After the completion of a home theater system, with out fail the
customer will ask something along these lines "why don't I
hear the speakers in the back?". The reason for this is surround
sound. What that means, in laymen's terms, is that the sounds
comes from the speaker that the movie director has decided it should
at any given time. For example, when two people are having a conversation
then the vast majority of the sound will come form the center channel
speaker. Another would be when a plane flies from the right side
off the screen to the left, the sounds moves from the right speaker
to the the left.
There are several speaker layouts and formats of surrounds sound.
The basic 5.1 speaker layout includes a center, right, left, back
right, back left speakers, as well as some kind of sub woofer. The
7.1 includes two extra speakers located between the front and back
speakers.