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projector throw distance , how crucial ?

Discussion in 'Projectors, Screens & Video Processors' started by rob12770, Oct 15, 2005.

  1. rob12770

    rob12770
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    hi, im planning to move my barco data 650 into the bedroom and knock a hole through, then i could use a fixed screen and the pj would be silent, but this means the pj will be about 3 ft further back, i assume this would make the image bigger, but my pj has the ability to scale down the screensize, with h+v adjustment, is it ok to do this ??
    cheers rob :hiya:
     
  2. Mad Mr H

    Mad Mr H
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    sort of........

    If you are not bothered about the condition of the tubes in time or its resale value.

    CRT's are a fixed throw system

    Yes you can change this but thats not really what they are built to do....

    Further away so you will use less tube area, this will reduce brightness and resolution, and cause a poor wear area.

    you should think about a screen a foot wider or consider a lens change to a short throw set.

    Is the move to reduce the noise?

    seems like a lot of work.

    What are your main reasons?

    If noise then maybe consider a fan change - even a direct replacement is often an improvement over old fans.

    Forgot to mention - throw distance crucial? YES - the projector will only ever perferom at its best if the physical set up is first correct otherwise you are wasting your time.
     
  3. rob12770

    rob12770
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    main reasons?
    well its a horrible machine on a huge bracket i made above the couch, i cant ceiling mont it , ( concrete joists) and would like to hide it :) but i have a relativley small room, :rolleyes:
     
  4. Mad Mr H

    Mad Mr H
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    do you mean a "beam and block" floor above?

    do you have a picture of the current setup?

    And screen size and distance....
     
  5. rob12770

    rob12770
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    yes here, but its embarrasingly ugly :rolleyes:
    http://www.avforums.com/forums/showthread.php?t=175221

    and the joists above are wood and concrete, but its rented anyway so i dont want to wreck the cieling :eek:
    also i feel it could be safer, although its been up there over a year..
    5 foot screen, but i want to put up a fixed screen , nice and flat, i can only do this if i move the pj, but i can make the screen any size, throw distance ( if in the bedromm is about 150 inches
     
  6. Mad Mr H

    Mad Mr H
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    HI,

    Your bracket is OK, yes ugly but then so am I!

    Its all about the picture.

    If you were worried about the ceiling mount as it is a rented place - you really think knocking a hole through the wall is better ???

    Anyway - you could tuck/cable tie the cables down one of the side vertical mounts or in trunking that would tidy it up a bit (you might have done that already)

    did not see your screen but a fixed screen is always an excellent idea.

    think you should stick with what you have - OR time for a new pj.

    A nice smart small seleco ;)
     
  7. fortean

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    Hi Rob,
    I ceiling mounted mine by having bolts through the ceiling to the floor above. I had a friend weld some washers on to M8 threaded bar of the right length. On the floor above I used a spade bit to remove 2mm deep by 20mm diameter circle of floor board around each hole so that the washers would be flush.
     
  8. rob12770

    rob12770
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    yeah, i will get a new pj, but , i would like to get the final position first, i have tried a lot of rolled screens manual and electric, but none of them as as flat as a fixed, ultimatly thats what i want,

    as to the hole in the wall, its really just a few bricks above a double doorway into the bedroom, and no its not rsj strengthened as there is a concrete/ steel beam above that, so not load bearing in any way, but the ceiling would have to be cut away, joists strengthened, etc, obove me is a childrens nursery so i cant access it :rolleyes:

    my initial question was, if i set the pj 3 feet further back, and downsize the image with the internal controls, will this be a problem , ie, will the focus be as good ??

    cheers rob
     
  9. Mad Mr H

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    focus should remain the same - HOWEVER like my initial answer loss of brightness and resolution. I dont think that is a good way forward.

    you should increase the screen size by about 1 foot that would help.

    if your screen is currently 16:9 then moving the pj back and adjusting H&V will have a bigger (poor) effect than if you use 4:3

    distance away from screen is the first thing to get right when doing the phyisical set up - dont play with nature!

    btw : What input do you use?
     
  10. Mad Mr H

    Mad Mr H
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    or even try a painted screen on the wall.

    by that I dont mean brilliant white from B&Q I mean a proper screen reflective paint.
     
  11. rob12770

    rob12770
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    my input is htpc, 800x6000 ati card , i would make a blackout cloth screen with black velvet borders as i find this to be very good, :clap: i use 4:3 .

    my other concern is that i dont want to go any bigger in screensize as it may be uncomfortable to watch as i am only about 11 ft away from the screen,
    i guess il just have to experiment, as you can imagine, i cany put a fixed screen infront of the double doors, hence wanting to relocate the pj.
    cheers rob
     
  12. Mad Mr H

    Mad Mr H
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    800x6000 wow that is unusual!

    OK I know what you meant.......

    I have an 8 foot screen - front row of seats is about 8 foot away, middle row is about 12 foot away, both are fine to watch 3 films in a row - the seats matter.......

    I use 1024x768 (ish - cant remember) currently from a BD801s with G upgrades

    if you move it back I really think you will not be happy with the final picture





    SORRY - I just got this, please confirm....

    You sit 11 foot back from the screen, you projector is about 11-12 foot from the screen....your screen is 5 foot across?

    as a standard rule of thumb CRT projectors are positioned 1.5x the width of the screen away.....

    I think you should check your setup OR tell me where I have misunderstood you......

    sounds like the PJ might not be in its prefered position for your screen size?
     
  13. rob12770

    rob12770
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    no, it probably not at the preffered position, but im limited as to here i can put it as its a wee room, i have already adjusted the h +v size on the pj to reduce size, so the whole face of the tubes is not being used..not much choice, i cant move it it any closer to the screen, anyway ive probably caused burn in by now and this would show..

    but according to the barco installation manual, i have it in right place, hmm
    right now from screen to projector front foot, it is about one and a half times the width of the screen, so thats good, but thhe raster image has never filled the face, strange huh ?
    rob
     
  14. Boy Lex

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    I think a rethink is in order rob... I've half built my cinema in the sitting room - sone some cabling for speakers and put the screen up above my fireplace... the projector is table mounted at the mo behind the sofa, but I need to put it so far back it sits under the divide between my sitting room and dining room... I was thinking of doing some crazy things like mounting it in the attic pointed downwards with a big mirror redirecting it to the screen... I've just decided I'm just going to move the screen to a different wall and move the whole room around as it'll be easier... My new idea may be even better as I think I might be able to put some sort of airvent in to run it quieter.
     
  15. Boy Lex

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    Also... don't be so sure - if my little experiment with my 701s shows nothing else it's just how difficult it is to burn a crt tube. You'd have to be running it very bright and for a very long time I think before you'd notice it... Peer down the tubes with a maglite and have a look.
     
  16. rob12770

    rob12770
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    my thoughts exactly mate ,an almost identicle situation :)
    i have to take the lenses off anyway, to get it down (really cuts down the weight) il have a look then.
    cheers rob
     
  17. Boy Lex

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    Have you got someone strong to help you get it down?!
     
  18. rob12770

    rob12770
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    yeah me and my mate will do it, il take out the convergance board too, crt is by far the best as we know, but man they are heavy lol
     

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