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-   -   Now less then thrilled with M2500 (http://www.avsforum.com/forum/23-screens/18822-now-less-then-thrilled-m2500.html)

Dylan 10-25-1999 09:58 PM

I posted a message a few days ago stating how pleased I was with my new M2500 screen. Now after a week of using it I'm less thrilled. There are two image problems I've noticed:

Hotspotting: My projector is on the floor and my eyes are below the center axis when seated. Because of this, the hotspot is below center. This makes the upper portion of the image particularly dark. When I stand up such that my eyes are above the center axis the hotspot falls pretty much in the center of the screen and the light dropoff towards the edges is less objectionable. The best illustration of the dark upper portion of the image has been the World Series. The batter is in the center of the image and the pitcher is near the bottom. The hotspot from my seated position falls between the two. So what happens is that the already darker stands behind the batter are really dark. I compared the image to my direct view TV and while the fans are easy to distinguish on the direct view they are murky on my FPTV.

Color shifting: This one is a much bigger problem. There is a significant color shift from red to blue (left to right). It's very obvious with an all white image. It's generally not too noticable with moving color source material. But I find it objectionable with B&W source material. I watched Blair Witch over the weekend and the color shift was noticable and distracting during the B&W 16mm portions of the movie.

The hotspotting is a minor problem. For this and other reasons I'm probably going to end up mounting the projector on the ceiling. I was trying to avoid this because the low (under 7 feet) ceiling in my basement.

I guess I'm just going to have to live with the color shift. I'm surprised that I haven't seen this mentioned by others as a bigger problem. I consider it pretty severe. If I watched a lot of B&W material it would be unacceptable. As it is, I still think the tradeoff between these problems and the brighter image is worth it. But it's a close call and I definitely wouldn't give this screen material an unqualified recommendation. My recommendation to others with CRT projectors would be to only go this route if you really feel you need the higher gain screen and realize that the higher gain doesn't come for free.

My projector is a Sony 1270Q, floor "mounted" about 95 inches from the screen and I sit about 130-140 inches from the screen.

-Dylan

Dylan 10-27-1999 12:38 PM

I am using a DVDO iScan. I haven't tried it without the doubler and I don't have the cables necessary to make the connection.

I am going to be moving my screen back about 8-10 inches soon. I'll see if this makes a difference in the color shifting.

-Dylan

DMan 10-27-1999 01:33 PM

I use a Draper M2500 and experience virtually no hotspotting and absolutely zero color shift. For reference I am using an NEC 6PG Plus CRT projector, DVDO iScan, and the projector is ceiling mounted and has been ISF calibrated.

Even my ISF tech commented about how good the screen looked. And just this past weekend I picked up an RCA DTC-100 and experienced Monday Night Football in HDTV for the first time. One word...awesome!!!



------------------
DMan
The Academy Home Theater

Alan Gouger 10-27-1999 03:29 PM

Dylan
You can tilt the top of the screen out from the wall a little bit to add a little keystoning. This will eliminate your hot spotting.

Dean McManis 10-27-1999 05:44 PM

Dylan,

My Electrohome CRT FPTV had a single lens arrangement, which reduced any color shifting.
Now with my new Sony 1292Q I see a little more visible hotspotting, but it's not objectionable to me.

I haven't noticed any color shifting with the M2500 on either projector, but the finer convergence controls on my 1292Q allow tighter CRT alignment which shows up best with B&W movies.

-Dean.

BL 10-27-1999 09:29 PM

Dylan:

I am in the process of getting a Sony 1272Q and need a screen, so I am interested in your experience. I could not tell from your post whether you are using a line doubler. Are you, and if so, what kind? Do you notice a difference in the problems with it on or off?

Dylan 10-28-1999 10:48 AM

Alan, thanks for the tip on reducing the hotspotting. I'm going to remount my screen this weekend and I'll give it a shot.

Can anyone explain why I seem to be experiencing worse color shifting than others with the same screen? With an all white image the left half is clearly tinted red while the right half is clearly tinted blue. It's very noticable with B&W material. Is there something I can do to reduce it?

-Dylan

Alan Gouger 10-28-1999 06:09 PM

The only thing I can think of is going with a longer throw. The drawback would be having to reduce the raster size on the suface of the crt.

David Bott 10-28-1999 06:46 PM

Dylan:

I also find it interedting that you say you have such issues. Esp the color shift. I run an XG135 at 14 feet back from the screen. I am ceiling mounted and do not have anything you have stated. (Screen is 8 foot wide.) Also, on the XG line you can control the color shift across the screen so maybe that has something to do with it.

But in any event the M2500 has been one of AVS's best sellers and we hear very little, if any, complants about it. It get more cheering than anything. http://www.avsforum.com/ubb/smile.gif

It could very well depend on the angle of attack from the project to the screen and tilting the screen as Alan states may just help you. Good luck on getting it setup so you are happy with it. I think you may like it better ceiling mounted. http://www.avsforum.com/ubb/smile.gif

------------------
David Bott
It's A World Of Entertainment...Experience It!
AV Science Webmaster
http://www.avscience.com
http://www.bott.net

Laurence 11-02-1999 02:52 PM

I thought that glass-beaded was improper for video (too much light scatter)and was designed for slide projectors.

Mark Rejhon 11-02-1999 09:43 PM

Yes, the projector should be cieling mounted for the M2500 to be at it best.

Currently my projector is waiting to be installed on the cieling. I've seen the same result - the top edge being dimmer.

When I visit one of the 3 home theaters that are based on M2500's (all have cieling mounted projectors) I do not see the problem. Nor I do see the problem when I am standing up behind the projector.

So it's definitely the floor mount - that's a very bad configuration for a M2500.

------------------
Thanks,
Mark Rejhon
www.marky.com


Larry Davis 11-02-1999 10:44 PM

An ISF calibrator/installer told me point blank that if I went with a high gain screen(1.8 and up), I would have to ceiling mount the projector. If I wanted to floor mount the projector, I needed to go with a lower gain screen (1.5 or less). Otherwise, the image would be unacceptable.

Larry

kromkamp 11-03-1999 02:05 PM

The Da-Lite High Power screen is a 2.9 gain Retro-Reflective screen. I like it quite a lot. Its not glass-beaded, but a variation thereof that eliminates sparkling and screen structure.

I had my projector floor mounted, and was happy with it, but at the same time there was a small decrease in brightness between putting my head right beside the projector, to where my head is when I'm sitting down.

My projector is somewhat dim and I'm driving a pretty big image, so I wanted to get every bit of brightness I could. I've now mounted it at head level, behind me, and I'm very happy with that.


duckjibe 11-03-1999 02:55 PM

If you use the same geometrical relationships (dimensions and angles) between you(the viewer), the screen and the projector, then the location of the projector (ceiling vs. floor mounted) should be totally transparent vis-vis picture quality, hot-spotting and so on. The critical parameter here is NOT ceiling vs floor mounted projection, but rather the resulting geometrical arrangement. Moreoever, a caveat here is : It may not be possible to achieve the same geometrical relationships in your specific case.

Frank.

threed123 11-03-1999 04:27 PM

I have a 1270q, floor mounted with a high gain (about 2.5) retro-reflective screen, and I get no hot spots, however, I used to get color shift until I re-adjusted the lenses to fit the correct screen size. Sonys require that you adjust the red and blue lenses slightly in or out, (mechanically through screw adjustments) for the convergence angle you require. If you don't do this, you will end up shifting the red and blue images slightly off-axis--this I believe causes the color-shift. This is street-gut info--what do you ISF folks think about this?

PJ 11-06-1999 10:50 AM

Hi Guys.

I run a 450 ansi Lcd proj and i choosed a 1.0
gain screen, no problems with hot spotting or anything. Why do people choose hi gain screens when they have the good proj´s with a lot of lightoutput?
Go for low gain screens and u will have no probs with angels or spots etc..
Works for me http://www.avsforum.com/ubb/wink.gif

Pj

[This message has been edited by PJ (edited November 07, 1999).]

Dylan 11-08-1999 05:31 AM

threed123, can you post the procedure to do this adjustment? You're not talking about the spacers, are you? That's the only adjustment for screen size that is mentioned in the installation manual. I was surprised that the manual mentioned no physical adjustment necessary for convergence before the electronic adjustment. It would seem that you would get better results if less electronic compensation was necessary.

-Dylan

Johan 11-10-1999 04:05 PM

I ordered my Draper 2500 screen 133" On OCT the 12th via AVFORUM Quik Store.

I got a confirmation of the order by email, but still no news of delivery. I'm dying to try it out on my 400Q "similar" machine.

It's supposed to be UPS expressed...

I have been reading these forums steadily for a while now. The M2500 has got to live up to its name. Keep you posted.

Mark Rejhon 11-12-1999 07:00 AM

Johan,

Was the 133" a special order size? It can take more than one month for a special order size to ship, as it has to be manufactured at the factory.

Dylan,

When my projector is moved to a new position, I really have to do physical adjustment first to get the picture in focus well and the mechanical convergence into the "ballpark" necessary for me to read the onscreen menus... (they are impossible to read if I start electronic adjustment before physical adjustment). Then I do the electronic adjustment to reset the electronics to baseline. (ie, static convergence to 0) Then I readjust the mechanical to precise proportions. Then I do a real big fine-tune of the electronic adjustments.

------------------
Thanks,
Mark Rejhon
www.marky.com

[This message has been edited by Mark Rejhon (edited November 12, 1999).]

Dylan 11-16-1999 08:55 AM

Mark, what you say seems logical and it was what I was expecting before I got my projector. But the only physical adjustment described in the Sony installation manual is for broad ranges in screen size. Does anyone know of more physical adjustments that can be performed to optimize the Sony 127x projectors?

-Dylan

Kent Mascotto 11-16-1999 11:30 PM

Dylan,
Optimize.. In what way were you thinking? When you say physical adjustments are you referring to focus, size or something else?
The only need to change the red & blue spacers on the sonys are for better convergence on larger or smaller screens. Stick to the install manual ie. 109inchs throw distance for a 100'' 4:3 screen or 129inchs for a 120'' 4:3 screen (factory setting) Save your self a lot of time and reset every (i mean every setting to the factory reset) This will really make the convergence simple. The spacers should be at their M (medium) setting. Then do the lens focusing and lastly the electrical focus (RED & GREEN Only) do not touch the blue focus, you will only through off your gray scale.
Kent
Dylan,
I copied a post that I did some time back, I hope this helps
The procedure described below is for a sony 1271.
BTW: which manual do you have?

I'd like to start a convergence technique thread to see how others on this forum are setting up their projectors.
My first experience setting convergence was with a sony 1020. It being completely analog and having to adjust 50 different pods (dials),it worked as a great learning experience. Some what like learning to drive a standard before getting behind the wheel of an automatic car. The second projector I had was an Electrohome Marquee 8000, this baby was a Cadillac, very very user friendly. What I really liked about it was its detailed user set up menu. I'm sure, the techniques that I learnt from this unit are transferable to other projectors. So,if I miss some thing please fill in the blanks.The first thing you are going to find,(after getting the projector home for the first time) is that when the power is first turned on, and if projector has a menu system you will not be able to read them because the focus will be so far out of wack.
Therefore you will need to set the unit up for the correct distance from screen(see manual for recommended distance). Then manually adjust the focus (ie.lens focus), inside lens first(center of picture) then outer lens second(edges of picture). (THIS IS WHERE YOU NEED TO RESET EVERYTHING TO THE FACTORY SPEC'S)Under each control feature press the < > keys at the same time (do this twice to make sure it's done right) sorry i was not trying to screaming.
Reduce the contrast & brightness and then look into the tube (green) and center the picture(square) in the middle of the raster(round) (ie. make the square fit evenly inside the round viewing surface). Now do the red & blue. You will now need to turn the contrast & brightness back up. With the cross hatch pattern now showing on the screen, aline the center vertical red line of the cross hatch with the center vertical line of the green, it should be close to start with. Now do the same with the blue. The green patterns are always used as the reference(every thing is alined with the green). What happens when the green is all screwed up your thinking? Well this is what I do, I take string,a carpenters level,some tacks,weights for the string and a tape measure. The first thing I do is build a hatch pattern. Find the center vertical and horizontal area of the screen. Stick a tack in the ceiling with the string and the weight attached, this string will hang down the middle of the screen, now if your picture is to be 80inchs wide, then measure 40inchs on both sides of the string and place tacks in the ceiling with more string hanging down from these spots.You now have 3 perfect vertical lines(one in the center and the 2 outer making up what will be the left & right edges of the picture. This will have to be done for the horizontal center, and top and bottom edges. Use the carpenters level on the center string, again measure 30inchs above and below the center string, locating the points where the top & bottom string lines will be placed(which you will have to tack to your walls). The end result will be a perfect grid with which to aline the green cross hatch to. ( Some people use post-it notes instead of the string)
Remember to set all values to the center or middle of their adjustment range, before starting.
Green cross hatch to string alinment
1) size control (vertical & horzontal)
2) linear control (vertical & horzontal)
(hint:use tape measure for cross hatch box size top/bottom & side/side)
3) keystone
4) skew
5) bow
6) pin
You will now need to aline the red to the green, then do the blue to the green (shut the red gun off when working with the blue and the blue gun off when working with the red)

And last is the zone convergence, again red to green then blue to green.

If you need a copy of a dealer install manual let me know
Kent

[This message has been edited by Kent Mascotto (edited November 18, 1999).]


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