Will the Curved Screen Builders Please Stand Up! - AVS Forum
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post #1 of 12 Old 07-08-2012, 12:46 PM - Thread Starter
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So my old projector (Benq W5000) died and I ended up buying an Optoma HD3300. I love it, but in order for it to fit my fixed (read: borders glued to the wall) DIY screen, I had to move the projector closer to the screen. I am currently using an anamorphic research lens with the CA fix. What I am getting now is a much more noticeable pincushion distortion than before (I'm at around 1.8 throw ratio). Also, I realize that a curved screen will most likely not fix the softening at the edges, but perhaps it may make it a little bit better? At any rate, I'm also hoping to make a curved screen that is moveable, acoustically transparent and, if possible, uses a weave that is 4k projection friendly.

I have used Aussie Bob's spreadsheet, so I know the curvature that is needed. What I need help with is how in the world to build this thing. I have a buddy that is a welder but he is far too busy, so it looks like I'm stuck with using wood. Can anyone who has built a curved screen using fabric let me know how they went about doing it? I'm a visual learner, so any pics would be much appreciated. Oh, and if anyone knows of an AT fabric that I could purchase that is 4k friendly, that would be awesome. I had a bookmark for a company that sold DIY fabric, but I had to reformat my computer and my brain just doesn't remember stuff like it used to...

Thanks in advance for the advice/help.

PS. The thing that is weird is that my DIY screen is 2.37:1 and my Benq fit it perfectly, but now with my Optoma in order for the sides to fit in the screen I am getting black bars on the top and bottom. Seems that the anamorphic modes on these two projectors are definitely different.

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post #2 of 12 Old 07-08-2012, 02:23 PM
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I don't know the answers to your DIY screen material questions, but the reason you now have black bars is that you changed the throw ratio. Throw ratio also affects aspect ratio.

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post #3 of 12 Old 07-08-2012, 08:16 PM
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Here is a link to mine

http://www.avsforum.com/t/1258660/my-diy-curved-at-screen-with-masking


The way I did it was to find out the depth difference from the sides to the center using the aussie bob spreadsheet. I then bought lumber that was different in width and placed them as studs where the radius would hit those distances on the way to the center of the curve. Sides started with 2x6s then 2x4s then 2x3s, the backs of the 2xs are all on the same line creating the step in when looked at from top down. The center board I used a 2x4 but I had to inset it off of the line the rest of the boards were on in order to make it flush at the proper depth f the curve. Feel free to ask more questions about it, I hope the pics help but I forgot to take pics from beginning to end.

-Sean
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post #4 of 12 Old 07-08-2012, 09:33 PM - Thread Starter
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Sean! That looks fantastic, yet at the same time totally doable for the average DIYer like myself. I already have a long speaker base that I can build the screen on top of. I'm not totally sure as to how you placed your 2x4's for the curve, but I think what I'm gonna do is get two pieces of 2x10 and cut the curves and place the 2x4's perpendicular along that curve. I did find a good build thread from the Seymour AV site (this is the site I forgot), but yours definitely looks more stable. Question:

1. I was under the impression that the only viable way to tension the material is from the back of the screen to prevent any bunching up due to the curvature. How did you mount your screen material?

Looks great and I'm going to keep researching this. Anyone else care to throw in their build or thoughts?

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post #5 of 12 Old 07-09-2012, 04:13 PM
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Thanks for the compliments!

Ok, so the 2xs are not "flush" to the curve, they create the curve that a 1x4 follows. I have a 1x4 frame that is screwed to 90 degree angle brackets that are screwed into the 2x "studs". The studs create the curve as I figured this would be much easier than trying to jigsaw a perfect arc. Left to Right the studs go: One 2x6, One 2x4, One 2x3, One 2x4 in the center that is staggered back so that its actually like a 2x1 3/4 or something like that, then One 2x3, One 2x4, One 2x6. All of the studs, with the exception of the center start with their "backs" on the same line, this way they "step in" on the front and create a curve for the 1x4 frame to follow. My velvet wrapped border is a 1x8, it is also what the screen attaches to. The velvet frame attaches to the 1x4 frame via screws in the back going from the backside of the 1x4, through the 1x4, then partially through the 1x8 but not all the way through the 1x8 because you don't want screw tips poking through your velvet and sticking out the face of your screen's border. Since it is screwed to the 1x4, it adopts the same curve. My screen's material is the Seymour XD, I asked Chris to add grommets to the material pre-shipment, an option that costs more but worth the price IMO. My screen is attached to the velvet border using D-rings attached to O-rings, the O-rings go through the grommet holes and then hook onto picture frame hooks that I placed on the backside of the velvet border. The D-rings are larger than the grommet holes so they don't get pulled through. Since the screen is attached to the picture hooks that are attached to the velvet border that is attached to the 1x4 frame that is attached to the studs, the screen adopts the curve as well and the tension of the O-rings holds everything tight. I know this sounds complicated, but its really extremely simple and I'm still not sure why nobody else builds them this way.

-Sean
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post #6 of 12 Old 07-09-2012, 06:05 PM - Thread Starter
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Mmkay, I'm usually a visual learner but I think I followed what you did. Looks like I can skip a step and perhaps some lumber by just lining up the 2x's along a marked out curve based on Aussie Bob's spreadsheet. So, you tensioned the screen on the 1x8 frame, then screwed it into the 1x4 frame and it still maintained its shape, or did you screw in the border, then install the fabric? Looks a little tight to do that, but...

In terms of the picture frame hooks, did you lay out your screen, then add the hooks one at a time while tensioning or add them all by accounting for a certain amount of stretch then adding the screen once all the hooks were on? Again, I really appreciate your help. I am totally going to emulate this build. Summer is a bit busy with camping and family stuff, but I'm gonna start gathering stuff up. I hope to have it done by the time Avengers 3D comes out on Blu Ray. Can't wait for that one. Cheers.

PS - if you could post a quick pic of your grommet/O-ring/D-ring/picture frame hook setup, that would be fantastic. I'm having a hard time visualizing it.

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post #7 of 12 Old 07-10-2012, 10:38 PM
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My build is documented here in this forum. The frame is steel but the welding is pretty simple. I used o-rings to attach the Seymour XD fabric.

Cheers.

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post #8 of 12 Old 07-11-2012, 08:24 AM - Thread Starter
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Moggie,

Yes, I saw your build thread. It was amazing, but definitely out of my skill range. I see how you attached the O-rings, so that is definitely helpful and may be the way I'm going to do it. It looks like you were able to stretch the material on the concave side without a hitch, so I may go that route as well. Thanks.

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post #9 of 12 Old 07-16-2012, 04:46 AM
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I don't have side masking, but HERE is a link to my curved AT screen.

Whilst I used a proper alloy frame, I have also made similar screens with timber (which curves easier).

Mark Techer

I love my Constant Image Height system!
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post #10 of 12 Old 07-16-2012, 04:49 AM
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Quote:
Originally Posted by John Schuermann View Post

I don't know the answers to your DIY screen material questions, but the reason you now have black bars is that you changed the throw ratio. Throw ratio also affects aspect ratio.

John is correct because as you decrease the Throw Ratio, Grid Distortion also goes up and it is the GD (assuming you framed the image based on the width) that changes the AR.

Mark Techer

I love my Constant Image Height system!
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post #11 of 12 Old 11-02-2012, 05:59 PM
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Here is a link from SeymourAv
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post #12 of 12 Old 11-04-2012, 08:41 AM
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blastermaster - Did you build yours? Sorry missed this thread earlier.
My 130" DIY curved screen journey is captured here.....
http://www.avsforum.com/t/1029683/diy-curved-screen-with-structural-extruded-aluminum-metal-framing/30#post_15186244
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