What is 5.1 surround sound ?

[tellboy]

I keep seeing 5.1 surround sound. Does this mean using 5 speakers ?

[spat]

no six
it is one of several surround sound formats
it is achieved with two front stereo speakers
two rear stereo speakers
one front central speaker and one subwoofer
http://entertainment.howstuffworks.com/movie-s ound4.htm

[fo3nix]

sometimes you also can find 4.1, etc. the .1 is the subwoofer for the bass.