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Thread: Random thoughts

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    Platinum Lounger
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    Random thoughts

    I was pondering the idea of making up a "poor man's" big screen plasma TV, based on one of those PC projectors I saw running the other day. They used just a white painted wall as a screen, and the quality was surprisingly good IMO. Assuming you already had TV aerial/ cable outputs in the room, and your existing sound system + VCR + DVD, what else (including the projector) would you need to set up this "home theatre"? What sort of costs might you be looking at?

    Alan

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    Re: Random thoughts

    Alan,

    Unfortunately, you cannot make a "big screen plasma TV" from a projector. <img src=/S/anigrin.gif border=0 alt=anigrin width=19 height=19> I am sure you meant to either not include the word plasma or to have used plasma-like. I also do not know what type projectors you saw.

    BUT, on a conceptual basis you certainly can use a modern projector to view TV on a wall. It's been done many times and I suspect we can locate several places where you can buy just that sort of thing. Unless you are willing to accept the equation "poor Man's" = some undesirable effects, this approach will not be inexpensive. The affordable projectors are low on lumens and to accomodate that limitation two things are done. First, the room is darkened. Here in the US consumers would not tolerate having to watch TV in a dark room. The second thing that is done is to have a high gain screen which takes the limited available lumens and reflects them back into a limited cone angle where the viewer(s) sit. These good screens also take money out of your pocket. The wall is a Lambertian diffuser and scatters the projector light in roughly 180 degrees wasting much of it. If the lights are ON, that ambient light is reflected off the wall (or screen) where your image will be so that luminance level is what your TV image black level will be, so say goodby to contrast. Low contrast TV is not very enjoyable.

    If the projector you are considering is not designed specifically for TV you will wind up with some motion artifacts if you are talking about a liquid crystal projector. You also need a TV source that is compatible with the projector's electronics and design. In particular, raw TV delivers an interlaced signal while inexpensive projectors may only be progresive scan like your LCD monitor. Money can fix this incompatibility. Your DVD player may have multiple output formats.

    Projectors designed for TV can provide a good solution, but it will cost. A lot of effort is being put in to rear projection TV (projector in a box with folded optics) where the ambient light issue is easier to handle. SO your notion is well founded, though today it must also be well funded.

    Paul

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    Re: Random thoughts

    Here is some advice that will get you started, the cost of home cinema can be as little as

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    Re: Random thoughts

    Alan

    I borrowed an LCD projector from work to run a film night at the Jezzarette's school last year and had it in my house for a couple of months before I returned it. The girls and I used to watch DVD's, TV and Videos on it whilst projecting on the wall. The only real issue I had was the noise of the fan kicking in during a film and the amount of heat it kicked out.

    During one film night, in my rush to set uo, I forgot that the air intake for the cooling was in the base and it began to overheat effecting the screen image. The whole IMHO needs to be thought through in respect to ventilation and cooling. The system will only be as good as the screen as Paul mentions.
    Jerry

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    Re: Random thoughts

    Thanks for all the info folks. As you might gather, I'm pretty ignorant of all the gear involved. That replacement bulb cost is a real killer though. I looked at some big screens today. Pricewise, the projector idea may not really be the "poor man's" choice. I also noted that the dearest model ($10K) was the one with the obvious sync problems - so bad it wasn't worth watching.

    Alan

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