Home Theater Add-Ons

Sometimes, solving a problem is as simple as knowing the right tool to use.

Gustave Flaubert was a realist and a perfectionist. No wonder he came up with this gem: "Happiness is a monstrosity! Punished are those who seek it." This might well be the mantra of anyone who seeks to put together a high-performance home theater. Unless you start with a set of blueprints and a lot of expertise, you're going to run into a few punishing problems on your way to home theater happiness. Fortunately, Wilkinson's First Law of Home Theater (mine, not Video Technical Editor Scott's) states: "There ain't no problem that can't be solved by throwing large amounts of money at it."

Only as Good as You Can Throw It
If the home theater of your dreams involves a front projector, certain problems may make you wish you'd paid more attention in math class. Like that archaic analog device called the slide projector, a front-projection television's job is to throw an image on a screen. It seems seductively simple—especially now that DLP- and LCD-based units keep getting smaller. All it takes is basic geometry, right? For a large image, move the projector away from the screen; for a small one, bring the projector closer.

Although this is indeed the case with projectors with a fixed-focal-length lens (something not typically found on projectors designed for home theaters), the situation isn't quite as benign as it seems. With a fixed-length lens, there's only one distance from the screen, called the throw distance, where you can place the projector in order to create the size image you desire (or require). Unless you're willing to rearrange your living room or move walls, the right spot for the projector is, more often than not, the wrong spot for convenient living in the room.

Fortunately, most home theater projectors are equipped with variable-focal-length zoom lenses that provide a range of throw distances from which you can project the same image. (With a variable-zoom lens, you can change the picture's size without moving the projector.) Even with this advantage, there are still some installations where the projector will need to be closer to or further away from the screen than the lens' adjustability (and focus) will allow for.

The easiest solution is to find another projector with a range of throw distances. But, what if you have your heart set on a particular non-conforming projector? More problematic is deciding what to do should a remodel or a move to another home suddenly cause your projector's capabilities to throw you for a loop. Buying a new projector and/or screen isn't a cheap—or often an acceptable—fix.

One solution is to perform the equivalent of cataract surgery on your projector. Navitar's Buhl replacement projector lenses are designed so that you (or, preferably, a service technician) can remove the original lens and replace it with a high-quality lens with the correct optical characteristics for your room. (The procedure adds a new dimension to the term "operating theater.") Unfortunately, not every projector's lens can be replaced. Even if yours can be, such a dramatic change is likely to void a new projector's warranty, and you may need to reverse the procedure should you move the projector's location in the future.

Navitar has another solution—adding a conversion lens. That's akin to placing a set of eyeglasses (a monocle, actually) in front of your projector. Since it's a true add-on rather than a replacement, you can easily remove the lens at any time and return the projector to its original optical specs. Furthermore, you can install the lens yourself in the privacy of your own home.

Navitar's four ScreenStar conversion lens models work with a wide variety of DLP, LCOS, and LCD projectors (both 4:3 and 16:9) and can change a picture size or throw distance by 20 to 50 percent. Surprisingly hefty and extremely well built, the lens sits on a stabilizing leg in front of your projector's standard lens. The stabilizing leg has predrilled holes for semi-permanent mounting. You can also use it with an extension arm attached to a projector mounting plate, which is available from companies such as Chief and Premier. Navitar also offers a table stand that holds the lens at adjustable heights and angles, making it compatible with many more projector designs.

The wide-angle converters increase the picture size (50 percent with the 0.65X SSW065 and 25 percent with the 0.8X SSW08) from the same throw distance, and they also allow you to move the projector closer to the screen (33 percent with the SSW065 and 20 percent with the SSW08) while retaining the same image size. The long-throw telephoto conversion lenses do the opposite—they reduce the picture size (33 percent with the 1.50X SST150 and 17 percent with the 1.20X SST120) without moving the projector, and they let you maintain the image size from a projector located further from the screen (50 percent with the SST150 and 20 percent with the SST120).

The quality of Navitar's all-glass, multicoated Buhl conversion lenses is exceptional. The projected image is a nearly perfect copy of the original image, with no visible geometric distortion or vignetting. The image is sharp and bright all the way to the corners. Navitar estimates that you might lose anywhere from 5 percent (with the smaller lenses) to as much as 15 percent (with the larger lenses) of the picture's brightness; but, when demonstrated with my Barco Cine VERSUM 60 projector, it was difficult to perceive any difference in brightness at all.

When it comes to pricing, Navitar makes things even simpler. The big lenses (the SSW065 and SST150) are $1,497, and the smaller models (the SSW08 and SST120) cost $990.

Raise It to Get Down
Your projector may not be the only problem-plagued component in your home theater system. Subwoofers typically suffer (not in silence, unfortunately) from the interaction of sound waves being radiated by the sub itself and those reflected off of parallel walls in a room. The resulting room modes cause an uneven distribution of sound throughout the room. While you can minimize the effects in the room's horizontal plane by shifting the subwoofer's location, there's still the problem of the vertical room mode. The 8-foot ceiling height of most rooms generates a room mode that sticks an acoustic dagger in the heart of most subwoofers at around 70 hertz.

Acoustic Sciences Corporation (ASC), a company that's built their reputation on acoustic problem solving (you've probably heard of ASC's Tube Trap), offers a sophisticated but simple-to-implement solution to the vertical-room-mode conundrum called the ASC SubTrap.

From the outside, the SubTrap looks like a black, fabric-covered box (custom colors are available) that you might mistake for a subwoofer. Place your subwoofer on top of the SubTrap, and, in many rooms, you'll hear a more uniform bass output that's tighter, stronger, and more defined. It's that simple: no cords, no plugs, not even any tools other than something to help you open the shipping carton.

The SubTrap works in three ways. First, it raises the subwoofer up and out of the vertical room mode's low-pressure zone. Second, it functions as a bass trap in the sub's original location, dampening mode buildup. Finally, the SubTrap acts as a floating platform, mechanically preventing the subwoofer's vibrations from transferring to the floor and the rest of the house.

For most subwoofer configurations, ASC recommends their $438 18-inch SubTrap, which can support up to 250 pounds. Fifteen- and 22-inch versions are also available for subwoofers with smaller or larger driver or cabinet sizes.

Navitar, Inc.
200 Commerce Dr.
Rochester, NY 14623
(800) 828-6778
www.navitar.com

Acoustic Sciences Corporation
4275 West 5th Ave.
Eugene, OR 97402
(800) ASC-TUBE
www.asc-home-theater.com
www.tubetrap.com

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