Today's home theater enthusiasts are presented primarily with two competing front projection choices: LCD and DLP. Although both technologies are smaller and lighter than their CRT projector elders, their similarities end there. As with any set of competing technologies, there are compelling reasons to select one over the other, depending on your viewing preferences, installation requirements and budget. Understanding the nuanced differences between these projector types will help you make an educated decision when it comes time to upgrade.
Contained inside the compact outer casing of liquid crystal display and Digital Light Processing projectors are two very different light engines. LCD technology uses a series of colored mirrors, dividing the light beam into the red, blue and green primaries. From there, the separated light beams pass through a dedicated prism. The individual crystals within the prism panel turn on and off, based on the information provided by the video processor. The degree to which the crystals twist dictates the gradation of each color. When this complex information is recombined at the lens, you see the stunning images that result. DLP either shines a single light though a spinning color wheel or shines separate colored lights. The light or lights then strike a single, small chip containing millions of tiny mirrors. The degree of tilt applied to each mirror dictates the grayscale, forming individual colors. Three-chip DLPs used in high-end or commercial applications shine the light off of three DLP chips, each one representing a primary color. This technology produces more accurate colors and higher brightness than single-chip models.
Overall picture quality on any display is defined by color and grayscale accuracy, contrast ratio and sharpness. The degree to which each technology produces a "better" image is a function of the quality of video processing and the ability of the device to be tweaked and calibrated. Grays and whites should be devoid of color tinge, and colors should be punchy and accurate, though not oversaturated. DLP color accuracy has improved over the years with the advent of technologies used to overcome the orange cast that previously plagued it. LCD projectors often appear brighter, but this is adjustable between the two technologies. The inherently more accurate color and out-of-the-box brightness advantage offered by LCD causes many to ascribe the image as sharper and more detailed. Three-chip DLP bridges this gap but at a much higher price.
Maintenance and Cost of Ownership
Although some projectors offer a no-filter design, many LCD and DLP models still have filters that require cleaning or replacement every so often. These are most often found in commercial environments such as bars and restaurants. Bulb replacement is a factor in both technologies, save for LED LCD projectors that are lamp-free but very costly. Expect to pay around $200 to $400 for a replacement lamp, with a 2,000 to 4,000-hour life expectancy. If you use your projector at night or primarily for event viewing such as a movie or major sporting event, you'll be replacing a lamp about once a year on average. Neither produces a prodigious amount of heat, but you need to keep the fans and vents unblocked to avoid overheating.
Either technology offers the ability to be mounted off-center, a necessary feature in many living rooms that double as home theaters. However, this lens shift comes at the price or resolution and clarity. If you're an avid videophile, any degradation of picture quality may be of concern, but casual viewers might not notice the difference. With any projector, you'll also need a screen or specific type of wall coating to maximize image quality. Some screens offer glass beads or other technologies to enhance brightness. Used with special films and curvatures, some of these screens allow use in full light like a conventional flat panel. Recognize that any projector other than the largest and most expensive require minimal room lighting to look their best, often precluding daytime viewing. If the unit is ceiling-mounted, you'll need an electrician to install an outlet close to the projector's mounting bracket.
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