Home Theater Audio – What’s Multichannel Audio?
“Hi-Fi” and stereo were the large things for audio enthusiasts decades ago. Many people even bought vinyl records of sound effects just to marvel in the fidelity and stereo effects. Quadraphonic sound was tried for a time, but systems were expensive and recording and media required 2 additional channels. In the last decade digital audio has made even more sophisticated systems not merely possible but also affordable.
Multichannel surround sound, Dolby, and THX
Stereo uses 2 recorded sound channels to give a left speaker plus a right speaker, roughly akin to our left and right ears. Multichannel surround sound processes additional channels to enhance the audio exposure to additional speakers. There’s several kinds of surround sound. The first uses a fixed listener location for a 3-dimensional audio effect. Unfortunately and also this means there’s a single “sweet spot” the location where the effect works best. Other forms use speakers behind the listeners with an audience-wide experience. Each speaker feed is termed a channel.
Audio processing from Dolby Laboratories began long ago in the 1960s with noise reduction. Dolby processing has evolved to multi-channel surround-sound processing through a succession of small steps. Probably the most recent is Dolby TruHD. This allows loss-less encoding (no information lost, no noise added) of 8 or maybe more channels.
You may have read about receivers boasting about THX. THX is not really a recording, encoding, or multichannel surround sound technology. It’s actually a quality standard and certification system. Originally employed for movie theaters, it “guarantees” high-quality multi-channel sound.
5.1 Channel Systems
The most frequent arrangement today uses 6 speakers, and it is referred to as 5.1 channels. The “.1″ channel is for a sub-woofer dedicated to powerful very low frequencies. A good sub-woofer is especially important for movie and gaming special effects. Two of the residual speakers are the standard stereo speakers. Another pair can also be stereo, but these “rear” speakers they fit behind the listeners. Which means you literally are flanked by sound. The final speaker can be a middle speaker, placed between your front stereo pair. Ideally, it’s mounted fairly high use a broad sound experience.
7.2 Channel Systems
Add 3 more speakers and you have a 7.2 channel system. Many current receivers can only handle 5.1, so be sure to choose one that can handle the 9 speakers in order to go with this arrangement.
The “.2″ speakers are two sub-woofers, making your deep bass truly stereo. The remaining pair can be used in a number of ways. The best sound originates from placing them in front above the main stereo pair. Here you’d position the middle speaker a little lower. You can also put them further to the left and right of the main stereo speakers. Finally, you can use them as remote speakers in an entirely different room.
Wrapping Up
These may sound like complicated systems, but each channel and speaker have their purpose and place. They’re not really that difficult to setup. You may have to be clever in running wires towards the rear speakers in order that they’re not too visible, but wireless stereo speakers are available if this is too much trouble. Either way, it’s definitely worth the effort. Installing a property theater surround sound system will raise your music listening, movie watching, and even video gaming to a totally new level.
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