New High Contrast High Power Discussion Thread - Page 13

What BobL says makes sense. I'd expect the HCHP to have a different coating than the HP since it has a narrower viewing cone. So maybe the beads do have a problem to begin with (even for HP), but are more problematic when you need a higher gain coating?

I'll try cleaning the screen tomorrow with ethanol & microfiber cloths, as airscapes suggested.

Has no one seen a Draper screen? Are they even well regarded?

I just learned in this thread http://www.avsforum.com/t/1449462/draper-contrast-radiant-vs-da-lite-high-contrast-high-power-hchp/0_50 that last year Draper introduced what many have wanted from Dalite - a gray high-gain (2.7) retroreflective screen

http://www.cepro.com/images/products/162_spec_sheet_OptiView_Contrast_Radiant_CH2700E.pdf

Um, yeah. That's my thread over there

And Da-Lite has had this HCHP screen for some time now. Clearly it's not very popular; possibly for good reason.

Btw, the HCHP screen I got is, in fact, extremely dirty. You can tell b/c if you wipe a small portion with denatured alcohol, it becomes brighter there. But it's really hard to wipe properly & get all the dirt/residue off. I really don't think this should be the buyer's job.

Despite the dirt/residue, the underlying streaking pattern still appears to be there. Sheesh. Fail.

He was probably referring to the higher gain (spec-wise the Draper CR seems like a grey 2.8HP instead of a grey 2.4HP)... just need more info/reviews.

Yes, the big news, at least to me, is the retroreflective Draper.

Ok. In my measurements, the Draper 2.7 grey (Contrast Radiant) has exactly the same gain as the HCHP 2.4, but I haven't measured the off-angle gains (Draper claims the Contrast Radiant has a half-angle of 15º, which I believe is more than the Da-Lite HCHP).

The Radiant 2.7 (white) actually has lower gain than the Da-Lite HP 2.4.

I'll post some pictures when I get a chance.

Interestingly, they are claiming 15 degrees as the "viewing cone", but it is certainly not the half-peak-gain point:

BTW, how does one measure peak gain on a retroreflective screen without blocking the projection?

Actually, seems to me they're claiming the half-gain angle is 15º, which it is, b/c at 15º you get a gain of ~1.25, which is roughly half of 2.7 (ok looks like they cheated a little & the half-gain angle should be 14º b/c that's where it's ~1.3). Which makes the viewing cone 30º.

If you look back at post 296 (your own post), the half-gain angle is 20º (Da-Lite lists the HCHP as having a 20º viewing half angle).
http://cdn.avsforum.com/6/66/66eaf78f_HCHP.PNG

So that'd mean the Draper Contrast Radiant has an even narrower viewing cone than the HCHP. In my shots, it seems to perform very similar to HCHP, but, again, I didn't compare them at all angles. I can try that later tonight... shooting the Contrast Radiant over the HCHP at various angles.

As for measuring peak gain: you're right, I can never quite measure 0º. But I get really close by standing right behind/above the projector & using a zoom lens. Honestly though it's probably more like a 5º viewing angle.

sarangiman,

So what do you think of the Draper's surface texture compare to the Dalite's?

I only have a small sample of the Draper. You can't tell anything from small samples. The small sample of HCHP looks fantastic! Not the 110" screen though.

As I mentioned earlier, there's not much 'sheen' or texture to the small samples (like there is for typical glass-beaded surfaces). In fact, I bet in a double-blind study you wouldn't be able to tell which sample is which... they look that similar to me.

I'm just curious if Draper screws it all up when you get to the full screen size. Also curious as to why Da-Lite is shipping hella dirty screens to begin with. My $350 Elite screen was worlds cleaner.

Interesting, thanks.

From some quick googling it looks like the Draper is 2-3X the price of HP, so one would expect better QC.

Have any links? I can't find any online reseller that lists the Draper Radiant/Contrast Radiant surfaces. Big Screen Center appears to be a sham...

Have you call AVS to see if they sell them?
I really don't understand why you just don't have Dalite send you another HCHP if you are bound and determined to have a gray screen.. you paid for it, and it is not made correctly.. it is defective and you should have it replaced.. The streaking aside, there is problems with the way it fits the frame in the 2 corners, that is not acceptable. Or are you going to send it back and get a full refund?

https://www.google.com/search?q=draper+ch2700e&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

if focusedtechnology is legit, their prices are pretty much in line with those for HP and a bit less than HCHP. Where do you see 2-3X the price for the same screen type (e.g. luma2 vs ModelC)?

sarangiman, how old is your HCHP screen? At the beginning of 2012 I too went through 3 HCHPs which had the exact same issues you are showing before switching to the regular 2.4 HP. It too had the problems but not as bad as the HCHP so I decided to keep it. About two months ago I decided to swap it out one more time with da-lite before my one year warranty was over. The new HP they sent me is perfect. No streaks, darker areas, anything. You might think about giving them a call and trying one more time. They might have fixed the issue. Either that or I just got extremely lucky!

Jesus. 4 swaps. Who has time/energy for that? Where's the QC?

And Noah, if anything, the Draper screens seem less expensive than the Da-Lite screens. Though I can't find any prices for the fixed frame (Onyx series) Contrast Radiant.

Also, I did a viewing angle test last night for the Draper vs. the Da-Lite. I put a patch of Draper Contrast Radiant over the center of my HCHP screen. According to Draper & Da-Lite's gain vs. viewing angle graphs, one would assume the Draper has a narrower viewing cone. For example, at a 20º viewing angle, the Draper Contrast Radiant apparently has a gain of ~0.75 while the HCHP has a gain of 1.2.

Well, turns out, in my own tests, the Draper Contrast Radiant has a similar, if not slightly larger, viewing cone compare to the HCHP, as it holds a similar/higher gain at all viewing angles than the HCHP. Edit: 1/11/13: This may be due to the fact that my HCHP screen is dirty.

Pics coming soon...
Edited by sarangiman - 1/11/13 at 12:03pm

Here's the evidence that the Draper Contrast Radiant actually has a similar or slightly wider viewing cone than the HCHP, despite the graphs provided by the respective companies (perhaps testing methodologies aren't standardized)... this shot was taken well off-axis; Draper Contrast Radiant sample is taped on top of my 110" HCHP screen:

Draper Contrast Radiant sample patch on top of HCHP screen:


I took a bunch of shots at various angles, moving from ~5º to ~90º. I did this for both a patch of Draper Contrast Radiant on top of the HCHP screen, as well as a patch of Draper Radiant on top of the HCHP screen. I shot RAW images then quantitated the brightness values (modest size squares were sampled for good averaging of pixels). Here is the data, below. 100% would mean equal brightness between HCHP and the enumerated Draper screen material. Less than a 100% means the HCHP is dimmer than the enumerated Draper material (90% means it's 90% as bright as the Draper material). You can see that the HCHP does fall off faster than the Draper Contrast Radiant, and obviously falls off much faster than the Draper Radiant (HP equivalent).



Please note the viewing angles are really rough estimates, so don't pay any attention to them. The general trend is that I went from 5º to 90º off the projector axis.

So, I don't trust the viewing cone numbers from the manufacturers, based on these samples/screens. Draper appears to be better. I'm in a good mind to try out a Draper screen... be the guinea pig, so to speak, since it seems literally no one on these forums have any experience with the Draper Radiant/Contrast Radiant screens...

Caveat: I don't know how much of the lower brightness values of the HCHP screen is due to being dirty...
Edited by sarangiman - 1/11/13 at 12:05pm

That would be great! No one has tired it because the HP was always the bomb with the happy campers (std HP not this HC thing). Now things have changed and even the quality of the HP is in the crapper, but so far, you are the first person who apparently can afford to just buy another screen rather than send back the defect for another. I know you don't want to spend a lot of time messing around with screens as you have said, but do you have enough room someplace in your home to do a side by side comparison of the Draper and Dalite if you buy another screen?
Edited by airscapes - 1/10/13 at 5:10am

focusedtechnology and nerds.net appear to carry the onyx line with 'veltex'... with the former pricing the 133" 16:9 @ $1359.

Ha! Uh, no. I was thinking of returning the HCHP screen altogether, since it's new. And trying the Draper. Not buying two screens.

The Draper seems to have a better tensioning system anyway, that I assume would never cause the ripples I'm seeing in the two locations due to the snaps on the Da-Lite.

I See, well we are all interested in how it turns out!

I was doing some sloppy googling and saw $3500 for an electric 147" (or whatever the next size is above 133"), vs. the $1300 I paid for a 62x128 HP electric.

Maybe the Draper was a fancy tensioned one or something.

sarangiman, your results are very odd, as it seems to defy physics that the CR has higher gain at all angles.

I took the liberty of overlaying Draper's own traces of their Radiant & Contrast Radiant gain vs. viewing angle curves. I then changed the colors of the traces/viewing angle diagrams for easy viewing:

Draper Radiant vs. Contrast Radiant



Now this is more like what I expect out of a white retroreflective vs. grey retroreflective screen, as long as each screen received roughly the same depth/number of reflective beads. The viewing cone should really only change (get narrower) if the grey retroreflective screen got more beads or has a higher gain coating over the grey.

The Draper screens look like they have about the same coating, just with a white or grey base (the gain curves literally only/mostly shift up/down; the cone remains relatively unchanged). The viewing cone only changes from 34º to 30º going from white to grey screens.

Da-Lite lists their viewing cones as 60º and 40º for HP and HCHP, respectively.

I'm not sure how these numbers work out, though, since Da-Lite lists their half-gain (2.4-->1.2) happening at 20º for HCHP, while Draper lists their half-gain as 15º (2.7-->1.2, yeah slightly less than half-gain) for their Contrast Radiant. Yet, when I go far off-angle, the Draper Contrast Radiant has at least as much, if not more, gain than the HCHP.

Hence, I went with my own measurements, and am swapping out my Da-Lite HCHP for a Draper Contrast Radiant (fixed frame, permanently tensioned: Onyx line). Guess I'll be the guinea pig here!

Since I did the experiment of brightness vs. viewing angle for a patch of Draper Contrast Radiant over the HCHP screen, after I get the Draper screen, I'll do the reverse experiment: a patch of HCHP on top of the Draper screen

To once again summarize the results of my Draper Contrast Radiant patch over the HCHP screen experiment, if I calculate the fall-off of each screen relative to the original 5º angle brightness, and normalize the numbers such that the 5º viewing angle shot of the HCHP has a gain of 2.2 (which is what I consistently measure for my setup when comparing the HCHP vs. a matte white screen), then these are the gain curves I get for HCHP & Draper Contrast Radiant:



As you can see, in my setup, the Draper Contrast Radiant at least holds up as well to viewing angle as the HCHP; in fact, it holds up better. Finally, once again, I don't know if this is because my HCHP screen is dirty or something...

Actually, rather than speculate, I'll just redo the experiment tonight with a patch of HCHP sample to see if the HCHP patch holds up better than my 110" HCHP screen.

Could you be more specific? Yes the Draper CR has slightly higher gain (or the same, depending on experimental error, which I didn't quantitate, b/c really I actually do have better things to do with my time ) than the Da-Lite HCHP at all angles. Why would this defy physics?

Look at my latest post. The viewing cone barely changes when you go from Draper Contrast Radiant (HCHP equivalent) to Radiant (HP equivalent). It's possible that Draper didn't bother putting a higher gain coating on their grey screen than their white (which'd also explain its lower gain relative to the white retroreflective equivalent). Hence it may hold up relatively well with off-axis viewing angles.

At least as well as the HCHP. That's all I'm saying.

Btw I saved $102 by going with the Draper over the Da-Lite (same fixed frame version). So, it's slightly cheaper, if anything.

I redid a test tonight to quantitate gains of HP, HCHP, Draper Contrast Radiant, & Draper Radiant using the patches only (instead of my full HCHP 110" screen). Will quantitate all that and post back tomorrow.

As it turns out, preliminarily just looking at the photos, my 110" HCHP screen has lower gain than the HCHP sample patch Da-Lite sent me. Most likely due to my NEW screen being really dirty (well, that's one explanation anyway)...

Hence re-quantitation of my gain curves is required using just the sample patches. More tomorrow.

Actually you're correct as you explained in your previous post - it's the difference in grayness.

Too bad the CR isn't what I thought - an even more directional retroreflective screen.

My situation is exactly what they describe as benefiting from that, a long narrow room with small viewing angles and poor light control.

Not sure I understand. CR & HCHP sound perfect for your room. Same for me.

If you want a less directional retroreflective screen, get the Draper Radiant or the HP.

The only real problem here is QC of the screens... seems both HCHP & HP have texture & may arrive very dirty (like I said, mine is so dirty has to have significantly less gain than all HCHP sample patches I received from Da-Lite).

What remains to be seen is if Draper's full surfaces are any better.

I'll post some more quantitative graphs from last night's test later today (hopefully). They're very interesting.

For the sake of not spreading misinformation: a close inspection of the underlying weave/texture of the Draper Contrast Radiant sample & the HCHP sample indicate that they're exactly the same material.

Sorry, previously I'd said they were different; must've been the lighting.

I went back & corrected all my posts.

Sorry about that.

Of course, this worries me now. Perhaps the Draper Contrast Radiant & HCHP are sourced from the same manufacturer... which wouldn't bode well.
Edited by sarangiman - 1/11/13 at 12:19pm