How to Buy a Projector

What the best home theater projector has

• 1080p resolution. If you're on a tight budget, 720p projectors make an affordable, enjoyable alternative -- but ideally a home theater projector should offer native 1080p resolution so it's able to display images with perfect sharpness at larger screen sizes.

• Good brightness range. Measured in ANSI lumens, screen brightness refers to the light thrown out by the projector. More is usually better in situations with some ambient light, like a living room with windows or lamps. Also, the brighter the projector, the larger a screen it can project onto. Too much brightness in a dark home theater room, however, can lead to headaches and eye strain -- so being able to dial down the brightness when needed is important.

• Deep blacks. Dark blacks, and the ability to show details in dark areas of the image, are hallmarks of a quality projector and deliver the most cinematic viewing experience. This is most important if you have a home theater room that can be made very dark. In moderately lit spaces -- such as a den or family room -- the difference between a projector with top black levels and one that's only so-so in that respect becomes difficult to see.

• High contrast ratio. Contrast ratio refers to the difference between the darkest black and brightest white in a projected image. A high contrast ratio implies -- but doesn't always deliver -- deeper blacks. Differences among manufacturers in the measurement of the contrast ratio often render that particular specification meaningless -- but it's still worth taking note of.

• Accurate colors. The ideal is a home theater projector that delivers pre-set modes with colors that hit their mark perfectly -- or come close enough that only the most obsessed perfectionist will feel the need to do tweaking or to spring for a professional calibration. That said, projectors that aren't perfect out of the box but can be made that way with a little (or even a lot of) attention still deserve consideration.

• At least one HDMI input. More are better if you can get them. HDMI connections are all-digital, the preferred way to send high-definition signals from one piece of equipment to another. Furthermore, HDMI is compatible with HDCP (High-Bandwidth Digital Content Protection), a copy-protection scheme incorporated into Blu-ray disc placers and upscaling DVD players. An HDMI input is required to see images from those sources at their highest resolution and picture quality.

• A quiet fan. Projectors can put out a fair amount of noise while running in "Bright" mode or 3D. Most manufacturers promise sound levels of around 22 to 32 decibels, or somewhere between a quiet whisper and a hushed conversation -- but in actual practice, some projectors are noticeably (and annoyingly) louder than others.

Know before you go

Do I need an external sound system? In most cases, the answer is yes. Audio plays a big role in bringing the movie theater experience into the home. While many projectors have basic sound built-in, it's a far cry from the theater-like experience that even a basic surround-sound system can deliver. Creating a home theater system means assembling one yourself by buying a home theater receiver and home theater speakers. Other options include an all-in-one home theater system or a sound bar.

Do I need a projector screen? Again, for most the answer is yes. A white or light-colored wall can do in a pinch or for occasional viewing, but a projector screen -- included painted-on projector screens -- can help boost apparent performance by quite a bit. Some choices are covered in our report on projection screens.

How long to projector lamps last, and how much do they cost? Average lamp life in a home theater projector is between 2,000 and 4,000 hours, and replacement lamps are not cheap. Most cost upward of $250.

Is my room big enough for a projector? Most projectors are capable of throwing an image of more than 100 inches, measured diagonally. That means that most viewers will need to sit at least 10 feet away to get the best view -- although some now suggest sitting closer when watching a 3D projector. In any event, if you're working with a very small room, a projector might not be the best choice.

Where will you put the projector? Any projector can be placed straight back from the screen, either on a platform or a ceiling mount. The projector's zoom capability will determine just how far back it can be placed. Placement flexibility is also increased if the projector has lens shift capability, which lets you move the projected image vertically or horizontally.

Projector technologies: DLP, LCD and LCoS

When you start shopping for a projector, you'll immediately notice that there are three main projector technologies on the market: digital light processing (DLP) liquid crystal display (LCD) and liquid crystal on silicon (LCoS).

Historically DLP projectors boasted better contrast and black levels, while LCD projectors had better color saturation with less fan noise and lower operating temperatures. Because of improvements in both technologies, those differences have almost disappeared. However LCD projectors still have a brightness advantage, and DLP projectors tend to be a bit smaller because the technology takes up less space.

These common projector types have Achilles heels, too. When using a DLP projector, a small percentage of viewers will spot occasional flashes of color known as the rainbow effect. This is caused by the DLP projector's rapidly spinning color wheel. LCD projectors don't create a rainbow effect, but you can -- on lesser models -- see cross-hatching on the projection screen as if you were viewing it through a screen door. Blur or softening can also be a problem with fast-moving objects on a LCD projector. In general, DLP projectors handle fast motion better.

LCoS suffers from few of the drawbacks of other projection technologies. There's no color wheel, so rainbow effect is not an issue; neither is screen-door effect or excessive motion blur. In general, LCoS projectors are well-regarded for deep black tones and good color accuracy. However, LCoS chips are expensive and difficult to produce, limiting them to more expensive home theater projectors.

What's to come

At the 2013 Consumer Electronics Show, LG announced its new Hecto laser projector. This is a DLP projector that does away with a traditional lamp, replacing it with a laser light source. Pricing for the LG Hecto laser projector was announced this spring, at around $9,000. That initial pain is mitigated -- a little -- by the fact that the laser is expected to last five times longer than a standard projector lamp.

The LG Hecto ships and must be used with a proprietary 100-inch screen. With a fixed throw distance of less than two feet, the projector is designed to sit essentially under the screen, on a credenza, home-entertainment console, or a similar piece of furniture. The LG Hecto was yet to ship at the time this report was prepared, but CNET looks at a near production version, and has a mixed take on it. One interesting finding is that the LG Hecto laser projector has more in common with a standard flat-panel HDTV or a rear projection TV than it does with a standard video project. That includes an image that stands up well even under normal room lighting.