Originally Posted by RedBull1985
Been following ur efforts for the last couple of months and a big fan of urs. Am a first time PJ owner, just got my Epson 3020 last week. Was intending to setup a Spandex screen as I thought it would be having ALMOST the picture quality of a branded, solid screen. Now, the above conclusive comment of urs have confused me. In ur experience, how well would a Spandex screen stack up against a solid screen of comparable price range ? Like say,a 50 percent reduction in outright quality?
wow. A fan eh? Guess next thing I'll be needing is a Club.(...for someone to smack me over the Head with if I get too arrogant, no doubt.
) Really though, thanks for the compliment as it is intended.
Let me try to make my previous comments more clear, and then also add some even more definitive comments as to comparable quality.
1. Any Reflective cloth that is also porous enough to let sound pass through unobstructed (ie: inaudible changes ) is to be considered "Acoustically Transparent".
2. Those who wish to have speakers placed / concealed behind a Screen "REQUIRE
" a Screen that is made specifically to be "Acoustically Transparent".
3. Due to their needed "Aural Porosity", "Acoustically Transparent". Screens have less reflective surface to receive / reflect projected light, and all light not reflected is passed through.
4. Directly related to no.#3....... "Acoustically Transparent". Screens habitually have gain levels of under 1.0.
5. Mfg. "Acoustically Transparent". Screens that have positive gain (...the most expensive kind...) often exhibit weave /perforation characteristics showing the difference between the higher gain solid surface and the open areas between the weave /perforations. During bright panning sequences, this often is visible on the screen as something known as "Morie".
6. The less "open" a surface is, the more area of reflectivity it possess. But usually this means the surface is decidedly "Less
7. Spandex has a tighter weave / (more but smaller openings) than any Mfg. "Acoustically Transparent". Screen, however the nature of Spandex's composition makes it a much LESS dense a Material than any Mfg "Acoustically Transparent". material.
8. No.#7 allows Spandex to due the job of virtually any Mfg "Acoustically Transparent". material regardless of expense, and do so at / for less than 1/3 the material cost.
9. Spandex however is not a solid reflective surface, so it too must suffer a varying degree of light lost through pass-through absorption.
10. It is accepted practice to back Spandex (...and Mfg. "Acoustically Transparent" Screens as well...) with either light or dark "Acoustically Transparent" Cloth to hide the Speaker's outline from absorbed Light.
11. If a lighter Cloth is used for backing the less gain is lost due to reclamation and reflection back through the openings of the Weave / Perforations
12. If a darker Cloth is used for backing, the the openings that allow light to pass through can also direct reflected (...but attenuated...) light to return to add contrast.
When added contrast is the goal with a "Acoustically Transparent". Screen, it is usually effected by attenuation the PJ Lamp's output. between the light lost through surface absorption, and the reduction of lumen output, many "Acoustically Transparent" Screen applications suffer from a less than stellar image (...brightness-wise...) As a Rule, in the past most "Acoustically Transparent" Screen owners were also CRT owners, to whom Black Levels were never an issue. Nowadays, it's more probable that "Acoustically Transparent" Screen owners will have a preponderance of Lumen output, but less inherently deep Black levels. (...that's changing fast though...)
So now to directly address RedBull1985's
question and concern about the potential Image Quality differences between a Spandex Screen and a Solid Screen. Since "Acoustic Transparency" is not an issue when comparing a Solid Screen surface to a Spandex surface, that issue is wholly moot.
If a End User needs to have a Lightweight, removable, hang-able Screen, Spandex has seemed to come around to fill a niche long held by the venerable Blackout Cloth Screen application. Blackout Cloth itself was / is a solid Cloth, but seldom came with a Gain factor of more than 1.0....and usually had only 0.85 gain. In truth, it was / is the necessity of constructing a considerably stout Frame to accommodate the tension needed to keep the heavy Blackout Cloth taunt, flat and wrinkle free that presented the most daunting challenge for any DIY'er. Both effort and cost wise.
But of course, a material like Blackout Cloth can be used as a very effective "Canvass' on which to apply virtually any DIY Screen paint applications, making it the virtual equivalent of a "Solid Screen"
Any Solid surface will have a more effective reflection index than a open weave cloth surface of the same color. Spandex's weave is very tight, but the threads themselves are very small, and when stretched, the openings between those Threads increase in size, allowing more light to pass through. Spandex can never have the degree of effective reflective surface area of a solid surface.
However, that same density and compactness of Spandex's weave becomes more than sufficient to reflect "ENOUGH"
projected light if enough Lumen output is available. If said Spandex is made of a Gray / Silver color, then an added perceived increase in Contrast can be had. If the projector being used already possesses exemplary Contrast, Spandex will not detract from that potential, but rather augment it if such contrast is also accompanied with sufficient Lumen output.
Now then....how much better can a Solid Screen be than a spandex screen? And by what percentage?
Please keep in mind that my following comments are based on Conjecture, but conjecture that comes from experience. YMMVW.
A matte Silver Spandex Screen, (of any reasonable size) stretched properly and backed with White Spandex...and hit with a Epson 6010 / 6020 calibrated to that color surface, would under 95% of the population's eye, present a fabulous image that could not be picked apart except by that lousy 5%.
A Solid Screen, painted that same color / shade of matte Gray determined to be of the same gain would fare no better, nor worse...excepting when viewed from under 12" distance, whereas one could see the Fabric's weave, but fail to see any texture on a well sprayed Solid surface.
With RedBull 1985's
8200 in play, both the above statements retain complete validity as well.
The difference would start to become more noticeable if a Gray / Silver Screen paint applied onto a solid surface had significantly more gain (1.1 to 1.4 gain). The differences would also be noted of the Projector's Lumen output fell significantly, with that being more so the case with the Spandex Screen. Both the above pertain to Foot Lambert of Reflected Brightness off the surface of the Screen.
And I'll state this as irrevocable fact.
DIY Screen app was a full 50% less effective than another, it would be a cold day on the surface of Betelgeuse that I would even bother to consider it worthy of this DIY Forum's time or space. Fortunately (...with the exception of those projecting onto their Tan / Mauve / Blue Walls
) there is almost no one who posts on here who is willing to even consider accepting such a low standard of performance. Expectations run high in DIY Screen making....and I and others such as I try our darnedest to keep those expectations....and results as lofty as possible.
So if you see any application listed on this Forum as being "Under discussion" or being attempted more than once, you can be sure it's at least 85% as effective as the best of 'em. Within the scope of that 15% difference lies a lot of personal choice and need. The Forum exists to help others determine exactly what choice is needed, or in lieu of that, suggest the next best possible choice...and so on.
But rest assured, if the quality potential of what someone says they "must" do falls too far, they'll know.....'cause we'll tell 'em so!