Surround Sound Part I: 1.0 ... 2.1 ... 5.1 ... 7.1 ... 9.1 ... 11.1

"Hey, I just wanna watch a movie. What’s the deal with this surround sound number soup?"

We’ll define all those numbers and explain the various speakers in surround systems in order of importance and their typical roles:

Center channel speaker – This speaker is usually placed directly above or below the TV screen. It delivers up to 85% of the dialogue and 65% of the special effects in a soundtrack. Just think about how much of the action in any viewing experience is in the center third of the screen; all the sound for that action and more is going to come from the center channel speaker.

Left/Right front speakers – Ideally placed equidistant from the left and right sides of the screen, generally no more than 4 feet away, if possible. The L/Rs support the output from the center channel and reproduce sounds that show up on the left or right third of the screen. If a stereo source is being reproduced, all the information will come from these two speakers unless you’ve got a subwoofer in the system and the L/Rs are set to “Small” in the receiver menu.

Primary surround speakers – Ideally placed directly to the sides or a little behind the prime listening area. These typically reproduce the ambience or the environmental sounds in the movie or TV show scene. Jungle sounds, office sounds, restaurant sounds, city street sounds, stuff like that. In spite of everyone’s powerful desire to hear the surround speakers all the time, the truth is you shouldn’t be consciously aware of their existence most of the time. Trust me, the film director doesn’t want you constantly distracted by sounds coming from your side or behind you. Surround music on the other hand, may have just the audience sounds in these channels or the engineer may place primary info in these channels. Why do they do this? Because they can.

The above add up to the “5” in a 5.1 system. They’re all full frequency channels (20Hz – 20kHz) when recorded by the studio but you can choose to send the low frequencies to your subwoofer. 

More channels to come in the next post…