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Would like to use a decent quality CRT (Nec XG, Sony G70, D50, 1272) as a Rear Projector.


Ideally, I would project from another room onto a rectangular cutout/ Screen in my viewing room.


ADVANTAGES:

Optimally setup throw distance and projector height without compromise for practical or aesthetic considerations


Little or no noise


No concern about CRT Radiation (VLF, Very low Frequency magnetic fileds) Does anyone else think that this is a big deal? or is it just me?


It looks really cool to have a huge screen on your wall without anything else in the room.


QUESTIONS:

Are there any special considerations to doing this?

Are there dedicated screens to doing this?

Is the picture quality comparable to front projecting, or are there brightness or hotspot issues?


Any of your thoughts appreciated


Thanks,


david
 

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I think there is a guy in the classifieds selling some big screens designed for rear-projection for about $600.


My understanding is that rear-projection will be a lot brighter, equivalent to a regular RPTV, so light control shouldn't be an issue either.
 

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Quote:
Originally posted by djordan


No concern about CRT Radiation (VLF, Very low Frequency magnetic fileds) Does anyone else think that this is a big deal? or is it just me?
I can't think of anything about a CRT projector that would be VLF except the vertical scan waveform, which isn't very high power.


Personally I'd be more worried about the X-ray emission of a CRT which comes out the front. That's why most CRT PJs use 'only' ~30kV power supplies; the old ECPs which used ~40kV HV to achieve really high brightness were (apparently) found to emit almost enough X-rays to moonlight in a radiology department.


I exaggerate... a little. Personally I think the issue of X-ray emission is far more important than VLF. But if you're really worried about VLF, ground your PJ properly. The sources of VLF are all within lovely steel cages inside the PJ.


BTW, if X-rays concern you, a number of companies sell mirror setups which allow you to mount the PJ vertically, thus shooting the nasty green-tendrils-in-your-descendants-inducing rays out through your ceiling... or into your bedroom upstairs if you're unlucky. :)

Quote:


It looks really cool to have a huge screen on your wall without anything else in the room.
Yes, at the cost of losing an entire room next door to your viewing room. And you still have to put your speakers somewhere. Still, it's a major appeal of RP setups.

Quote:


QUESTIONS:

Are there any special considerations to doing this?

Are there dedicated screens to doing this?
Yes. Lots of different screens, of varying quality and gains.

Quote:


Is the picture quality comparable to front projecting, or are there brightness or hotspot issues?
A high gain screen will result in a narrow viewing arc in an RP setup. You shouldn't have 'hot spots' per se, but the higher the gain the more likely people sitting off-axis will see a dim image.


Also, some screens have a coarse 'grain' which can obscure fine detail. YMMV, you might want to ask in the Screens forum, and you should certainly see demonstrated any screen you want to purchase before you buy.


- David Eddy
 

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One reason not to do it: The good quality rear-projection screens (that approach the same quality as front projection screen) cost a fortune.

Example: A 'regular' 1.3 gain Stewart screen of average size may cost you around $1K (guessing here) and is said to be the best you can get.... something of close to similar quality in rear projection can easily cost you $5-10K. It'll never be quite as sharp. Close, but not 100%.


Check out the screens forum for more info...


Kal
 
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