Surround Sound is audio playback utilizing 2 or 3 dimensions – as opposed to one dimensional audio (mono or Left-Right Channel).
*5.1 Surround Sound – standardized audio layout utilizing 6 independent audio channels including: front channels (Left, right and center Channels) , Surround Speakers (Left), and a sub woofer for low frequency signals.
*6.1 Surround Sound – Standardized audio layout that included all the audio channels of 5.1 Surround sound but with the addition of a rear surround speaker.
*7.1 Surround Sound – Standardized audio layout similar 6.1 Surround Sound with the difference of having 2 rear surround speakers. Currently there is very little audio/video encoding support for the 7.1 layout