Best viewed in "landscape" mode.
The center channel is the most important, followed by the main left and right speakers, followed by the rears (and sides, high fronts, low rears, second sides, etc. ).
Home Theater has taken the audio and video experience and revolutionized it for the consumer. Films have always been more enjoyable when the soundtrack is played through decent equipment - I have been plugging my television (and later, my VCRs) into my stereo since 1981. Stereo VCRs and tapes went a long way to bringing some at-home realism to the experience - but with the advent of Dolby Pro Logic, which allowed the encoding of a center and rear channel of sound in a stereo mix, things started to get really interesting.
I will try to explain, as briefly and clearly as I can, a few things about Home Theater, some of my opinions and prejudices about it, and how the products I build can help you get the most out of it.
Dolby Pro Logic enabled the accurate extraction of a front center and a rear channel signal from an encoded analog stereo source. While usually two rear speakers are used, Pro Logic actually only contains information for a mono rear signal - it usually sounds better coming from both sides of the rear rather than just the middle. The center front channel serves the useful purpose of tying the dialogue (and any "middle" sound effects) to the screen, avoiding the problem of them sounding like they are coming from the nearest main speaker if one is seated in an off center position. This is really important in a movie theater where some seats are far to the left or right.
These extra channels of sound allow the creator of a film to place you "in the action," to fill your room with the sound of the space they are trying to create, and it can be very involving. The ideal outlets for this, of course, are movies which take advantage of special effects - the ones full of explosions, rockets, and other "things that go whoosh" over your head.
The arrival of affordable DVD players, an increasing number of titles, and Dolby Digital decoders in receivers has taken this a step further. The digital signal provides several discrete audio signals with no decoding required. Channel separation is distinct and so the imaging all about your room is sharper and more detailed, and of course since the source is digital, you get what can be CD quality, hiss-free audio. The simplest, used for older stereo-only or mono sources, is called "2.0". Some lower budget films may be in "2.1" or "3.1". The most common matrix is "5.1" - left, center, and right in the front, and left and right surround/rear channels. "7.1" provides discrete surround (side) and rear signals. The ".1" (and sometimes ".2" part refers to the "subwoofer" channel, about which I tend to have my own opinions, attitudes and advice.
In order to get the best possible effect from all these speakers placed around your room, it is important, just as with two stereo speakers, that they sound the same - in fact, ideally, they shouldn't "sound" like anything at all but be completely neutral. With front, center, and rear speakers that all share the same design characteristics the various effects in the soundtrack will be seamlessly reproduced from whatever angle they are intended to be coming from.
To this end, I build a center channel speaker, the HUMAN C2+, which uses the same type of components and shares the same design strategy as my main "stereo" speakers. Due to the close family heritage shared with the classic EPI and Genesis products, this speaker also works wonderfully when they are your main speakers. Like most center channel speakers, it is horizontal rather than vertical, and symmetrical about its center line. Unlike most, it is a serious speaker in its own right, in fact some of my customers have set up their systems with five or six of these, setting them up vertically for the left and right pairs. Due to my own demand for a higher power center channel, I have also developed the HUMAN C3+, which is based on the HUMAN 88-41 double 8" three way system.
Rear speakers can be smaller than your main speakers if you desire. This is because surround systems can be set up to not send any very low bass to the rear. They should still, however, have the same level of sound quality as your front speakers. The best results are achieved with identical speakers for the front and rear, of course. Any of my speakers will not only work beautifully as main stereo speakers but make great rear speakers as well. My simple, elegant eight inch two way speaker, the HUMAN 81, for instance, makes a perfect rear speaker in a system using HUMAN, EPI, or Genesis main front speakers.
Chief Cook and Bottlewasher
7 Kelsey Road, Lee, New Hampshire 03861