Home Theater Audio – What’s Multichannel Audio?
† Sunday, October 30th, 2011“Hi-Fi” and stereo were the large things for audio enthusiasts decades ago. Some people even bought vinyl records of sound clips just to marvel in the fidelity and stereo effects. Quadraphonic sound was tried for a while, but systems were expensive and recording and media required 2 additional channels. During the last decade digital audio makes even more sophisticated systems not only possible but also affordable.
Multichannel surround sound, Dolby, and THX
Stereo uses 2 recorded sound channels to feed a left speaker and a right speaker, roughly akin to our left and right ears. Surround sound processes additional channels to enrich the audio exposure to additional speakers. There’s several kinds of surround sound. The first runs on the fixed listener location for a 3-dimensional audio effect. Unfortunately this means there’s a single “sweet spot” where the effect works best. Other forms use speakers behind the listeners with an audience-wide experience. Each speaker feed is called 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. Just about the most recent is Dolby TruHD. This allows loss-less encoding (no information lost, no noise added) of 8 or 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 useful 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 perfect for a sub-woofer dedicated to powerful really low frequencies. A good sub-woofer is especially important for movie and gaming special effects. Two of the remaining speakers are the standard stereo speakers. Another pair can be stereo, but these “rear” speakers they fit behind the listeners. So that you literally are encompassed by sound. The final speaker is really a middle speaker, placed between the front stereo pair. Ideally, it’s mounted fairly high to supply a broad sound experience.
7.2 Channel Systems
Add 3 more speakers and you’ve got a 7.2 channel system. Many current receivers is only able to handle 5.1, so make sure to choose one that can handle the 9 speakers if you want 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 arises from placing them in the front above the main stereo pair. Here you’d put the middle speaker a bit lower. You can also place them further to the left and right with the main stereo speakers. Finally, you can use them as remote speakers in an entirely different room.
All in all
These may sound like complicated systems, but each channel and speaker has its own purpose and place. They’re not really that difficult to set up. You may have to be clever in running wires for the rear speakers in order that they’re not too visible, but wireless stereo speakers are available if this is an excessive amount of trouble. Either way, it’s definitely worth the effort. Installing a house theater surround sound system will raise the music listening, movie watching, and also video gaming to a completely new level.
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