Surround sound: from 2.0 to 7.1 and beyond

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Surround sound systems can be confusing when reviewing how many audio channels they have, and this includes sound bars, which are not simply one long speaker.

Let’s go through and review what the different numbers mean when you look at a system that says Dolby Digital 2.0 or 5.1 Channel DTS. The gist is that the numbers refer to discrete speakers — or really channels, as you can have one speaker that plays more than one channel.

— 2.0 means right and left stereo sound with two distinct channels. This is just like your old stereo systems that separate sounds to create a more full experience. Almost all devices you have with two speakers will at least have stereo sound.

— 2.1 adds in a subwoofer for a separate bass sound. The subwoofer only gets counted as one tenth of a channel; this is because it is not distinct sounds that come through the bass, but rather low frequency effects. Many sound bars have 2.1 surround; you have stereo sound but also the subwoofer helping to fill in more depth to the audio. Sometimes the subwoofer is even built into the sound bar, which can muffle sounds a bit.

— 3.1 adds a center speaker to separate audio dialogue that has been processed for a distinct channel. The right and left channels are still distinct and the third channel/speaker is between them. This can be found in sound bars and home theater systems that have three speakers or a bar in the front and then a separate or built-in subwoofer.

— 5.1 adds in two rear speakers to the mix. The new channels offer rear surround sound and with higher quality processing on even right and left channels (Dolby Digital 5.1 has 5 distinct channels plus subwoofer, whereas the older Dolby Pro Logic only has the rear sound in mono as opposed to stereo). This is the sound that most people are looking for in a home theater system. When watching something move in a circle on TV like a helicopter, the sound can travel from directly in front of you (center channel) to your right (right front speaker), behind you on your right (right rear speaker), continue on behind you to your left (left rear speaker) and end on your left in front of you (left front speaker) — all the while with some bass added in for low-frequency effects.

— 6.1 adds in an additional back surround channel that is like your center channel, but for sound behind of you. This is a less common setup but still available, nonetheless.

— 7.1 adds in two inward facing side speakers, but my research shows that DVD movies are not made with 7.1 discrete channels for viewing in the home (Blu-Rays can be). Of course, in a movie theater there are many more channels and speakers!

With even more channels there are more speakers added to create a complete surround sound effect. Systems can have 8.1, 9.1, and so on.

Confused yet? The most common configurations are 2.0, 2.1 and 5.1. If you want to hear the sound behind you, then 5.1 is the way to go.

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Paul Burnstein is a Tech Handyman. As the founder of Gadget Guy MN, Paul helps personal and business clients optimize their use of technology. He can be found through www.gadgetguymn.com or via email at paul@gadgetguymn.com.

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