Read the First Part of the Article: How-to: Install a Front Projector & Screen.
So with our projection screen mounted and waiting for video, it’s almost time to mount our projector. But before we do (you guessed it) there are a few tasks we have to accomplish first, one of them is determining the screens centerline, centering a projector is critical for proper optical alignment. I’ve seen and heard dozens of methods for determining true center in relation to a fixed object but none of them seem as easy or ultimately accurate (no, using a tape measure isn’t accurate, that assumes your room is perfectly symmetrical, it’s not) as the one I use.
For this part you’ll need an assistant, a ladder, the nylon string and pencil I mentioned previously. Pull off a long piece of the string and tie a knot at one end, have your assistant hold that knot in their hand and hold it up to one end of the screen frame (fig. A - at the top of the screen). Now, pull off enough string to make it back far enough so that you’re into the projector manufacturers recommended throw distance (Fig. P) for your particular screen size. (Note: the throw distance can either be found in the owner’s manual or on-line by searching for brand/model + throw distance).
Once you’re certain you’re back far enough into the recommended throw distance (preferably ¾ into it), tie the string around the pencil and pull the string tight. Once you’ve done so point the pencil toward the ceiling and make a light mark in an arc motion. Have your assistant move to the other side of the screen (Fig. B) with the string and then make a second, complimentary mark from the other side. As long as all the variables were minimized, i.e. the assistant held the string at the same position on each side of the screen and you pulled the string tight, you’ll have a perfect center mark.
Now a bit about cabling, of course you’ll want to run a HDMI cable from your equipment to the projector, and for good measure I’d recommend a component cable as well but go ahead and run a CAT5/6 cable as well. You may use the CAT5 cable as a screen trigger, you may use it as an IR emitter, you may never use it at all, but there is no time like the present to build in a little future-proofing. Now, since we’re on the subject of cables, we need to talk about getting power to the projector.
Electricity isn’t something to play around with and neither is the longevity of your projector. As such I recommend that you hire an electrician to pull a supply cable to your projectors location. I do not recommend running extension cables across your attic or sub-floor as they (1) aren’t intended for permanent use and (2) might not deliver enough current to the projector. That said we’re all adults here and should be able to decipher the real-world implications of using an extension cable to power your projector.
Ok with cabling issues out of the way it’s time to talk about what type of mount we’ll use.
I’m a proponent of universal mounts over model specific mounts (in most cases) but not for the reasons you may think. Yes, if you have a heavy projector, an unusual projector, and or your model specific mount is significantly cheaper than a universal mount, by all means use one. But there’s something you can do with universal mounts that you can’t do with model specific mounts. That something is shifting the projector around slightly whereas otherwise you’d be “stuck” in one spot praying you got your calculations right
The specific type of mount I’m referring to is often called a spider mount (it will have 3 or 4 arms) and its arms can be rotated clockwise or counter-clockwise to give you a little extra push left or right. I’m telling you from experience this small amount of play can be invaluable in a crunch. Ok now, we’re ready to attach the mount to the projector and likewise attach the mount to the ceiling but there’s one last piece of business to consider, the height of the projector in relation to the screen.
Again, I’m working on the assumption that your projector doesn’t have vertical or horizontal lens-shit, (if it does skip down to the next passage) we need to factor in the projectors vertical off-set, or in other less technical terms where the lens needs to sit in relation to the top of the screen. This is an important measurement (again often found in the owner’s manual) because if it’s off even just a little, it will cause the image to keystone and trust me that’s not something you want to happen.
In a nutshell, if the top of your lens is 14” above the top of the screen and your specification calls for a flat or zero off-set, you’ll want to drop the mount/projector down roughly 14” (add or subtract to that number for the actual drop of the lens to the top of the projector case). Basically you just want to add or subtract extension until you’re within the recommended vertical off-set. A few words about extensions, Home Depot can custom cut and thread pipe extensions to fit your projector mount. But remember the golden rule, measure twice, cut once. Or in other words, you don’t want to make a second trip to Home Depot for a slightly longer or shorter extension.
Remember when we talked about not mounting the screen any higher than necessary? This is another good reason for that. It’s relatively easy to add an extension pipe to your mount but what do you do when you (1) don’t have the luxury of lens-shit and (2) already have the screen higher than you can push the projector? The unfortunate answer is to start over or switch gear.
Ok, screen in place, mount in position and vertical off-set factored in, you my friend are ready to attach your mount to the ceiling. I recommend using heavy “anchor” bolts or galvanized decking screws. It’s not the weight of the projector that really matters (these days anyway) but the mounting, maintenance, and eventual adjusting can stress the screws over time. Trust me, just use a relatively heavy anchor bolt or decking screw and sleep well knowing your projector is securely attached to the ceiling.
Now it’s time to mount the projector, with your assistant go ahead and put it up into position, bolt it down (loosely) and plug the cables up. Once that’s done you’ll want to turn the projector on and make sure the image is squared with the screen. As long as you minded your P’s and Q’s and followed the manufacturers distance recommendations you should be fine. If things are a bit askew not to worry, loosen the mount arms a tad and nudge the image into position. If you need a little extra shift to the left or right you may have turn the arms around 180 degrees.
Once that’s complete tighten everything else down and reap the rewards of your hard work. I’ve tried to present this information, in the simplest manner possible, but of course specific projector and screen combos can present unique problems. As always, I will be happy to answers any questions in the comments I can. By the way, don’t forget the last item in my list of recommended tools and materials.