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Acoustic Transparency of Spandex - The Truth - Page 8

post #211 of 251
Quote:
Originally Posted by MississippiMan View Post

you have absolutely no conception how far ranging my knowledge and involvement in Front Projection is.

Thank you. I think this pretty much sums it up.
post #212 of 251
Thread Starter 
I don't mind some off topic chit chat. But lets try and keep it civil and cool. I tested a mfg screen material, so naturally it'll be talked about. Let that happen.

Interesting the Enlightor 4k is being compared to the XD material. I just looked at their web info. They show comparison frequency responses. They use smoothing (12db/oct) instead of gating and their scale is 10db per increment. That's way to tall of scale for that kind of comparison. Careful when reading that chart, ther's well over 3db of attenuation. Which is still acceptable IMO if it's actually as consistently broad band as they show. They also show the impulse response and ETC, but no comparison. The impulse reponse appears useless, just a bunch of fuzz. Not sure that's even correct. The ETC looks correct though, but does show some jaggies. In the end, what I'm trying to say is, it's not a direct or fair comparison, but I think that spandex would meet or excede the AT quality of the Enlightor 4k based on their info. I'd love to play with the measurement files myself. Overall though, probably a fantastic product. So how much does it cost?

RTK, if you'd like one other "review" of the XD versus spandex. You may have already read my thoughts, but I couldn't deal with the weave at my 9 or 10' viewing distance. The XD had a lot more gain, but like Brian I found all the higher gain materials I've viewed on my screen gave up blacks. It simply wasn't worth the loss in blacks. But that part is subjective. I also feel inclind to note that my experience is based on a close viewing distance, a 92" screen, in a non-light controlled room (dark, but light coloured walls), on a high lumen PJ (Viewsonic PRO8200). My PJ can probably use the contrast help of the grey material. The XD and white materials just washed out, even with the lights off.

Good luck with your hunt for a nice screen. No doubt the mfg materials make for nice screens. It's a matter of whether or not you're willing to pay for the product. I'm cheap. But even if cost was not a concern for me, to be honest I would not feel like I'm missing out. I had no idea how much XD cost when I made my comparison. I would have guessed it's a $100 for typical 100" screen. When I heard it was double that, it was a closed case IMO. Still, even at the price, you get a good product.
post #213 of 251
Thanks Tuxedocivic. I've received AT samples from most of the major vendors and I'm awaiting my white and silver milliskin. I have an Elite 100" frame which I plan on converting to AT. Like most people our room has its challenges for both speaker placement and screen material to strike a balance between what sounds and looks best. I appreciate your comments (as well as others) regarding the visibility of XD's weave, which is definitely a concern. While our seating distance is ~12 feet, I suspect it might still be seen, which is what makes milliskin appealing.
post #214 of 251
I am personally 12 feet from a 126" XD screen and have no issues seeing the weave, even on very bright scenes.
post #215 of 251
Thread Starter 
I think you mean you can't see the weave? Almost sounds like seeing the weave is really easy, you can see it without issue, haha.

I'm not convinced screen size has anything to do with it though. Maybe smaller screens make it more obvious in fact. Seating distance has got to be the biggest contributer. But for screen size, the weave size stays constant. So for a large screen where the image is more massive, the weave is dwarfed. But on my small screen, the details are impacted by the relatively large weave size. Totally guessing here.
post #216 of 251
Haha, yes, I should have worded that a little better. I am unable to see any weave from my seating position. Lol oops
post #217 of 251
Tux,
Could it be that what you are seeing on XD is not the weave but moire effect? Can you check if tilting the sample changes anything?
post #218 of 251
Thread Starter 
I could see it best on a bright patch of sky or something homogenous. So I don't think it was moire, unless I don't understand that term correctly. I'll try again tilted. I tried the black backer but could still see it.

I'm fortunate to have insane vision. I can see a speck of dust across a room. 5 minutes ago I walked into my office and saw a tiny little piece of dust on top of my speaker from 10' away. A white piece of dust on natural maple, not even white on black or something obvious. Not trying to brag, just saying that my gifted sight probably has something to do with it. When I sit on my couch and look at the XD, I see the actual screen material as if holding it in my hands, just further away.
post #219 of 251
Tuxedocivic - how close was the black cloth to the XD (is it a sample)? I found with my woven samples when I tested the black behind (which was very close) seemed to make the weave more obvious.
post #220 of 251
Thread Starter 
It was right behind it, but I can't recall if it was better or worse. I wanna say the same.
post #221 of 251
I thought the same, that screen size doesn't change the size of the weave. But upon further reflection (pun!) I realized what you guys are getting at with the moire discussion: it's not just seeing the weave. It's the interaction of the weave with the pixel grid. Bigger screen: more zoom to make bigger pixels. The Weave's moire effects may become more or less pronounced as one varies seating distance, zoom, the projector (different pixel fill ratios), fabric tilt, etc.
post #222 of 251
No visible weave = no Morie effect, irregardless of zoom settings and / or Pixel size.
post #223 of 251
Thread Starter 
That's a good point Eyeleron. When it comes to optics, I'm pretty sure you guys have a better handle on things. Why I have in interest in audio more than video, I don't know redface.gif Probably cause I love music. I have golden eyes, but no golden ears here. biggrin.gif
post #224 of 251
Yup...if under no conditions one sees the weave, then no moire. If there's visible weave under the room lights, there may or may not be moire when projecting. Or the moire could change when changing screen size later.
post #225 of 251
I was just finished typing the below when I got notification of the post above...so this is just more of the same.

If any projection surface, with emphasis on cloth...and has so smooth a surface as to the fabric weave being indiscernible from 4' away, then any image, be it from a SXRD / Smooth Screen / CRT, or DLP/LCD @ 1080p, then Morie will never be a problem at any Zoom / screen size. Using a surface of such smoothness, the scale of the weave is almost always going to be smaller than the Pixel size, ( @ 82" diagonal + )and unless someone drastically overstretched Spandex, (or used 2-Way stretch instead of 4-way...) there is no way the openings in Spandex would ever remotely approach the size those of most any...if not all Mfg. AT Materials.

And it's the size of the openings, be they weave or perforation in approach, that creates the issues. AT transparency whenever a solid density material is used / made is wholly dependent on balancing size of openings against reflective surface. The Perforated Screens always have an advantage reflectivity wise, but can suffer badly from Morie because the "Black Holes" create a wider Grid to accentuate those nasty Pixel grids. As a image moves across such a Grid, the changes in light reflection also gets altered by the variable reflectivity of the screen. In worse cases, some content can create "undulating waves".

Woven Cloth style AT screens have done,and do fair better, but once again, those that have a more open weave to focus on any real degree of Transparency also suffer the most from potential Morie issues. The Mfg Screens with the most gain, owing to a very reflective but Flexible Substrate or Threaded Fibers, are the most affected of all. Small wonder that most all the earliest AT screen uses involved CRT owners with hidden Front Sound Stages in dedicated Theaters. They tended to pay whatever it took to achieve the level of performance they desired, so in that rarefied domain, a "Status Quo" price-wise developed. And that was essentially, whatever that Market could bear.

I myself gave up on depending on getting it right "{every time" using AT Screens....back in 2001-2002. Of course the pickings were slim, and horrendously expensive, so what where was the reason to love? Also, the PJs I was restrained to use were not CRTs or Early LyCos. And as many know well enough, I had to come to realize that most the Mfg Fixed & Retractable offerings were no better, performance to expenditure-wise. Those that were....well they only cost 1/4 as much as the projector...which doesn't sound too bad until one considers that the good PJs back in 2001 cost $25K

My efforts went a different direction. wink.gif

Perhaps somewhere, waiting to be discovered (...or created...) is a material that has a smooth surface of at least a true Unity gain, but also a degree of Audio Transparency that can match the best examples of open weave / large perforated AT screens.

And costs like Blackout Cloth....or less.

I said this a while back...and no one picked up on it....but if I could have Spandex that could offer the gain & contrast advantages of a painted surface....my Spraying days would be over.

I feel we are awful damn close "DIY-wise" using 4-way stretch Spandex. . But Morie issues? Nowhere have I read of that being the case with Spandex that is properly stretched.
post #226 of 251

I believe the last few posts reporting moiré are of the XD fabric, not Milliskin Spandex.


Edited by Eyleron - 5/29/13 at 7:23pm
post #227 of 251
Quote:
Originally Posted by Eyleron View Post

I believe the last few posts reporting moire are of the XD fabric, not Milliskin Spandex.

Well I know.....so that makes the knowledge of Spandex suitability in that regard just as valuable as it's acoustic attributes. Desirable attributes are cumulative, and according to the old "Ben Franklin" method of making a list of Pros & Cons, and going with anything that has more Pros than Cons, Spandex is a clear and easy decision for many to embrace. Not all / everyone...but many, most of whom are among those who could really use a viable alternative.

There really hasn't been / isn't much rush to proclaim such. I dunno...perhaps others don't want to admit, or support such out of hand, even when things only get better....not worse.


And really...what could be more off topic and inappropriate than narrowing down the discussion to simply what a Mfg Screen cloth can / connot do...without making a comparison of how a DIY alternative stacks up against such?


I personally have always encouraged action at DIY price points. Much gets concretely "proven" via extensive end user experience. If every DIY "idea" that has found acceptance by "get'tin Dun" had to wait to be tested, vetted, and officially indorsed by those who are more apt to deny it's value, we'd all be using Bed Sheets and White / Gray Latex Paint.....and that's about all.. biggrin.gif
post #228 of 251
I'm invested in the Milliskin such that I recommended for my boss' theater AT screen. He initially doubted the efficacy of silver over white for ambient light situations, but some trial drapings and projecting blew him away: white surface was too washed out; he needed the contrast.

I don't think we should be surprised that people will debate DIY solutions. We're taught to be leery of free or cheap. On AVS Forum we argue and debate everything. And only last November Moleskin was the fabric to use. This is all new stuff.

The acoustic testing helps a lot, especially for folks who are passionate about audio. Personally I built my speakers from a kit of Tux's design and my boss is using Tux's in-wall version of those speakers, so his endorsement of some fabric and not others, their layering and placement affecting the acoustics...provided surety and confidence.
post #229 of 251
Thread Starter 
Quote:
Originally Posted by MississippiMan View Post

the good PJs back in 2001 cost $25K


Ouch, bringing back bad memories. We bought our first in 2002 iirc and it was used for $4000. My $800 viewsonic blows it away. Mind you, the blacks on that thing were superb. It was a CRT or what ever, with the RGB canons. You know. Excellent blacks from what I remember. My Dad DIY'ed the screen back then too! I think it was some kind of MDF that he had his painter spray. He was a contractor so just had the MDF and had the painter around anyways. Blew us away at the time, but for $4k I'd be laughing now 'a days.
post #230 of 251
Thread Starter 
Quote:
Originally Posted by Eyleron View Post

He initially doubted the efficacy of silver over white for ambient light situations, but some trial drapings and projecting blew him away: white surface was too washed out; he needed the contrast.

I know what you mean. I've had a few friends ask why it's grey. I explain to them and they kind of blank stare at me. I tell them it's not quite as bright though and then they say "oh ya well it's gotta be bright". Then I drap a few samples over and they quickly agree with me biggrin.gif
Quote:
Originally Posted by Eyleron View Post


The acoustic testing helps a lot, especially for folks who are passionate about audio. Personally I built my speakers from a kit of Tux's design and my boss is using Tux's in-wall version of those speakers, so his endorsement of some fabric and not others, their layering and placement affecting the acoustics...provided surety and confidence.

Glad I can offer surety and confidence smile.gif And I'm looking forward to hearing how the in-wall install goes.
post #231 of 251
Quote:
Originally Posted by tuxedocivic View Post


Glad I can offer surety and confidence smile.gif

It's your strong suit! cool.gif

Despite what has been said, I myself am not against effective evaluation and testing, when done with a open mindedness and through, unbiased approach. And "unbiased" certainly doesn't include posting degrading personal slights or wholly dismissive commentary, as such only serves to destroy the objectiveness of any published Test results. Everything instead just becomes so much self-serving tripe, especially if such becomes a continual pursuit.

And from experience I know all too well how easily some get caught up parroting the expressed views of others. It's an "Internet" kinda thing that some find it easier to be contrary and side with those who express themselves as such. More exciting? No....it really involves a character flaw. For my part, some of my previous posts were just my own attempts to rebut such efforts, and put another perspective out there. I'm only sad, and apologetic if at times it all had to taint what was / is your own effusive efforts.

In all those "negative" regards your efforts have been exemplary to the opposite end of the scale...and such an effort (...and the Thread...) deserves courteous responses.

Above all else, it's the number of those who will benefit from the posting of definitive info, be it subjective or conclusive, that is what it's all about, not trying to force a personal opinion / feeling on others like it was an agenda.
post #232 of 251
Quote:
Originally Posted by tuxedocivic View Post

Hey Fred,

The procedure is not difference than that laid out in post 1. I hope to soon organize this thread a little bit to get all the data all together for easier reading. Right now it's spread through the thread. The only difference this time, is ti's sunny out so I measure outdoors. This allows me to get my gate time way out to 7ms. Now, in case that sounds like a big deal, it's now, we're only interested in >500hz essentially, so I could have done this indoors but I was already outside for a diysoundgroup speaker project. The bare speaker response did NOT change.

Ok, here's an apples to apples look at XD vs 2 layers of milliskin. Here's a difference plot. The closer to 0db the less "distorted" the product made the speaker. You can see there's hardly any difference at all.



Here's a full scale difference.



Red is XD and green is 2 layers of miliskin. You can see they're both very close. And if you were to go with only 1 layer, well, it's clear the milliskin hardly touches the sound.

Could someone please provide me with links to the millskin used in the test above? Thanks!
post #233 of 251
Quote:
Originally Posted by tryrrthg View Post

Could someone please provide me with links to the millskin used in the test above? Thanks!

http://spandexworld.com/c3/catalog/browse/33
post #234 of 251
Anyone tried Miliskin white (top layer) over black (2nd layer backing)? Also, anyone tried the stretch velvet from spandex world?
post #235 of 251
Quote:
Originally Posted by WereWolf84 View Post

Anyone tried Miliskin white (top layer) over black (2nd layer backing)? Also, anyone tried the stretch velvet from spandex world?

Although Black backing has been used extensively with AT materials, it's primary purpose is to prevent adverse reflections coming off objects behind the screen. It is and has never been about preserving or improving the optical quality of the actual AT projection surface as far as what is reflected. Once light passes through, if it is not reclaimed or retained to some extent, it's lost....and there is / can be no disputing that.

The choice to use White / Gray / Silver Milliskin / Moleskin is based on potentially both premises. If AT is desired, then Milliskin is the choice. However, if retention of gain is needed to absolve one's self of undue attenuation of reflected light, allowing light to pass through and be absorbed by a Black backing (or no backing) isn't what can be construed as being beneficial.

If AT is NOT in the cards, then the use of a White Milliskin for ultra-High Contrast PJs works well. A Gray or Silver backing, one that lays flush against the back of the surface receiving the projected image, is just a cloth variation of using a White / Gray / Silver coating on a solid substrate. The latter has never been in dispute as being an advantage, with bot Mfg and DIY'ers availing themselves of such.

Yes, most Screen Mfg using White Vinyl as a screen surface apply a Black backing, but this is more for Contrast enhancement owning to the small degree of light that passes through all but the most opaque materials. In the same light, the use of Silver Metallic backing, Mylars, even Mirrored surfaces (DIY= Light Fusion / Mfg = Vutec UHG ) is considered both appropriate and often highly beneficial.

All to often, what one person "measures" is expected to be the only definitive source of consideration, End Users' own determinations notwithstanding. In the drive to use inexpensive and unconventional materials, a different approach to determining viability is needed. Those who strive to make tests and use examples with the sole intent of either pointing out the deficiencies of, or disproving the use of DIY materials altogether are not holding to the mandate and intentions of true DIY screen making as much as they are simply promoting the use of Mfg Screen materials. DIY needs not be absolutely perfect, nor out of hand conform or exceed the abilities of a similar Mfg offering. Usually, close is close enough, especially when a considerable difference in expense is involved and taken into consideration. That many such DIY efforts can and do exceed the attributes inherent in their Mfg counterparts only adds fuel to the "comparison fire". It is both a Boon & Bane that DIY Screen making has been taken to the extent it has, allowing for levels of performance that are often more than anyone can reasonably expect from such inexpensive applications. Nowadays, it can serve to put a Bulls Eye on such DIY efforts.

My own experience and observations have shown that White on White maintains gain to the point that almost no appreciable loss of gain below unity1.0 level occurs. If Moleskin is used, this applies all the more. Use of a light Gray or Silver is desirable if a improvement in "on Screen" Contrast / Blacks is needed / desired.
post #236 of 251
Quote:
Originally Posted by WereWolf84 View Post

Anyone tried Miliskin white (top layer) over black (2nd layer backing)? Also, anyone tried the stretch velvet from spandex world?

Hey Wolf,

I'm using white on black milliskin, but the layers are separated by an inch. This seems to work quite well.

Mike
post #237 of 251
Thanks Mike, any screenshots to show the picture quality?
Edited by WereWolf84 - 6/11/13 at 5:17am
post #238 of 251
Here is a quick shot before calibration taken with my iPhone:



The black horizontal bars are part of the photo from the screen shot...
post #239 of 251
Thread Starter 
That looks fantastic smile.gif
post #240 of 251
mhutchins,

Take a shot/s from a distance where you can zoom in, but "NOT" clip the edges of the screen. Shots like the one above allow the Camera to meter only on the center, and always show a more saturated image than what is present.

That is why most Screenshots are done in that manner....to make 'em look as good as possible. But it only amounts to being Eye Candy. As stated, if you stand back at least 3x the width of the screen, then using only Zoom, frame the screen with about 30% of the Camera's image fie4ld showing the wall behind, then a much more accurate depiction is presented. The Zooming attenuates the excessively bright reflection on the screen just enough to bring it closer to parity to the room light / lack thereof.

Some take multiple "bracketed" shots using auto grayscale / color / contrast correction features so they can cherry pick the best looking image, but that amounts to far too much "in Camera" processing. Accuracy in Screenies that purport to show performance is essential, lest they give ammunition to those who decry the validity of such.

I am certain that one thing that is happening is your 1" Black Backing is helping provide deeper contrast, at some degree of further loss of gain, but until Tux can take measurements using the White-over-Black method, and make comparison to White on White w/no backing, or White / Silve,r the Jury is out as far as a concise verdict.

Lastly, and in direct relation to the last statement above, what PJ are you using and at what throw is it placed? I remember back a ways your stating that your room had significant ambient light issues.....it would seem the Spandex solution wouldn't do much to alleviate those concerns, except for the fact that since your screen is only 110" (54" x 96") you do have some "brightness" advantage over the Folks doing 130"+ sizes, so the use of the Black backing doesn't affect you as far as light loss as much...there is that as well.

Below are 3 shots of a 135" White over Silver hit with a Panny 8000. No excessive zooming to fame the image in this shot....only a minimum.





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