When it comes to televisions, thin is in

If you think that plasma is something vented from an alien spacecraft, or that LCD stands for "long cotton drawers," you need to brush up on your television terms.

Welcome to the world of thin, flat-screen TVs ... and all the glories and hassles of this brave new world.

Liquid crystal display and plasma are the two types of televisions that people think of when talking about thin, flat-screen TVs.

Because LCD and plasma screens are flat and thin, they have become a home designer's dream. Placed on a table or credenza, they take up less room than old-fashioned TVs. Mounted on a wall, they have no footprint at all — leaving more living space.

Plasma dominates the thin-screen market in the 42-inch-and-above category, while LCD is the technology of choice in the 32-inch-and-below range. There are LCDs 40 inches wide and larger and plasmas as small as 37 inches, but plasmas tend to remain expensive even as they get smaller, and LCDs often become more expensive than plasma at the same sizes. That cutoff line is getting fuzzier, however.

The average price for plasma and LCD TVs dropped considerably last year, and some analysts predict the same for this year, Business Week reported.

If you are considering purchasing a plasma or LCD TV, here are a few things you need to know.

Call in the Mounties

It takes a lot more than a wall anchor and a screwdriver to mount any TV on a wall. Pioneer's 50-inch plasma display, for instance, weighs 83 pounds, and Sharp's 32-inch LCD weighs 28 pounds without its speakers.

Both need mounting brackets designed to bear those weights. Basic mounts cost from $75 to $125. They are designed to be secured to the studs behind the wall rather than into the drywall for better stability.

Because plasmas are heavier and often more fragile than LCDs, many experts recommend professional installation. Mounting a smaller LCD could be a do-it-yourself project for a confident homeowner.

Please take the stand

Both plasma and LCD televisions can be placed on a table or in an entertainment center just like old-fashioned cathode-ray tubes. The monitors usually come with pedestals.

Because they are thinner, they need to be placed closer to the front of an old style, deep entertainment center so they can be seen by viewers on the periphery of the room. This could lead to problems with balance if the stand is wobbly.

Another problem with using an older entertainment center is that the openings are nearly square, not rectangular like the new widescreen TVs. That will leave a lot of headroom.

Frame it

Thin-, flat-screen TVs can be recess-mounted — set back into a hole in a wall so that the screen is flush with the wall. The result is that the TV looks like it could be framed artwork.

However, a flush mount demands consideration on how the TV's heat buildup will be vented. Some manufacturers recommend 3 inches of space above and behind a flush-mounted plasma.

Installers can increase ventilation by hiding vents behind the edge of a picture frame. Also, forced-air ventilation can be used.

LCD monitors typically create only about one-third of the heat that plasmas do.

You keep me hanging on

There are other mounting options that are less attractive but might be more functional.

Tilt wall mounts are used when the monitor is placed higher than the viewer's eye level. The screen tilts down to increase the viewing angle, which is about 160 degrees for plasma and 170 for LCD.

Articulating wall mounts have a swivel arm that folds up. When not in use, the TV appears to be flush-mounted. When the television is in use and needs to be turned toward the viewer, the mount moves the TV away from the wall and angles the monitor.

A hot topic

Before mounting a screen above a fireplace, consider the heat. A working plasma TV should not be exposed to more than 90 degrees of heat for an extended period of time because the cooling system must work too hard to keep it cool, shortening the television's lifespan. The TV can be allowed to get warmer than 90 degrees if it is not turned on, but that defeats the purpose of having it mounted there.

Installers need to consider ventilation behind and above the TV if it is flush-mounted. If there is a chimney hidden behind the wall, there may not be room for ventilation.

Make a sound decision

Most plasma displays are TV monitors, meaning that they do not have tuners or an audio system built in. Some LCD displays have either or both.

If you are mounting one flush with a wall, you probably will need either an in-wall speaker system or at least two traditional tower or bookshelf speakers. You would need as many as six speakers for 5.1-channel surround sound.

Those two front speakers don't need to be placed directly to the sides of the TV, but they do need to be set up in a way that allows for even sound dispersal throughout the listening area. If a surround-sound system is used, placement becomes more critical. The center-channel speaker, for instance, should be placed close to the TV screen to help place dialog near the televised mouths that are speaking.

Wires, cables and cords

No matter where a plasma or LCD screen is placed, no one wants to see all the cables.

In addition to the power cord, there could be just one cable if the TV is used strictly as a monitor from an audio-video receiver that does all the switching among playback devices. If the video switching is done at the TV rather than at a receiver, there could be separate cables for an antenna, a cable or satellite feed, a DVD player, a VCR or a computer.

Before installing a TV in a wall, establish how those signals will get there. Will cable be fed up or down a wall from the receiver and back down or up behind the TV? Will audio-video devices be in another room with cables fed from there and the devices operated by a remote control that can work through walls?

Wireless connections loom, but they don't perform well enough now to replace hard wiring.

Don't be afraid

All this may sound intimidating, but it shouldn't stop you from buying the television that you have been dreaming about. Just like any other home technology purchase, remember that you need to think ahead — and that the price first quoted in the newspaper or showroom probably won't be the final amount you spend.