The home cinema market is one of the fastest growing in the world today. A plethora of new technologies and ever-improving products have found their way onto dealers` shelves and into shop windows. The purchasing decision is increasingly difficult, particularly as prices are falling due to the strong rand and the competitive nature of the market.
Andre Rossouw, a technology specialist at Rectron, looks at the latest developments in this arena and suggests a low cost option that, he predicts, will take the home - and business - market by storm.
It`s show time. And it`s all about big sound and big screen action. Impact is the name of the home cinema game. For many thousands of converts to this form of entertainment, there is good news. New technologies abound and prices are sinking faster than the Titanic - thanks to our stronger rand and the high level of competition among vendors.
But what to buy? The most obvious starting point is the screen itself. It must be big. A large format conventional TV would do the trick, but it wouldn`t have the impact of something like a plasma screen, or the new kid on the block - projection screens.
It`s a popular fallacy - a left over from the TV era - that screen size should be closely matched to the dimensions of your room. Home cinema dictates its own rules. Enthusiasts can buy as big as they can afford and enjoy movies on the grandest of scales.
Plasma vs projection
While there are many options to choose from, large plasma screens and projection technologies are two of the most popular.
Plasma screens are big, expensive displays. They were originally intended for information displays in corporate reception and public areas - such as airports - but their "hang-on-the-wall" nature has given them a place in the home cinema too.
How do plasma screen TVs work? Passing a high voltage through a low-pressure inert gas causes it to emit light. The gas ionises and is converted into plasma form - hence the technology`s name.
Plasma pictures are not the clearest, so they are not often the best choice for a small room. Another disadvantage of plasma technology is its susceptibility to screenburn. For this reason, it is useful to avoid channels with bright static logos, or irreparable damage to the screen could result.
Projection - the ultimate
Many home cinema addicts believe that projection television has taken home cinema to its ultimate limits. No longer is the viewing experience restricted by the physical constraints imposed by a TV tube.
With a front projector system, running directly from a DVD player, an entire wall of your lounge becomes your TV screen. Movies appear as they would in the cinema and they are best viewed in total darkness for effect.
Projectors fall into three categories - tubed, LCD (liquid crystal display) and DLP (digital light processing).
The tubed projector is a box with three lenses. They focus separate red, green and blue images on to the screen to build a picture as large as you like. This type of projector is used in cinemas, conference venues, meeting rooms and at public displays.
Tubed projectors are fixed assets that are usually installed by experts and then rarely touched. They are typically mounted on the ceiling or floor in the middle of the room.
Sometimes, the projection tubes are built into a cabinet along with the screen. These rear-projection TVs also include Nicam TV tuners and appear much as conventional direct-view TVs - but on a much larger scale.
There are two other options, LCD (Liquid Crystal Display) and DLP (Digital Light Processing) projectors. Both technologies de-interlace the picture (so no lines are visible), can be moved from room to room, and require no more setup than a slide projector.
At the heart of the LCD device are a number of liquid crystal panels. They are illuminated by a single high wattage metal halide lamp. A series of dichroic reflectors and filters split the spectrally pure white light into rays of red, green and blue. Each of these beams illuminates one panel.
The images from the panels converge at the focal point of a single lens.
The traditional disadvantage of LCD has been pixelation - the individual cells that form the picture become obvious when magnified by the lens. But this is now less of a problem because newer models have higher resolutions.
The DLP solution
A solution for both home and business applications is DLP technology projectors. They employ a Digital Micromirror Device (DMD) chip, which consists of a matrix of individual cells, each of which contains a microscopic hinged mirror.
When a charge is applied to a cell, the attractive force causes the micromirror to angle towards it. The reflective properties of the mirror are thus changed, and light bounced off it will contribute one illuminated pixel to the picture.
The more upmarket DLP projectors employ three DMD devices and a series of dichroic filters. In this respect they are not dissimilar to many LCD units.
Less expensive DLP projectors use a single DMD to rapidly fire a sequence of each picture frame`s red, green and blue components at a revolving colour wheel.
The images are routed via the optics and projection lens to the screen: the eye combines them into a colour picture. DLP projectors can produce bright and detailed images, with none of the lag associated with some LCD models.
Running costs
One question associated with projection technology is the running cost. Lamps and high intensity projection tubes are not as long lasting as TV tubes. With LCD or DLP projectors, a lamp life of 2 000 hours is often quoted.
By then, the colour temperature of the lamp will have dropped considerably, producing an orange-tinged picture.
The good news is that the cost of budget projectors and their lamps are falling rapidly. Get in line today. It`s time to get your ticket to the home cinema experience.
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