The Home Theatre market in the UK is growing at an alarming rate. All the major Hifi & TV manufacturers are producing Multi Channel Surround Sound AV (Audio Visual) equipment. The "standard" configuration is "Dolby Pro-Logic" which is a 4 channel system with 5 speakers located around the room. The 4 channels are LEFT, CENTRE, RIGHT which are located in front of the viewer and the SURROUND channel which uses a Pair of speakers placed behind the viewer. This may or may not be augmented by a SUBWOOFER which provides extra impact for Low Frequency sounds e.g. Explosions, Earthquakes, Thunder etc.

The next step up the Cinephile ladder is THX. This is not so much a system but a specification which lays down minimum standards for equipment. THX was developed by Tom Holman at Lucasfilm (Tom Holmans eXperiment) and was primarily intended to ensure that when a movie was shown in a theatre it would sound the way the Director and Sound Engineer had intended.

"Dolby Digital" is the latest generation of Surround Sound of which the home version is called Dolby AC3. This gives 6 discrete channels of CD quality audio and is also referred to as 5.1
LEFT, CENTER, RIGHT, LEFT SURROUND, RIGHT SURROUND and SUBWOOFER

LCD (Liquid Crystal Display)	Still in its infancy LCD technology uses a colour LCD panel through which is shone a very bright light source which is then focused onto the screen. This type of projector can suffer from the "Chicken Wire" effect. So called because the individual pixels of the display can be seen if the image is viewed too closely giving the impression that someone is holding a piece of chicken wire between you and the screen.
The "Newborn" display technology uses a DMD chip from Texas Instruments. This chip contains over 400,000 "Micromirrors" in an area about the size of your thumbnail. These mirrors deflect a light source to create the image. I have recently fitted 2 of these projectors and the image is vastly superior to LCD	DLP (Digital Light Processing)
CRT (Cathode Ray Tube)	Tried and trusted technology which uses 3 small (about 6-9") TV tubes 1 Red, 1 Green, 1 Blue to project 3 images onto the screen. These images need to be accurately converged to obtain a clearly focussed image but once set up correctly provide the best image. The only drawback of a CRT projector (or any projector to some extent) is that the room needs to be darkened slightly. But Hey! When was the last time you went to the movies and they left the lights on? If you have enough money (won the lottery lately?) the image can be further enhanced by the addition of a Line Doubler or Quadrupler which digitally converts the 625 line TV signal into a 1250 line image giving similar results to 35mm film.

If you are driving a 60 watt speaker at 8 watts from a 10 watt amplifier any explosions or similar loud effects will result in the amplifier clipping, giving at best a severely distorted sound and at worst resulting in the destruction of the tweeters. This happens because when an amplifier goes into clipping the output is rich in high frequencies (which may be so high as to be inaudible) that overload the tweeters. The tweeter in a 60 watt cabinet may only be rated at 10 watts as most of the energy in an audio signal is at the low end of the range. By comparison, a much larger amplifier e.g. 100 watts will reproduce the peaks without distortion. This may overload the bass driver momentarily but as long as this is not sustained, no damage will occur. Because there is no distortion the rest of the system will not be overloaded. The end result is a much cleaner sound with the ability to blow your socks off!

At the end of the day sound and picture quality is very much a subjective issue. What looks and sounds perfectly acceptable to one person may be totally unacceptable to another. However some people (with more money than sense) simply must have the most expensive. They then spend all their time looking and listening for imperfections in the performance. This to me is totally missing the point. The best advice I ever heard was