet just drops too low (the two posts on the corners can't tension the fabric enough to keep it straight across the top of the screen). I feel like the only real solution is to paint the walls/ceilings nearby, or put dark tiles on them. Which is difficult for city condo living.
sarangiman is offline  
post #330 of 429 Old 01-03-2013, 06:08 PM
AVS Addicted Member
 
millerwill's Avatar
 
Join Date: Apr 2004
Location: Berkeley, CA
Posts: 11,502
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 88 Post(s)
Liked: 56
Quote:
Originally Posted by sarangiman View Post


Oh wow, you have like a ~165" diagonal screen (if it's 16:9)? Mine's only 8ft wide (110" diagonal), so no wonder I don't see any difference at the corners between the HCHP vs HP material, whereas you do!
9ft out! Wow! I only had curtains ~2ft out, which still helped quite a bit with contrast at the edges. Helped tremendously with the matte white screen; less so w/ the HCHP given it scatters much less light to begin with.
Sure I agree it's fun... to a certain point. But at this point with all the problems I've experienced (replacement of HW50 due to bad lens, new HW50 flickers, HCHP material has texture, etc.), it's quite frustrating to say the least. Furthermore, I move a lot, so it's no efficient for me to optimize for any one given scenario. So one may argue I'm trying to build a home theater experience in a space I shouldn't. Fair enough. So I'm just trying to optimize for the fact that I'll typically be in smaller spaces with lots of light-colored walls/ceilings. Hence why I went for the (relatively) smaller 110", and the HCHP material.
I just can't seem to find a way to make the black velvet around the screen look decent. I used rods sticking out 2ft from the screen on either corner, then attached the middle top portion of the velvet to the ceiling with small magnets (to create a 'draping' effect). Without the middle attachment, the velvet just drops too low (the two posts on the corners can't tension the fabric enough to keep it straight across the top of the screen). I feel like the only real solution is to paint the walls/ceilings nearby, or put dark tiles on them. Which is difficult for city condo living.

My screen is 12 ft W for 2.35 (and thus ~61" H); for 16x9 (actually 17x9 for my Sony VW1000) it is 136"x72".

 

The light absorbing material is ProtoStar material (used to line telescopes; check its website), and I attached with push pins since I first put it up temporarily, just to see how it would work; it worked so well that I've simply left it this way; very simple.    And yes it is REMARKABLE how much it enhances contrast, even if you have some external light (which I usually don't).       According to reports on the Forum, you get the major effect if it only goes ~ 4 ft from the screen wall, but in my room it made sense to bring to out further.   

 

With your size screen I understand that you don't have brightness falloff with the HPHC, so it is a more viable option for you.    However I do note that the HP2.4 material is EXTREMELY artifact-free; it is creamy smooth and just 'disappears'.    

millerwill is offline  
Sponsored Links
Advertisement
 
Reply Screens

Tags
Projection Screens

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off