110" DIY Spandex AT Screen - Page 6

smokarz,

By your own description of your room it's indicative that you must have realized room reflection issues ARE NOT overblown and there is a need to address them because your own Theater was / is made to mitigate such. If not, and the room's colors were never changed, then in reality you are not in a position to judge how "overblown" room reflection issues are because obviously, your room doesn't "reflect" you even ever had such issues. Ditto for Can lights set to the side and run at -75% dimmed. Used in such a manner, obviously they should not / would not / do not present a problem,

Why not turn those lights up to 100% and take us a few screenies of Underworld? Then do it again ay 75% dimmed. I promise you no one will criticize the effort or question the validity of the shots. Oh yeah....use a couple of Test Patterns too...of course. View and consier the results, then pause to reconsider you statement.

All that really needs to be said, and should have only been said is that rooms where at least some effort has been made to mitigate reflections, and where sensible placement / use of lighting is employed might very well accept the use of a white screen,,,,,with the condition that the PJ is fully capable of providing the level of Black rendition and contrast that is needed for one's personal satisfaction.

Your statement was essentially a blanket dismissal of an issue 90% of every other DIY'er needs to be made aware of.


tank01

The use of 6 Spots at 25' from the screen to illuminate the Pool Table is infinitely wise. I advocate spots to almost every person I address Theater design issues with, and in your situation the proper use shows how little effect they have when properly configured.


So.........both situations above allow for the use of a white screen "BECAUSE" they address common concerns and needs.....whether each circumstance's solution was intentionally done or just a happy coincidence, neither situation speaks out against the need for the right screen for a given situation.

tank01
The use of 6 Spots at 25' from the screen to illuminate the Pool Table is infinitely wise. I advocate spots to almost every person I address Theater design issues with, and in your situation the proper use shows how little effect they have when properly configured.
So.........both situations above allow for the use of a white screen "BECAUSE" they address common concerns and needs.....whether each circumstance's solution was intentionally done or just a happy coincidence, neither situation speaks out against the need for the right screen for a given situation.[/quote]

This setup was intentionally decorated, and the main concern was to darken up the environment , and to try and help out the projector as much as possible. The main concern was to have a nice decor while allowing the projector to perform anyway.

I wouldn't be recommending a white screen to anybody who is not willing to put in the time and effort to somber up environment and to make it work. But if you have done some of these requirements a white is amazing.

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Unless I am blind, I cannot find any post that explains the best way to stretch the dual spandex screen into the tracks. In the BOC threads, there is the "canvas stretch" where you make a diamond pattern and continue working your way from the center of each side to the edges while alternating sides. Are people doing the same with the spandex and spline in some way? I thought I had read somewhere where one fellow attached one whole long side then stretched it to the opposite long end. What was not answered is how the side-to-side was stretched.

Sorry if this has been answered but I just could not find it.

I have watched just a few non-calibrated movies on my 8350 projected onto a temporary black out cloth screen in living room mode and LOVE IT. Anyone else running an 8350 with spandex? If so, what spandex combo did you do and what color mode did you run? I have a light-controlled room (no exterior light at all) but have a white ceiling and white wall cabinet unit behind the screen.

Interesting question! I'm thinking the same and haven't found any suggestions how to best stretch the spandex. So i'm eager ears/eyes to people who have done this.
I was thinking of attaching one side first, but just as you point out, how do you deal with the side to side stretch after that?

is this moleskin silver the same as the one at spandexworld
http://www.fabricsworldusa.com/site/products_details.php?product_id=1488&cat_id=33

As I begun I realized this issue as well. Once you start you realize it's not that big of a deal really because the stretching isn't quite as much as you'd think to where you might end up with bunched up corners or weird angles or something. I basically attached one long side by lining it up so that the edge was straight and there was no need for cutting. As I got to the corner I began pulling it out towards the short edge too. This was sufficient to stretch both the long edge and then start stretching the material towards the short edge too so that when I started the short edge the material was already headed that direction... if that makes sense.

Hard to say since it doesn't say what surface it has, is it shiny, matte or rough? But the amount of spandex in it is the same ...

And it looks like the Matte Moleskin Silver is out of stock, once again , at Spandex World ...

Ha ha! I guess i'll be reading this several times before i get it

So did you start putting in the spline for the the first short edge at the corner or in the middle? And did you do both short edges before the opposite long edge? Sorry, just trying to "wrap" my brain around it.

Four edges and four separate pieces of spline. I didn't attempt to continue any of them around the corners. So four edges and four separate pieces of spline independent of each other. So I did long edge, long edge and then short edge and short edge.

Awesome, thanks!

Has the AT properties of spandex been measured before? It does seem strange that they've been used for so many months. And I agree on the measurements of brightness...knowing that lumens drop would've been nice.

I've measure. I plan to start a thread, but for now just look here.

http://www.diysoundgroup.com/forum/index.php?topic=127.msg1551#new

Second graph in reply #8. Note that an unsmoothed gated response using a calibrated mic.

Wow, awesome. So, two layers of Spandex, stretched to whatever extent you stretched it (maybe we should use the term Stretch Ratio. As in SR=1.2 for a 20% increase in area, or SRh=1.1 SRv=1.2 for stretching that's unequal in each axis?) filters the response like speaker grill cloth?

Thanks!

Good point. I stretched it probably 20% horizontally and 10% vertically. That's also a Joanne's white under a Fabricland grey. The Fabricland stuff seems heavier to me. Like it might block more sound than the Joanne's. I'll be doing more testing too. And a dedicated thread that presents the info better.

If anyone has a scrap of spandex world I can test that. I don't need much to do the test right. Just a scrap in an envelope.

I think it looks very close to a single layer of moleskin from spandexworld i measured against SHO-10




red - naked compression driver
blue - spanedex lightly stretched on a frame approx. 1" from the baffle
green - spandex tightly draped around the cabinet.

Edit: the response is gated and unsmoothed. Even though I tried to maintain position of the microphone and its disitance from the speaker for each measurement, there must be some discrepancies. I think that may explain why green curve has higher amplitude than the naked driver at some frequencies. But I think in general one can safely say that the more spanedex is stretched the less attenuated the FR is .
Edited by zheka - 12/23/12 at 2:18pm

I just stumbled onto this thread, and the whole idea of spandex as an AT screen. I LOVE IT! Cheap and offers up options for gray/white screen types. I would also like to thank Tux for measuring the effects the spandex has on the speakers when used as an AT screen. That made me a believer!!! Now it's time to start convincing the wife another HT remodel needs to happen.

No problem deewan. Keep your eyes peeled for a thread dedicated to the subject. And zheka also got similar results, sober have some consistency. I've also got some spandex world stuff coming. We'll be able to really see how good this stuff is soon.

I'm loving it. Previous was a different PJ, different setup, different house, etc. so not really able to compare. But it was a painted DIY. I really like this an being AT is really awesome. Helps that I'm absolutely in love with my in wall speakers. The best sound I've ever had. Eliminating the box and baffle issues helped a lot more than I thought possible.

Tough for me. Epson 8500, but I'd still want the better blacks with a gray/silver but when bulb starts to age I wouldn't want to lose too much brightness.

One tip for mounting the spandex: First loosely mount it to the frame and then look closely for imperfections in the fabric. My original top layer had stains on it from packing/shipping. My replacement top layer had a visible horizontal line in the fabric (looked like a dye issue) that was visible in bright scenes. Taking the fabric off and flipping it around so the other side faced out eliminated the issues.

Thanks for the pics,has that been re-calibrated since you went from the white painted to the white Spandex? Seems like a lot of light loss.
I was actually hoping for a better showing on the whites with the white on the front, instead of the silver that most folks are doing, as that was what I was planning.

Done the white>grey>mix>different mix> DaLite HP, and it's gonna be hard going back to a greyish screen.....seriously re-thinking this AT screen now, and I ordered the Moleskin Silver and White earlier today...... well at least it didn't cost me a fortune, I can rip it down in 5 minutes if I hate it, but the problem is I really wanted an AT screen in this new theater build I am getting ready for.....I guess I could build the screen wall with space in the back of it for speakers and subs, and if I hate the screen I can put my DaLite back up, but then I will have built the false wall for nothing but wasted space and subs...........maybe I can put a sleeping bag back there and a small fridge and toliet for when I'm arguing with the old lady..

Thanks

And that blows.......are the Seymours and others whiter than this fabric?