Basement Theater problem?

Discussion in 'Home Theater Projects' started by John Swarce, Mar 30, 2003.

  1. John Swarce

    John Swarce Second Unit

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    Hi, folks. I am in the planning stages of a dedicated home theater in my basement. The room is unfinished (studs only), approximately 15'W X 22'D. The height is currently 7'6" floor to ceiling. I plan to put a drop ceiling in, bringing the height to 7'3". There is a 6" support beam that bisects the room (essentially two 11' rooms could be made). Here's my problem/question.

    I want to ceiling mount an FP to project onto a 90"-100" diagonal screen. Looking at the throw distance of my projector of choice (Panny 300), I would have to mount it about 12' back. This would put the projector behind the support beam, hanging down about 6'5" from the floor(to clear the beam). Seating would be about 11' to about 14' (2 rows of sofas, second row on a 6" riser). Will this pose a problem with viewing issues for the second row? Should the projector be mounted forward of the beam? I know it vents it's heat to the back, so it would need some space in front of the beam.

    Should I just dump the ceiling mount idea and go with a floor mount? A floor mount would present some wiring issues, I think. I wish I could lose the beam, but it does support the rest of the house! Moving the theater to another part of the basement would mean a smaller width (11'), below the bedrooms (it's a ranch style house), or too close to the heating system.

    Nothing is cast in stone yet, as the room is a "blank canvas". Any help/advice would be much appreciated!
     
  2. John Swarce

    John Swarce Second Unit

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    Anyone?? Bueller?
     
  3. MikeWh

    MikeWh Second Unit

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    John,

    Bueller here. I'm not an FP person, but seeing as nobody else has replied yet, I thought I'd add my 2 cents.

    From what I understand, projectors have a stated height that the center of the lens should be relative to the bottom of the screen (or top of the screen, in a ceiling mount config). I couldn't find a manual on panasonic's site for a 300. Since you apparently know the throw, I'm assuming you have access to the manual. The 390 manual lists the following:

    80" wide image--
    proj to screen: 10'6" to 15'5"
    dist. from lens center to (top) edge of screen: 5-1/8" to 2'

    100" wide image--
    proj to screen: 13'6" to 19'4"
    center-to-top/screen distance: 6-5/16" to 2'5-29/32"

    First, note that the 100" picture requires a longer distance-to-screen that the 12' you've proposed, so make sure you know the right numbers for the 300 and settle on a screen size.

    Next, you'll need to figure out where you want the top of the screen to be first. Then you can do the calculations.

    Just looking at the above numbers and taking a guess as to your proposed screen height, I don't think you'll have a problem clearing the 10" (or-so) beam. Figure all that out first, THEN take a look at what the height would be relative to the people in the back row.


    OK-- FP folks.... does this sound right???!?
     
  4. John Swarce

    John Swarce Second Unit

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    Thanks for responding, Mike. For a while, I thought I was the only one on this forum! [​IMG]

    The brochure I downloaded from the Panasonic website was available here

    The specs on the 300 state for a 100" image you need a minimum of 10.2' to a maximum of 12.1'. This puts the projector smack dab in the middle of the ol' beam. 1.5 X the screen width of 8.2 feet would put the seating at 12'. I suppose I could mount it in front of the beam, but I was concerned about airflow for the fan. I couldn't find anything about the height of the projector to the top of the screen on their site or in the PDF brochure.

    My thoughts were on the view from the back as far as seeing the entire screen. Too high and the projector may interfere with the top of the screen...too low and the heads of the people in the first row would block the bottom of the screen. I guess I will have to do some calculations based on these numbers.

    Anyone else want to chime in?
     
  5. Neil Joseph

    Neil Joseph Lead Actor

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    Let's start with some calculations....

    A 100" 16x9 diagonal screen is 49" x 87". Your ceiling height (after drop) would be 7'3". Your projector's lens will be at a height of 6'5" according to your measurements. You will need to mount the screen at the maximum possible height in that room which would be ~7ft + a 3" border which would bring the assembly at 7'3". You will then need to tilt the projector slightly upwards and you may need slight keystone correction or lends shift if you can accomodate it. This will place the bottom of the screen at 35" (not including blackout borders).

    You will need to either mount the centre speaker below the screen and tilt up, or mount it above the screen from a ceiling or wall mount and tilt down.

    The first row of seating @ 11' will not have any viewing problems.

    Your second row @ 14' will be ~1' behind the back of the projector with the front of the projector being 12' from the screen. While seated, your eye level is around 47-48" from the ground so your second row of seating which is 6" above the first row, will have an eye level of around 53"-54". Considering the L300U will be 1ft in front of the second row which is at an eye level of 54", this will not pose a physical barrier for the viewer looking at the screen. However, the unit will be mounted very close to the second row viewers so I hope that it's fan level is quiet.

    Also, you WILL need to stagger the first and second row of seating in order for the person behind to see between the two people in front.

    Hope this helps a little.
     
  6. NathanH

    NathanH Stunt Coordinator

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    I'm looking at the Panny / X1 and have similar issues with a soffit running through the middle of my room about 17' from the screen at the rear. If I select the Panny, it would be placed in front of my soffit, so it is a non-issue. However, if I select the Infocus X1, I will need to place it on the soffit, in which case I will just have seating directly underneath to avoid any bumped heads. (That is an EXPENSIVE bruise!)

    This thread helped me out too folks!

    Thanks!
     
  7. John Swarce

    John Swarce Second Unit

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    Neil:

    Thank you very much for the calculations. I have read that the Panny 300 is very quiet, so noise level should not be too much of a problem.

    Does the need to stagger the rows result from the use of a 6" riser as opposed to something a bit higher? I didn't think I could get away with anything higher than 6" without people ducking to sit down in the second row! My thoughts were to have 2 rows of sofas, but the front row could be recliners (BTW, the wife suggested that the first row have swivel chairs...because "how are you going to talk to people in the second row if you aren't facing them?" [​IMG] )
     
  8. Neil Joseph

    Neil Joseph Lead Actor

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    You will need to stagger because the bottom of your screen is low enough so that the person in the front row is blocking the view of the person in the second row. I don't think it will be avoidable unless you stagger.

    As a side note, I had the exact opposite issues in my current room with its 13' ceiling which was so high that even with a 2' mounting pole/bracket, the projector was still very high up so I had to raise the height of the screen very high as well to avoid too much keystone correction.
     
  9. TimForman

    TimForman Supporting Actor

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  10. Adam_Bailey

    Adam_Bailey Extra

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    Neil,

    What do you mean by, "too much keystone correction"?

    I unfortunately had to mount mine lower then I wanted, on the ceiling inside a window seat in order for it to project big enough to fill my whole screen. I have to have the projector tilted up quite a bit, which caused a fairly significant trapazoid that I was able to correct using the keystone stuff.
     
  11. Tommy_C

    Tommy_C Stunt Coordinator

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    Your setup sounds very similar to mine. I have a room that is 12x23 and had a beam going across the center. I used an Infocus LS 110 for my projector and 110" screen. If you visit my site you will see the pictures and the beam. I did the drop celling about 4" and used the beam in my design and pillars. I was limited as far as distance back by my cable I bought. I would say stay back on your range so you can utilize all your zoom to fill the screen. I wish I was back about one foot as I have just a wee touch of screen not utilized and zoomed out as far as she goes. Look through my site and email me if you have specific questions. Good luck.

    TC
     
  12. Jeff Bamberger

    Jeff Bamberger Second Unit

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    You could always create another soffit behind the beam and mount the projector on that. This would also allow you to run wires right to the projector. In addition, it may allow you to create some form of hush box around the projector which would quiet the fan (but with need to create negative air flow to pull the heat out).

    I have seen all kinds of mount/hush boxes for full size CRT projectors, so it can work with anything.

    Also, as in the comments above, once you start to build, pay close attention to center channel placement with respect to the second row. The last thing you want is for front seating to block the center channel.
     

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