Understanding Surround Sound Formats

Know the difference between various surround sound formats

If you're in the market for a surround sound system, chances are you've encountered a number of different surround sound formats. While it's important that you understand the differences between these formats, the technical aspects of surround sound can initially seem very confusing to the lay person. As part of your consumer education initiative, it's important that you learn to distinguish the unique features of each format so you choose the one that's best for your intended application.

An Overview of the Various Surround Sound Formats

Here's a run-down of the most common surround sound formats, and how each differs from the others:

  • Dolby Digital. This is a compression format which contains up to six different sound channels, including five channels for speakers which operate in "normal" ranges. Thus, if you're getting a 5.1 surround sound system, Dolby Digital is a compatible format.
  • DTS and DTS-ES. DTS is a multichannel audio codec format which is primarily used with video game systems, particularly the Xbox 360 and PlayStation3. DTS-ES is an enhanced version of the primary codec, which adds center-surround audio channels and is compatible with 6.1 playback.
  • Dolby Digital EX and THX Surround EX. These formats add an additional channel which improves the localization of specific sound effects. If you're running Dolby Digital EX or THX Surround EX on a 5.1 system, this additional channel will be dropped; you need a 6.1 or 7.1 channel output to experience the difference.
  • Dolby TrueHD. This is the brand name for a type of audio codec which permits lossless rendering of sound; it supports features including dialogue normalization, metadata, and dynamic range control.
  • Dolby Digital Plus. This format adds additional channels, permitting up to 13-channel playback, along with increased bitrates for sound rendering. Blu-ray disc players give you the option of grafting these additional channels onto standard 5.1 playback for modest sound enhancement, though this format works best in a 7.1 system.

It's important that you get all your questions answered before committing to a particular system or product. If you'd like to learn more about the features and capabilities of a specific surround sound format or system, ask the vendor for assistance.

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