PICTURE PERFECT PLASMAThe Resolution Revolution
Now that High Definition Television (HDTV) and flatscreens have come to stay, there remains only one question when you upgrade: plasma or liquid crystal display (LCD)? As with the technology battle between VHS and Betamax video, you want to bet on the right horse.
You most likely grew up with CRT technology powering your family's box. Those cathode ray tubes, which seemed good enough when we stared at the test patterns for hours when television was first launched in South Africa during the 1970's are, however, too heavy and bulky to function in today's ultra-thin flatscreens of ever-growing size.
So the problems that manufacturers have been trying to overcome as screens grow bigger: weight, bulk, size, colour quality including brightness and contrast, sharpness, response time, viewing angles, screen burn and energy usage. Manufacturers do make an inordinate amount of noise about lifespan, and the average television set is expected to deliver 60 000 hours (27 years) of viewing at an average of six hours per day. I must say, however, I have never owned any set for even half that time and fully expect these same manufacturers to lure me back into the shop with even better technology long before the expiry date of my current set.
With CRT now evidently out of the race, the choice comes down to plasma or LCD. Plasma displays work much in the same way as fluorescent and neon lights - that is, they use electricity to illuminate a gas sandwiched between two glass plates with transparent electrodes. When voltage is applied to one of the electrodes, a surface electrical discharge produces ultraviolet rays that excite the coloured phosphors coated inside the opposite plate of glass, emitting light through the glass plate to create an image. Because the phosphors are red, green and blue, the image produces is in colour.
LCD's are thin, flat display devices made up of any number of colour or monochrome pixels arrayed in front of a light source or reflector. Manufacturers in this area have been able to overcome most of their early "ghosting" problems and are fast playing catch-up in the international large screen HDTV market dominated by plasma, and quite often because their claim to lower energy consumption does seem to resonate with high-end luxury users.
There is no outright answer as to which of these technologies are better, and speaking to a specialist at Balanced Audio in Johannesburg, Jannie Dirks, his best suggestion is "decide what you want to watch, and how you want to watch". He must have seen the puzzled look on my face, as he explained further. "The ideal viewing distance for television is generally that for HDTV, you should be at a distance of 3 to 4 times the height of your television set. The larger, the further away you will be sitting, and that might be limited by the actual space in your TV room." We all know that the impulse is always to go for the biggest set possible, so let's assume then, that you take home something big. This is where the choice between plasma and LCD becomes important. Here is the rule of thumb, which we should add, would be greatly disputed by many an expert: once you go over a 94cm screen (that's the diagonal they measure), plasma is better suited.
When it comes to colour, plasma shows some advantage with a slightly bigger range. LCD colours are effectively produced by "taking away" colours from pure white, via the manipulation of the light waves coming from a constant, rear backlight.
This makes it more difficult for LCD to deliver consistent vibrancy and authentic tones, with particular problems being over-dominant greens and reds, and an overall colour "temperature" that's too high to ideally suit video material. On the contrast side, plasma's pixels individually create their own light source independent of other pixels, meaning that only the bright parts of an image need to light. This results in deeper black levels. With LCD's, individual pixels need to block out bright light from the constant backlight to make themselves dark, and since they can't achieve this completely, they typically don't reproduce blacks as well as plasma displays do.
The team at Balanced Audio's emphasis on what you like to view becomes important when talking about response time. Sit up and listen all you sport fans. A screen's response time is a measure of how fast its pixels can complete one full cycle, or how fast it is ready for the next image's light needs. With LCD, completing a pixel cycle requires it to go from active (black) to inactive (white) and back again. Since each pixel is completely self-contained, plasmas can refresh themselves virtually instantaneously. Plasma pixels react so fast that the term "response time" is practically irrelevant, as even the fastest movement looks crisp and clear. This seems to me to be the absolute slam-dunk argument for plasma in sports-crazy South Africa, and Jannie Dirks tends to agree with my sentiment when I make that observation. It is for this very reason that Balanced Audio sees these huge plasma screens almost walk themselves out the front door right around major sporting events like the Olympics, or the rugby and cricket seasons' best.
Should I still have had some lingering doubt, one of Jannie's collegues reminds us both that the reason why sport crazies often purchase large screens is to have a few friends over to enjoy the game with them. The final criterion that comes to mind, then, is the viewing angle. You do not all want to have to fight for the front seat in the middle to catch the game. Plasma screens can be watched from very wide viewing angles without any significant loss in colour or contrast, thanks to the fact that they emit light directly from each of their screen cells or pixels. LCD pixels merely pass on a light originating from a sigle point behind them; therefore, LCD screens can lose contrast and colour if watched from angles as small as 45 degrees.
So, with Jannie's help, I know where I am putting my money in time for Saturday's game. But, why don't you rather drop in at a specialist store such as Balanced Audio and let them help you make the right choice for your family's viewing requirements. Yeah - as if dads buy large flatscreen TVs with more than their own sports viewing needs in mind!
