It might seem elementary to talk about projector mounting, but the fact that there are so many options available on the market today justifies an understanding of what sets different mounts apart, and how your mounting location can be an important determining factor in which projector mount you need.
The first obvious step in ascertaining your mount type is to decide if you are front projecting or rear projecting for a new installation. In some cases, a custom enclosure has to be built for a rear projection system because the required depth is not available for the image to be as large as it needs to be. This involves some engineering as mirrors have to be used to bounce the image around until it gets large enough to fill the screen. Fortunately, the need for this kind of elaborate construction has become a bit rarer these days, but it does still exist. I have a church client who is using 4000-lumen ultra-short-throw laser projectors to replace medium throw lamp projectors for a rear projection solution. It's not stellar, but it does produce a better image than the older units. The projectors are not mounted, but rather sit on the floor beneath each screen, which takes up far less space and enables more of the rooms behind the screens to be utilized for storage, their original intent.
If you're front projecting, there are more decisions to make, such as included security hardware, roll and tilt control, ceiling or wall mount, and wheter you are using a long/medium throw, short throw or ultra-short-throw projector. The wall mount for a UST projector is different than for a medium- or long-throw projector and includes certain adjustments that are specific to UST projectors. Anyone who's installed a UST can tell you that any small adjustment on the projector mount makes a huge difference in the geometry of the image displayed.
If you imagine your projector as a really large TV installed in a public space, you begin to understand why having certain features in your projector mount are important. For example, if you have a low ceiling and you plan on mounting from the ceiling, security features could become more important to make it harder for someone to steal your projector(s). If you are needing to project onto the floor, having tilt and roll correction features may have a high priority. How about hanging from a pipe or truss? If your projector is inside a classroom and you need a digital whiteboard, knowing the correct mount to use for an ultra short throw projector will save you a ton of headaches.
Here are a couple of pointers to help you figure out where to mount your projectors. First, keystone correction (vertical or horizontal) included in a projector can be a really helpful tool in getting your image to align with your screen. However, it can also mean losing up to 15% of your image brightness, which is significant. It is far better to ensure that your projector and screen are positioned as well as possible to avoid keystoning.
Similarly, if your projector has lens shift capabilities, this can help get around alignment issues, but again, it may sacrifice brightness and that is something to avoid when you invest in a quality projector. I would recommend that prior to hanging a projector, find the vertical "offset" number specific to your projector. This is a measurement, provided by the manufacturer, that describes the ideal distance between the top of the screen and the center of your projection lens. This number is provided to help you more closely identify where your projector needs to be mounted vertically in relation to your screen. For horizontal alignment, you will want to make sure that your lens is located as close to the center of your screen as possible so you can hopefully avoid using any horizontal lens shift.
Experienced installers know instinctively what's wrong when projector is clearly out of alignment, but even if you're a newbie it's easy to figure out. As shown in the image below, if the top and bottom of your image are not perfectly parallel to one another, it's a horizontal alignment issue. Whichever side (left or right) appears taller is the side that you need to rotate the projector horizontally towards. If the left/right sides are not parallel, then the vertical alignment is off, which means the projector needs to be raised or lowered or its tilt corrected.
You may be planning an installation where you know due to room limitations that you will not be able to properly align your projector to your screen and must use some form of built-in correction technologies—either the keystone or lens-shift controls, or some other form of geometric correction. If this is the case, and you are looking at getting new projectors, you will want to account for that loss of up to 15% brightness and get brighter projectors. If you already have projectors in place, then there is not much you can do, unfortunately, to get this brightness back.
Another key element people should account for but sometimes skip over until it's time to install is having a solid plan for running signal and power to the mounting location. If you have a building with no crawl space between the ceiling and roof, this nearly always means a surface run for cabling. Do you need to hide that cabling or can it be exposed? Is there a local code that requires cabling to be inside conduit of some kind?
Of course, if you want to set yourself up to succeed, and that means knowing all the critical information, such as: throw distance; screen size; offset; where your ideal projector mounting location is (taking into account horizontal and vertical alignment); whether you are mounting to pipe/truss, a ceiling or a wall; whether your ceiling is flat or pitched; how you will be getting power and signal to the projector(s), etc. There are many important factors to consider in a projection system, and while the mounting location and mount type may seem like a small piece in the overall system, it nevertheless is an important piece.
Not all mounts are designed or built the same. There are the super cheap mounts that might do the job of attaching your projector to a wall or ceiling, but perhaps won't have the fine adjustments that let you get your image perfectly aligned with your screen. Or worse, the materials are so cheap that it fails and drops your projector onto a worshiper. Maybe you want to run your power and signal cables down the inside of the mounting pole, but your mount doesn't allow for cables to exit from the pipe cleanly and it necessitates you running cables down the outside of the pole. Or you may find the money you saved on the mount is less than the expense of time it takes you to actually install a product that is not intuitive or easy to work with.
There are many considerations when it comes to a mount and there are no shortcuts for figuring out what is going to work right for your specific situation unless you choose to work with a professional. Remember, there is no "one size fits all" option in A/V, and it's always best to get the right system for your specific needs. Figuring that out takes time and diligence. If you're not experienced or equipped to do that yourself, my advice—as always—is to bring in someone who is.
Tim Adams is president and chief systems designer for Timato Systems, an audio/video integration company specializing in servicing the sound, lighting, video, projection and live-streaming needs of churches and other houses of worship. He can be reached at firstname.lastname@example.org.