Jun
13
How-to: Install a Front Projector & Screen
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As far as I’m concerned nothing says home theater like a front projection system, there’s just something about a 2-piece system that really captures the magic of going to the movies. The beautiful thing about front projection is that even in this day a 50” Kuro plasma’s and a 40”- 1080p LCD’s for under a grand, front projection still provides the best bang for the buck in screen size, and with fuel prices continuing to climb that trend will likely continue.
As much as everyone around here loves projectors, it’s obvious that they aren’t for everyone. There are multiple reasons for this but two of the biggest are the need for a relatively dark environment and the fact that installing a projector really isn’t seen as a do-it-yourself project. Well, I can’t help with the dark room but I assure you that if you’re even moderately handy around the house, you can install your own front projector and screen.
First things first, I like to start with the screen. The screen should be your anchor, not the projector. Think of it this way, the screen is what you’ll actually be looking at, so it’s important to have it where you want it in the room and then worry about how to get the projector where it belongs. I fully acknowledge that there are other schools of thought on which comes first (the projector or the screen) but after having installed an upwards of 125 front projection systems over the years, I have come to know, love and embrace the path of screen first.
So with that we need to establish the proper height to mount the screen at. Even though we’re installing the screen first, take a quick look over your shoulder at the area where you’ll mount the projector and look for any obstructions. If you see a heating and air vent, smoke detector, ceiling fan or anything else that might be in the path of the projector or mount, you’ll need to factor that in. i.e. if the true center of your room is offset by 2” to the right due to an obstruction, you’ll want to shift your screen over to the right by 2”.
Jun
13
How-to: Install a Front Projector & Screen (Part 2)
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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.
Feb
28
Screen Gain 101
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If you’re new to the front-projection world, at some point in your research, shopping or browsing you’ll stumble on the term “screen gain”. You’ll want to know what this is and how it applies to different rooms and projectors before proceeding down the front-projection path to home theater nirvana. Screen gain is the measure of how reflective the screen material is, or in the broader sense, how much light the screen reflects back into the room and ultimately to your eyes.
Typical screens are rated at gains from 1.0 (neutral gain) to 1.2, 1.3 and beyond. There are even some negative gain screens designated as 0.8 and alike. Generally speaking however all you have to remember is that a 1.3 gain screen should appear brighter than a 1.0 gain screen, at least from the same manufacturer. Although rare there are cases where one manufacturers 1.0 gain screen could appear brighter than another’s 1.2.
I generally advise my clients to stay away from the ultra high-gain screens if they have the ability to control the light in the room, i.e. make it completely dark. Typically the low-gain screens present less off-axis viewing irregularities and in many cases just plain look better than their high-gain counterparts, when paired with a bright enough projector. Of course if you can’t control the light in your room at all times of the day, a high-gain and or high-contrast gray screen may be just what the doctor ordered.
Feb
26
Digital Light Processing (DLP)
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In order to discuss the different display technologies effectively (at a later date) we’ll need to define some of them upfront. I could have started with LCD, plasma, D-ILA, SXRD or any number of others but I wanted to start with DLP (Digital Light Processing) as its one of the most common front projection technologies in use and well, front projection is just plain cool. DLP was developed by Dr. Larry Hornbeck at Texas Instruments in the late eighties but believe it or not front-projection wasn’t one of the first implementations. It (DLP) was actually used to fuse red dyes (text and images) onto airlines tickets.
DLP uses millions of moving micro-mirrors to create the images we see on-screen, the mirrors are fixed to a chip called a Digital Micromirror Device (DMD) which is illuminated by the projectors lamp (gross oversimplification). The technology is known for its accurate colors, sharp images and often better than average contrast ratio.
DLP’s create color by focusing the light path through a color-wheel; multiple “colors” are projected by varying the speed of the color wheel. Early DLP’s were prone to smear colors (known as rainbow effect) due to the slow speed of color-wheel but this was all but eliminated in recent models by higher-speed, multi-segmented color wheels.
3-chip DLP projectors eliminate the color smearing problem altogether with the use of one DMD per primary color, i.e. red, green and blue. 3-chip DLP’s are quite expensive when compared to their single-chip counterparts but are generally perceived as superior in all regards.