Acoustic Transparency of Spandex - The Truth - Page 10 - AVS Forum
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post #271 of 286 Old 08-02-2014, 02:56 PM
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Originally Posted by ryanoletzke View Post
Oh... and for 120" wide by 68" tall screen made of milliskin... how many yards is that? And do they sell milliskin in wider strips than 58"/60" ?

Thanks again!
You would need 4 yards.

You would be "stretching it"....literally speaking....trying to get a 72"-74" stretch out of a 58" wide piece of Spandex.
The 135: screen shown above required a 65" "face" after stretching, and I recall that I was worried my Staples would pull out or the Fabric's weave would distort. I really had to tug to make it work....for Spandex at least....and when really stretching Spandex that means you'll have to be all the more careful and precise making sure it is stretched evenly in all directions.

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post #272 of 286 Old 08-02-2014, 03:12 PM
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Maybe I am reading it wrong
Here is a pic of it. I am thinking 120" wide, so 138" diagonal...

Am I missing it?
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post #273 of 286 Old 08-02-2014, 03:19 PM
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Originally Posted by ryanoletzke View Post
Maybe I am reading it wrong
Here is a pic of it. I am thinking 120" wide, so 138" diagonal...

Am I missing it?
You have the Gain set a 1.0, and that's not what you can expect. It would be much closer to 0.85 to 0.8

Makes all the difference.
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post #274 of 286 Old 08-02-2014, 03:52 PM
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Originally Posted by MississippiMan View Post
You have the Gain set a 1.0, and that's not what you can expect. It would be much closer to 0.85 to 0.8

Makes all the difference.
Ah... OK. What fL amount do I want? If I go white/white and if I go silver/white...
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post #275 of 286 Old 08-02-2014, 03:54 PM
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Originally Posted by ryanoletzke View Post
Ah... OK. What fL amount do I want? If I go white/white and if I go silver/white...
Would it help if I reduce the screen size to 115" wide? that would be 65" tall I think. Better for stretch of milliskin and maybe better for fL (because I could get away with putting it closer to screen)
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post #276 of 286 Old 08-02-2014, 06:06 PM
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Originally Posted by ryanoletzke View Post
Would it help if I reduce the screen size to 115" wide? that would be 65" tall I think. Better for stretch of milliskin and maybe better for fL (because I could get away with putting it closer to screen)
Absolutely. Look at my examples. Those were from a Panny 8000u at 16' on a White over Silver.

White on White will not work to improve Black levels any more than the basic reduction in gain allows. The Silver underlay will do far more....take my word for it this time.

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post #277 of 286 Old 08-02-2014, 07:38 PM
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Quote:
Originally Posted by MississippiMan View Post
Absolutely. Look at my examples. Those were from a Panny 8000u at 16' on a White over Silver.

White on White will not work to improve Black levels any more than the basic reduction in gain allows. The Silver underlay will do far more....take my word for it this time.

It's all gud, Bro.
I'm taking your word for it

I'm gonna do 110" wide by 62" tall (126 diagonal). Gonna go white milliskin over silver. This way the stretch of 58" milliskin isn't too hard. I don't "need" 120" wide, just knew it was the biggest I could go in my new room.

And gonna place the projector at 12'4". Predicting a screen gain of 0.7.

ProjectorCentral says fL will be at 15.

Thanks MM - I'm looking forward to "interstellar" blacks and a great picture with AT screen
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post #278 of 286 Old 08-03-2014, 10:31 AM
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Quote:
Originally Posted by ryanoletzke View Post
Newbie here... Making home theater in new house, looking for any advice/expertise on DIY screen.

Here is the current plan and info:

Room: 16' deep by 19' wide, 9 foot ceilings. No windows.

Projector: EPSON 8350, throwing from 14'6" (current thoughts, have 15' as max throw potential)

Screen: Planning to make DIY style: 120" wide, AT screen, 16:9 screen, from Milliskin (took me a while to read this whole thread :-))

Speakers: Left and Right BIC FH-6T, Center BIC FH6 LCR, Sub JBL es250P, haven't bought surrounds yet.


According to projectorcentral.com I can throw from 14'6" to a 120" wide 1.0 gain screen and have a brightness of 15fL.

Do I want more brightness? Should I do white over white milliskin? Any thoughts will be helpful as I plan to build the screen in the next week or two...

Thanks!
I would go white over white (I think your Epson is going to give the blackness even with higher gain). I believe I would buy 6 yards total (3 for each layer) just to be sure. You might get away with 2 yards per layer but I wouldn't risk it. As far as throw distances and fl, I have no idea. I would try a white bedsheet in the meantime and see what you think.
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post #279 of 286 Old 08-03-2014, 11:59 AM
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I would go white over white (I think your Epson is going to give the blackness even with higher gain).

Besides the fact that the Poster referenced to has already stated his intentions, I must disagree....even though I have installed many 8350s (26+) and was among the first to do so.

The brightness of the 8350 will work against the stated contrast specs on a purely white surface. It's 50K:1 rating is based upon the use of a optimally calibrated Cinema Mode, with the Auto Lens Aperture feature engaged and the lamp output set on Low Lamp. That means if the Normal Lamp Mode is used on a white surface, contrast will take a hit. And with a Spandex Screen, Normal Lamp Mode is almost always employed.

Conversely, if one has the Lumen output at hand, and the screen size / gain specs do not work against them, then the use of a Gray surface can result insignificantly improved black levels. And in this instance, since the Gray that is imparted, and the resulting attenuation comes not from the the Screen's 1st surface level but from the underlying material, the topmost white surface is allowed to retain and return a higher degree of white and color dynamics than a Gray would otherwise.

With advanced Gray painted surfaces, the same is accomplished using reflectivity enhanced mixtures. With Spandex, it's all about what the forward surface does, and how the rear surface both stops a greater amount of light from getting lost out the rear, while also deepening the shades of any light that is being reflected back through the top layer.

This is borne out additionally by the fact that some actually advocate using Black Spandex as a rear layer, which in turn both further attenuates light (ie: loss of more gain...) and deepens Black levels all the more. And they swear by the end results they get. I personally do not feel the additional loss of gain is worth the gains in Black Levels, but the again, if one was using a 3000 Lumen PJ with 10K:1 contrast, that would alter my thinking accordinly.

Sooooo.....any PJ that has adequate lumen output and yet "only" sports a contrast spec of 50K:1 can be better served by using a high contrast surface. And any multi-layer surface that provides an initial white layer will do all the more effective contrast enhancement without the Whites taking a significant hit.

In some respects, that means some degree of actual increase in "off the screen" contrast is happening....the Holy Grail of any such screen, and the basis of many claims made by Mfg Screens. Albeit few are valid.

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I believe I would buy 6 yards total (3 for each layer) just to be sure. You might get away with 2 yards per layer but I wouldn't risk it. As far as throw distances and fl, I have no idea. I would try a white bedsheet in the meantime and see what you think.
3 yards ea. is correct, and hopefully they were ordered to come rolled....not folded. Some have had issues with stretching out wrinkles.

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post #280 of 286 Old 08-03-2014, 02:12 PM
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Well... I ordered 4 yards of silver and 4 yards of matte white milliskin spandex last night.

I did just email them to request it to be sent to me on a roll. (fingers crossed) I certainly don't want creases I can't get out.

I have been reading that 16 fL is kinda the "mark to hit" for on screen brightness. I am projecting to be at 15 fL with my current set up. I guess if it doesn't look bright enough I'll just have to order more white.

Just to be clear, when you wrap the frame can you do both fabrics at once? Or should they be stapled in separate?
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post #281 of 286 Old 08-04-2014, 06:55 AM
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Quote:
Originally Posted by ryanoletzke View Post
Well... I ordered 4 yards of silver and 4 yards of matte white milliskin spandex last night.

I did just email them to request it to be sent to me on a roll. (fingers crossed) I certainly don't want creases I can't get out.

I have been reading that 16 fL is kinda the "mark to hit" for on screen brightness. I am projecting to be at 15 fL with my current set up. I guess if it doesn't look bright enough I'll just have to order more white.

Just to be clear, when you wrap the frame can you do both fabrics at once? Or should they be stapled in separate?
I believe you can strech them together. Somewhere (I have not found it yet) there is a thread explaining some technique to put it in a slot. If you find it please PM me with the link to it!

I plan on doing this very thing soon so I want to do it right.
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post #282 of 286 Old 08-04-2014, 07:25 AM
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Quote:
Originally Posted by ryanoletzke View Post
Well... I ordered 4 yards of silver and 4 yards of matte white milliskin spandex last night.

I did just email them to request it to be sent to me on a roll. (fingers crossed) I certainly don't want creases I can't get out.
You have to call them and arrange for the "Rolled" shipment because they charge a nominal amount more for that service. Also, it's problematical that a Email will get the request transferred to Order/Processing/Shipment in time. Why chace it. A Call with your Ordcer number will assure you of getting some unwrinkled material....Do it soon!


Quote:
Or should they be stapled in separate?
Separately.

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post #283 of 286 Old 08-12-2014, 07:16 PM
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Originally Posted by MississippiMan View Post
You have to call them and arrange for the "Rolled" shipment because they charge a nominal amount more for that service. Also, it's problematical that a Email will get the request transferred to Order/Processing/Shipment in time. Why chace it. A Call with your Ordcer number will assure you of getting some unwrinkled material....Do it soon!


Separately.
So... Spandex arrived. Is a little wrinked - tried to get it on roll - was too late

So - any advice on how to get wrinkles out??
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post #284 of 286 Old 08-13-2014, 03:25 AM
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Originally Posted by ryanoletzke View Post
So... Spandex arrived. Is a little wrinked - tried to get it on roll - was too late

So - any advice on how to get wrinkles out??
If they are just light wrinkles and not "Creases" then adequate stretching should remove them.

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post #285 of 286 Old Yesterday, 09:26 AM
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Excellent data here. I hadn't even been aware of using a spandex type material in lieu of the other options. I admit, I focused solely on the test results and some discussion here and there about the results, so I may have missed this... Was the Seymour UF tested? Before reading this thread, I was looking primarily at the Seymour XD or UF. The XD material seems like a great performer in terms of audio, but the varying concerns over moire are enough to give me pause. The UF literature implies less issues with moire but a loss in audio fidelity (perforation sizes alone lend themselves to these conclusions). After reading this thread, I'm obviously leaning toward the DIY material but am still curious to know if a direct comparison has been performed with the UF material, if nothing else than for completeness in comparisons on my end.

Edit: Removed remainder of post asking for help (because I hate when people go OT in my threads, so I don't want to do it to the OP here).

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post #286 of 286 Old Today, 07:28 AM
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If you desire exceptional quality in the Audio dept, then compromising to get more reflectivity by using a material with more solid surface area is not a viable answer.

If a Mfg material that supposedly has less reflectivity but better acoustic characteristics, yet sit falls short of what a DIY material can offer on both fronts, where then is the question as far as what would be better?.

Simply stated, those who usually need / desire acoustic screens, by their nature have dedicated theaters with enough light control that any loss of gain is easily enough offset.

Spandex excels at acoustics, usually keeps within a 0.8 - 0.7 range of gain, and costs much less than the Mfg materials. Also, and other "substitutes: such as Phifer Sheerweave fall to the wayside as far as performance in comparison.

All in all, if your a DIY'er with a desire to make something that works great, and does so on a budget, Spandex screen apps are a extremely viable choice.

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