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Question for 7" CRT folks?  

post #1 of 12
Thread Starter 
Would you rather sit 12' feet back from a 54'x96' 16:9 screen using a 7" CRT projector, or sit 10' feet back from a 45'x80' 16:9 screen using the same projector? Obviously the smaller screen will have the brighter picture (screen gains being constant) and should have better focus and resolution. What other Pros and Cons come into play when deciding between these two screen scenarios?


The Academy Home Theater
post #2 of 12
I think you need to factor in the projector, room layout, and personal preference to answer this question.

For myself I choose an 80x45 screen to match my ECP 4101 (7inch CRT unit). The screen wall is only 12 feet wide, so I wanted to have enough space on either side for my speakers to "breath". The ECP is not a bright as say a Dwin which can more easily handle the larger screen (IMHO).

The best thing you can do is get the projector, but wait to purchase a screen. Set up a bedsheet or any other white surface as a temporary screen and play with the throw distance and screen size with the projector floor mounted. This will give you a good idea on screen size that you prefer, as well as getting the throw distance right before you mount the projector on the ceiling.

Putting a theater together is supposed to be "fun" -- so take your time.

post #3 of 12
Wow, a 54 foot by 96 foot screen driven with just a 7" CRT FP. I don't know what kind of projector you have but I'm not sure my Runco 750 would quite do the job. http://www.avsforum.com/ubb/smile.gif

Between the two screen sizes you suggested (converting them to inches), I cast a second vote for the 80" X 45" screen. I have an 80" X 60" 4:3 screen which makes my 16:9 pictures the same size. Keep in mind that CRT brightness drops roughly in half after they age a bit (I've heard figures in the 1000 hour range but that varies a lot depending on how hard they are driven). That's 300-400 peak lumen from a 7" CRT which is pretty marginal to drive even an 80" wide screen.
After writing my comments above, I went to your web site and see that you already have a 96" X 52" screen. Now I'm curious why you are asking this question. How do you like the larger screen? Is it bright enough for you when watching dark movies?


[This message has been edited by dna (edited 01-15-2001).]
post #4 of 12
On the other side of the spectrum, I had a 120" X 67" 2.3 gain 16:9 screen with my Electrohome Graphics FPTV with 7" CRTs and a single lens configuration that had slightly less light output of it's brother ECP4100.

The picture looked fine in total darkness, but was easily washed out with incedent light.

I like bigger screens, so I'd pick the 96" X 54" 1.3 gain screen (and sit at 10' away). But this does relate more to personal tastes than anything else when you are not going with a huge screen.

I'd second Andrew's idea of setting up a sheet to get a feel for what size suits your room, tastes, and picture quality/resolution.

Often a line doubler or HTPC will add brightness to the picture having more active CRT phosphers lit up.

post #5 of 12
Yes, I second that. My HTPC running at 1800x1200 made for a decently bright picture that was very dense, on my ECP 4100. The NEC gp-5000 is just marginally brighter, but immensely more natural appearing. Higer frame rates are a bit of an interesting factor as well.

I am using a 1.6 gain screen. at about 85-96" across. It varies....no masking. I don't suffer from much washout.

---Place Signature Here---
post #6 of 12
Thread Starter 
Andrew & David,

Yes, I already have a 52"x96" (1.85:1) Draper M2500 (2.3gain) screen and I am happy with the screen to a certain extent. Since this screen was my first ever FPTV screen, I had nothing else to compare to. I have seen some Stewart Studiotek 1.3 gain screens lately and I like the lack of hotspotting as well as the color uniformity and the screen material itself simply disappears when watching programming.

I could use the same screen size, though I would opt for 16:9 this time around, but I am looking to gain a brighter and sharper picture. By going from a 2.3 gain to 1.3 gain screen with the same size dimensions as I'm currently using, the brightness would surely be worse and I would have to drive the projector even harder.

I wouldn't classify myself as a videophile (maybe a videophile in-training) http://www.avsforum.com/ubb/wink.gif, but I am trying to tweak the best picture out of my projector (which only has 675 hours). I feel that the closer sitting distance to the smaller screen will give me virtually the same optical view as the farther viewing distance from the larger screen, while gaining a brighter and sharper picture with more apparent resolution.

I know I sound like I have already made up my mind, but I would still like more feedback from the more experienced on this board.


I know you're a large (make that HUGE) screen fan. I am however looking for the "optimum" picture quality from this projector as opposed to the largest screen the projector could light up. I guess we all have our preferences.


1800 x 1200 seems like a rather high resolution for a 7" CRT projector. I would think your scan lines would be overlapping causing a rather soft picture. Just curious?

The Academy Home Theater
post #7 of 12

I was just pointing out the edges of the envelope. Which I like to push.

I was originally told that any screen over 84" diagonal would be overdriving the (7" CRT) projector. But I also had a Draper M2500 screen, and at 16:9 68" X 120" it looked brighter than my original 4:3 72" X 96" 1.3 gain screen.

But as you metioned, the cost was some hotspotting and colorshifting.

I agree that if you are shooting for an "optimal" picture, you could go with a slightly smaller 1.3 gain screen, and just sit a little closer.

It would still be a big picture, and you would minimize the hotspotting/colorshifting issues.

post #8 of 12
You would very much think so. It appears, after a bit of experince, that what most see as overlap is partially poor electronics. I changed over 350 components in the 4100, and now it really cooks.

The ECP convergenge grid pattern lines are at just a hair over 1/8" across, on a approximately 100" convergence pattern. This is at normal brightness/contrast. (the internal generated settings are a bit lower than that of the input card/projector combination, in this particular set-up).
As you may imagine, the weather changes and the image goes off.....

---Place Signature Here---
post #9 of 12
I am a lover of THE BIG SCREEN. The bigger the better. I have a Stewart Fixed 60x107 Micro-Perf Silver 400. This has a gain of 4.0. My PJ is a Zenith PRO900X with 7" CRT's.

The negatives of a high gain screen, to me, are far out weight'd by the positives like the increase in Contrast Ratio, Brightness and Bigness of the screen. I would have loved to have gone bigger but the room just wasn't wide enough.


post #10 of 12
You must be one of those folks that likes to sit in the front of the theater.

I've just finished installing a sony 1271 (7" CRT) and I reduced my screen size from 45x80 to 40x72. I'm watching from 16 ft and for me anything above 40x72 was just too much...it gave me headaches and eye fatigue.

The smaller screen size is brighter and does look sharper.

Good luck

post #11 of 12
Originally posted by jcastle:
I've just finished installing a sony 1271 (7" CRT) and I reduced my screen size from 45x80 to 40x72.
I would go to a 72" rather than my 80" wide screen for my 7" Runco 750 if I were to do it again. However, I have a unity gain screen and the FP doesn't support HD resolutions. I'm curious to know, Jason, what your screen gain is and whether you display HDTV? If not and/or if you had a brighter picture, would you want a larger screen?


[This message has been edited by dna (edited 01-22-2001).]
post #12 of 12
Thread Starter 

Stewart custom cuts every screen they sell. They do not charge extra for custom sizes so you can get any size you want!

The Academy Home Theater
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