How to calculate height for a wall mount?

Discussion in 'Projectors, Screens & Video Processors' started by mattkhan, Sep 20, 2007.

  1. mattkhan

    mattkhan
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    Hi

    I'm looking at whether or not a PJ without lens shift & with offset > 100% will fit in my room, can someone comment on whether these calculations are accurate? Unit of measurement is inches btw

    So taking the Optoma HD72 as an example, the manual gives the following information;

    Angle of offset (A) = 6.52 degrees

    while my room & desired screen position gives me;

    Throw (L) = 11' = 132"
    Screen diagonal = 88"
    Screen height (h2) = 41.75"
    Distance from bottom of screen to floor (h1) = 36"
    Thrown offset, i.e. vertical displacement of top of image from lens (h3) = ??
    Lens Centre Height (H) = h1+h2+h3

    Therefore

    h3 = L * tan(A) = 15"

    so

    H = 36+41.75+15 = 92.75 (so nearly 8' up)

    So given a 10' ceiling I need either a ceiling mount with more than 2' drop or a wall mount at about the 8' mark.

    Is this right? I now see why lens shift might be nice to have :suicide:

    Cheers
    Matt
     
  2. mattkhan

    mattkhan
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    some further searching (this site) has revealed some spreadsheets floating around that basically confirm the above. Working out whether a fixed lens PJ fits in your room is a fair amount of work :)

    Cheers
    Matt
     

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