CurtPalme.com Home Theater Forum

betel

Fellow CRTer's,
I have a lead on a 96" x 54" Vutec torus screen with a gain rating of ~13. The screen is local to me. Currently I'm using a 96" x 72" Dalite Permwall Da-mat screen with a gain rating of ~1. The projector is ceiling mounted in a completely light controlled room. From reading the screen forum here, I know generally as screen gain increases, several problems develop; light levels decrease rapidly as the viewer gets further from screen center along with color shifting & hot spotting. A torus surface is an attempt to minimize these effects. However, the big plus of course is a very dynamic image and being able to run the projector with low brightness & contrast settings. My theater's viewing angle is very narrow so limited off axis viewing should not be a problem.

Evidently these screens are rare and no longer manufactured so determining a value is difficult. And I may decide I don't like it once I install it.

I have a couple of questions for anyone with experience using these types of screens with a CRT projector.

1. Will I have any trouble getting the geometry/focus correct on the curved surface screen.
2. Any idea the market value of the screen assuming it is in good condition.
3. What is your opinion of the overall image quality?

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I will guess that is Wireless's old screen. You might want to check Chuchuf's thread on AVS fronm around 2004.

1) The 10Fs should be ok from what I have read. They are supposed to be better than everything outside of the 900s.
2) I doubt it has to much value. They are somewhat delicate and shipping is expensive along with crating. A guy on here sold one for $400, I think. Also, they are pretty much worthless for digital.
3) According to Terry, he got 30ft/lmbs. With reduced br/cr, the image should be outstanding. I have no idea how narrow the viewing cone is. You will have to see it in action.

betel · Posted: Wed Nov 24, 2010 3:46 pm Post subject:

Thanks for the insight Spanky. You are correct for the screen source (the crt community is a very small world). I'll see if I can locate the AVS thread. The seller did mention Terry F. set everything up and was getting the light levels you mentioned. I don't have a good feel for light levels but my understanding we typically have levels in the 12ft/lmbs range so 30ft/lmbs must certainly be very bright.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Yes, the crt world is pretty small, but I just remember that thread. Plus, he was one of the few Vutec torus owners and I have an affinity for torus screens. Finally, I remembered he was in Ten and probably not to far from you. Just kind of added up, although it took me a second to remember his name. Smile

Has he taken his system down? I would check it out first to see if you like it. These things used to cost a couple of thousand dollars, but the market for these is smaller than CRTs. I wouldn't pay over $400 and might not even go that high especially when I can build my own for about $100.

betel · Posted: Wed Nov 24, 2010 10:49 pm Post subject:

I think he sold some of it and the rest is in storage. Something about getting married and it doesn't fit into his new lifestyle. I'm meeting him Friday to take a look at it. Only about twenty minutes away. You want me to let you know what else he wants to get rid of after I take a look? Apparently he had some very nice equipment.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I probably don't want anything. You might take an inventory and see what has any value. I would love to have the screen, but logistics and price are killers.

betel · Posted: Thu Nov 25, 2010 2:54 am Post subject:

Read some of the archived post you mentioned. Now I'm getting anxious to get it set up.

Tom.W · Joined: 09 Mar 2006 Posts: 6635

I've been looking for one of those screens for a long time. I've always wanted to try one out.... Great find ! Thumbs Up

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

I am sure you will like it, as long as you don't have to big a viewing cone.

Scott may be able to answer this. I would be curious as to what the relationship is between contrast/brightness setting, MTF and resolution.

betel · Posted: Sun Nov 28, 2010 12:11 am Post subject:

Got it! Along with theater seating for three. Working on setting it up now. It came with a stand but I'm going to mount it directly to the wall.

The only thing he has left is an item I can't mention here. He did have a pair of speakers the shipper was picking up for the buyer today. I saw the name but can't remember. Very obscure. Only 37 pair produced. Looked to be very high end. Pyramid shaped bass module on the bottom with an egg shaped mid/high module sitting on top. Real nice guy. He's a bit of a Brady Bunch story. Married a a woman with children and children of his own. They're from 4 to 23 years, six total. He's had all this stuff in storage since he got married five ago. As you know, high end audio/video doesn't mix well with babies, so it had to go.

stefuel · Posted: Sun Nov 28, 2010 1:06 am Post subject:

I've often thought of building one but never get the time to do it. Does anyone know of a formula for the radius of the screen to either the projector or seating distance.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Wow, so he only got to enjoy it for a year or so.

Those speakers are Canadian. I can't think of the name, but it is on the tip of my tongue. They are supposed to be pretty good. I remember when the owner was selling the company and no one seemed to want it.

As for the screen, I hope you enjoy it. I am not sure how good your tubes are, but they will probably last forever with this screen. Wink

Another good thing is that you may not have to defocus the blue tube much or at all with the reduced contrast. Chip, look up pjackso. gary fritz has been touting his spreadsheet for years. Oh if you decide to build one then look into going with aluminized mylar. That is the way Vutec did it to get the ultra high gain.

betel · Posted: Sun Nov 28, 2010 1:24 am Post subject:

Looking at the screen I'd say it was simply the surface of a sphere. Radius maybe 10 feet. Definitely not parabolic. Thinking about it, if it were parabolic, you could get burned or blinded if your eye managed to be located at the focal point. I'll post some screen shots and constrast/brightness settings. May take awhile though.

betel · Posted: Sun Nov 28, 2010 1:32 am Post subject:

The speaker name had "wave" in it. The tubes in my projector are the Eismann high resolution tubes. Maybe 300 hours on them. No visible wear. If I'm able to turn back the brightness/constrast like I think, the tubes should last indefinitely.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

Here is the thread from AVS:

http://archive.avsforum.com/avs-vb/showthread.php?s=5212cd6b74bda330b1241a95c03a1b48&threadid=386394&highlight=torus

Chuchuf · Joined: 11 Mar 2006 Posts: 548

Still love my Torus. It's the Bee's Knee's.

Terry

betel · Posted: Tue Nov 30, 2010 5:12 pm Post subject:

betel · Posted: Sat Dec 04, 2010 1:47 am Post subject:

Update:
Got the screen mounted to the wall. It matches my KEF XQ graphite colored speakers very nicely. Wish I could say something about the image but haven't gotten that far yet. I turned on the projector and noted I will have to move it back a bit to get the width I need. Hopefully I can make some progress this weekend although my other home projects are a bit more important.

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

No excuse!! Smile

I am sure you will love turning down the contrastl/brightness. Wink

betel · Posted: Sat Dec 04, 2010 2:35 am Post subject:

I have messed with it bit although it is far from correct. The angle of the screen is less than I had predicted. The screen is about Perpendicular to the floor for maximum brightness. Initial impression is I will like it. I can already tell the image is much more dynamic. Can't wait to get it dialed in.