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-   -   M2500 mounting options and other questions (http://www.avsforum.com/forum/23-screens/19330-m2500-mounting-options-other-questions.html)

Carey P 01-12-2001 10:52 AM

From the specs I have, the M2500 drops to a gain of 1.0 at 30°. At 60° it's at about 0.8. The fastest drop-off seems to be between 0 and 20°(1.3 gain). I have the M2500 and can vouch for this. I do have a 3-year old model and it does have the streaking effect, but it is really only noticeable in the white scenes, but becomes more intolerable as you go higher in lumen level. For lower output CRT's it may be livable. This screen is definitely too much gain for any projector higher than 600 lumens. That's just my opinion.

I have a tab-tensioned one, and I think it really requires that to keep flat. It is a somewhat stretchable material but is prone to wrinkling and creasing, as well.

Hope that helps. -Carey

MrWigggles 01-12-2001 11:32 AM

Carey P,

Thanks for the info.

How are you generating your answers for 1.3 gain and so on?

Are you placing a white sheet of paper on the screen to be a reference?

Are you assuming that the on axis gain is 2.5 and then going down from there?

If you could please describe your testing procedure, I would apreciate it. If you have results for all degrees that would be very nice as well.

Thanks very much.

-Mr. Wigggles

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The Mothership is now boarding.

Carey P 01-12-2001 03:53 PM

No tests at all. I was simply reading it off a small graph that is given in the Draper product brochure. It is probably not very accurate (as the graph is only 2 inches long!), but seems reasonably close from my experience with the screen.

At the center (which is 0°) it shows a gain of about 2.9 though I know this should be 2.5 (unless they take an average over a certain cone angle). Furthermore, I heard that tests showed this to be more like 2.3 (there was a thread to this effect somewhere). Anyway, this high point on the graph extends flat from -5° to +5° and then falls off equally on both sides to the levels as I described above. It only goes out to +/-60° on the graph.

It is a lot more peaked than the M1300 graph, that's for sure. For comparison, The M1300 starts at 1.3 (0°) and falls off to 1.0 at +/-40° and only gets to 0.9 at +/-70°.

If I'm still not making any sense, I can try to scan the little bugger and post it in this thread.

Carey

MrWigggles 01-12-2001 09:18 PM

How hard would it be to mount a Draper M2500 screen on a curved surface? Does the screen have to be tensioned?

Also does anyone know what the specified viewing angle or more importantly the half intensity angle of the screen is?

And finally, has Draper corrected the streaking problems? I heard that some of the new owners don't have any streaking.

I am considering purchasing the product. Any information you have would be very helpful.

Thanks,

Mr. Wigggles

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The Mothership is now boarding.

MrWigggles 01-13-2001 09:41 PM

Thanks Carey

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The Mothership is now boarding.

Gunnar 01-14-2001 03:14 PM

I have stapeled and taped a 92x69" piece of M2500 material to a wooden frame. The material is rather flexible, thin and is easy to work with. It stays flat on my frame, but I see the streaks..

I have even tried to use the material back side out, and I may perhaps do this permanently. The streaks were gone, and everything else also looked good. A bit dimmer than with the intended, textured side out, but I have recently got a Barco 1200 which puts out 1200 lumens..

I would like to know how much gain I will get from the backside, but Draper say they don`t know. Probably about 1.0?

Gunnar


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