Hey, I just wanna watch a movie. What’s the deal with this surround sound number soup?
In the last post I talked about the various surround sound channels, the speakers that reproduce them and where they typically get placed in the room. If you look on the back of your DVD & Blu-ray disc “boxes” you’ll also see one or more of the numbers listed above. These numbers tell you how many channels of information are contained in the soundtrack of that disc. These descriptive numbers came about with the advent of Dolby Digital™ and later, DTS™. However, you may see them used on media that is not Dolby Digital or DTS compatible today.
1.0 – This means the sound is in mono. A single full-range channel is all that’s available from this source. The sound may come from more than one satellite speaker in the system, but they’re all reproducing the same information. If you’ve got a subwoofer your receiver may be set up to direct the bass frequencies to the sub, so in a sense you’ve taken 1.0 and made it 1.1 (1 channel to feed the satellite speakers and one with bass sounds only to feed the subwoofer).
2.1 – Stereo with a subwoofer channel. Stereo only would be expressed as 2.0 with the same caveat as above with 1.0. [Download Guide from Dolby Digital™]
5.1 – This has been the standard for contemporary multi-channel soundtracks and concert DVDs, both in Dolby Digital and DTS. Three front channels (Left / Center / Right), two primary surround channels (Left / Right) and a LFE (Low Frequency Effects) subwoofer channel. All these channels are discrete and digitally recorded. [Download Guide for 5.1 Surround Sound from Dolby Digital™]
6.1 / 7.1 – Adds one or two secondary (rear) surround channels. The primary surrounds are intended to be located to the sides of the listening position, these go in the back of the room. When the 6th and 7th channels were initially added they were encoded in the primary surround channels and extracted for playback so they weren’t “discrete digital” channels like the others in the system. The latest iteration of DD, Dolby Digital Plus™ does allow for discrete 7.1 channels of information but there’s few soundtracks that contain them. [Download Guide for 7.1 Surround Sound from Dolby Digital™]
9.1 / 11.1 – Front height or front width channels added to a 7.1 system as described in my earlier post. These channels are derived like the original secondary surround channels were.
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