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Rear projection Rigs

Discussion in 'Projectors, Screens & Video Processors' started by buns, Dec 25, 2003.

  1. buns

    buns
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    Just a meander in my mind...... I cant fit crt in the traditional sense....... but what about rear pro?

    I recalled having read about Paradigm doing such things from an old HCC article...... so had a look and yeah, they make frames and systems and whatever you like. Draper seem to make something not dissimilar. The only thing I so far cant find is an idea of the prices. Does anyone have any idea what sort of money we are talking about for an 80 odd inch wide frame? Are we talking £1k or 10k?

    On the same note..... im presuming that the use of such a system gives more scope for getting a good image given the lack of light leakage..... so would this technique even help to improve a middle ground lcd?

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  2. ReTrO

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    The biggest cost in these seems to be the screen material. The really good DNP screens that Paradigm, amoung others, use cost from upwards of around £3-6k. Plus there's the cost of the mirrors, shoudl you neec them.

    At the lower end of the budget are the fabric screens which can be upwards of £300 ish for the lower end stuff. Rigs are extra of course.:smashin:
     
  3. buns

    buns
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    well i was thinking of fabric screen but wondered how much the frame/mirror would cost.......

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  4. ReTrO

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    Best get a good idea of prices from someone in the dealer area.

    Rear-pro screens not my area at work sadly.
     
  5. johnsattuk

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    I am experimenting with rear projection at the moment. I have just bought some fabric from 'screensuk'.

    Great picture, cost £200 approx for 6' x 5'
     
  6. buns

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    i got some rig prices inc screens....... $7-10k :eek:

    id definitely build one if thats the sort of silly money!

    John, space is an issue for me, the screen is the easy part, but id need a mirrored array to get a picture to it!

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  7. Chris Frost

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    It is possible to build a rig yourself. The expensive bits are the front silvered mirrors and the screen.

    Like johnsattuk and ReTrO said, screens vary.

    From personal experience I found fabric/vinyl screens tend to billow a bit when you open/close the door to the cinema room. I also find they give the most restricted viewing angle. Great when you are on axis, but lose a bit of brightness when viewed from the sides.

    DNP screens are without doubt the best. Widest viewing angle, most vibrant picture, best focus and great uniformity. But of course, they're pricey.

    In the middle you have solid diffusion screens. Less prone to movement than fabric and lower cost than DNP. The trade-off is performance. You'll see them used in shopping malls as a low cost an alternative to DNP HoloPro, but need high power LCD or DLP projectors to overcome the brightness loss.

    Regards
     
  8. johnsattuk

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    As Crhis said, the fabric is prone to billow a little when doors are opened closed, I also find a little hot-spotting and colour diff. across the screen, the actual image is quite good,

    I borrowed a sample acrillic diffusion screen from JVC that had none of these faults with a wonderfull image, I am just saving up the £2000 to get one.

    I have not tried DNP types, but I think they mostly require the projector on axis, not aproblem with mirror rigs I supose

    As they say you pays your money

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  9. buns

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    surely though...... the issue with a billowing screen is no more of an issue as it is for a front projection set up......

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  10. johnsattuk

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    I don't really notice enough to be a problem since there is not much movement about the house when veiwing, also in my case I have the screen tensioned in a fixed frame. My screen is part of a room divider so is perhaps more prone than a screen close to a wall. As I said I don't find it a problem and had not thought much about it till Crhis mentioned it.
     
  11. Chris Frost

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    The main reason to go rear projection is to allow viewing in higher ambient light than conventional front projection allows without losing the black level. This normally involves building an enclosed projection booth to prevent light leakage, so you end up with a big sealed box with one flexible wall.

    This means you have a potential air pressure difference between the projection booth and the viewing room. Opening or closing the door to the viewing room causes an air pressure change in that room; hence the screen billows.

    For front projection this does not occur. The front and rear surfaces of the screen are subject to the same air pressure - that of the main viewing room - so the only time the screen wafts back and forth is when there is a draft.

    Regards
     
  12. johnsattuk

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    Thanks Chris for a very definitive explanation, I had not thought about pressure differences, since my screen is in room divider with plenty of openings round it, probably why it only billows a little
     
  13. buns

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    fortunately all this sort of thing wouldnt be an issue, since where i would do it would have 2 separate rooms fed from the same single air source...... so what happens on one side happens to a similar extent on the other...... all sounds too expensive unless i buold my own though

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