[T-Bone]

We'll start new construction in several months and we'll have our theater area pre-wired for video/sound. Because we do not yet know the type of FP we'll use (they all have different throw distances), we do know that we want a 100" diagonal (~80" wide) screen.


So, what is the best approach for determining the FP distance before the theater is wired? I know FPs have different throw distances, and zoom factors. Do I use a combination of these two factors to determine distance?


Thanks...

 

[Marc Ye]

Room size determines what size sceen you'll use and therefore projector. Here's some general info that may help you out. According to CEDIA, Screen size (NTSC) is determined by 1/2 the diagonal and 30% of the seating distance. If you're using an NTSC/ HDTV picture, the guidline is 30%-50% of the seating distance. In addition, to be a little technical, seating distance from the screen should have an optimal vertical subtended angle of 15 degree's or more and the horizontal subtended angle should be 30 degree's or more. Hope this helps.

 

[T-Bone]

Thanks for the reply, but it seems like you gave data for seating distance (unless I misunderstood your post).


Our theater room is is large enough to support a 100" diagonal 16:9 screen (see attached jpeg). As you can see from the diagram, I initially positioned the FP at 18' (just a guess for the sake of creating the layout). The seating arrangement is flexible, but will probably be arranged like in the picture.


Sure, I can place the pre-wire from anywhere from 12' to 18'. So, how do I compute the FP distance for the pre-wire?


Thanks...

 

[Larry Fine]

T-Bone, you're asking quite a lot: "How do I choose projector distance without knowing which projector I'll be using?" How can anyone possibly give you a decent answer? In my opinion, you need to choose a projector first.


A future-proofing possibility would be to install a conduit along the centerline of the room, with an access box every one to two feet, long enough to cover all the possibilities, and blank-cover the unused openings.

 

[outlier2]

This is a difficult situation and one I am currently facing also. I have decided to try to at least narrow down my PJ choices to two or three likely ones. One is a short throw and two are longer throws. I will build for the short throw and put an access box that meets the specs for the two long throw options (conuduit runs through the long throw access). If I decide to go long throw then I will simply pull back my cables and drywall over the short opening. My rack will be at the back of the room, if yours is at the front, simply do the opposite.


Outlier

 

[T-Bone]

Larry, outlier2: guess it wont hurt to have several drops and conduit to give me the flexibility of going with a any FP.


I was hoping that the location could be derived mathematically using the range of throw values for a given FP, in conjunction with the zoom, such that I could pick a location, then use these two parameters to make the FP fit that location and provide the size picture I wanted. Oh well, guess not.


Thanks...

 

[usehername]

I stay off center when the throw is not known. I mount a ceiling box for the power on one side and the video cables on the other. About a foot off center for each. Plenty of slack with the wires.

 

[outlier2]

T-bone,


The problem is there are projectors with short enough throws compared to others that there won't be an overlap spot where you could set up either projector. If you are flexible with your screen size (I"m not) then you might get away with a single position and you can use zoom to try to get your screen size as close as possible.

 

[chirpie]

Here's a stupid idea (since I thought of it...).


Maybe just find the distance that'll snag you the majority of projectors... if 15 ft. is the magic number (I'm not saying it is, it's just an example) and that'll give you a pick of a higher percentage of the projectors out there, as opposed to 20 ft, go for that...


But then my experience with projectors is limited so there may be someone who comes in and says the choices are equal across the board and there is no magic number that'll encompass the majority...