1. When watching a movie, surround sound brings life to pictures. It's obvious then when the actors go through a crowded place and the sound of people comes from all directions like in real life, or when a car comes from left rear to front right and you can hear it goes all the way in three dimensions image, that makes you feel like you are in the movie.
The data to the amplifier how to power each speaker is
hidden in the basic format - in the video surround cassette , for example.
(By the way, in films, there was a problem where to locate the surround
sound data because the side of film is occupied by movie sound track. Dolby
found a way to locates the surround data between the holes in edge of the
film)
2. When listening to a concert in a hole, or in a church, or in a stadium, even if listening to the same band, the sound will differ in each place. The reason for this is the different acoustic environment each place gives. One reason for for the different sound is the fact that the listeners hear each sound twice (or more, in a very short time of course) once from the source and then when it comes rear from the walls around.
The reflected sounds from walls are unique for each place. Surround sound system has a computer in sound path. The computer is programmed for several famous places. The programmers of the system know in each place how much time it takes to the sound to be reflected from walls, they also know the unique parameters of each place.
When listening to system, the two main speakers on front play like ordinary stereo speakers. The sound that goes to rear speakers, after a wanted delay with the same parameters the computer gives it, so the listener gets the impression he seats in the concert hole he likes.
It's important to know that a surround system needs two good speakers on front but there is no need to buy expensive speakers to the rear wall because these speakers only give the surround effect.
In this way, the amplifier can create the surround sound
when its input is a regular stereo.
To my opinion, surround sound is a very good way to watch movies, but it's not a very good way to listen to music. A good stereo system gives amazing image feeling like in real life. I like the sense that the band is playing in front of me at my home with my own walls reflections...
But there is a way to enjoy both worlds. You can buy a quality stereo equipment with a pair of quality speakers and add on a prologic detector with cheap rear speakers. The central speaker can be the T.V speaker so there is no need to buy one.
If doing so, check if the rear speakers, where are not
in use, don't confuse the sound from main speakers. Check it by turning
the front of the rear speakers to the wall while listening to the mains.
If it does confuse the sound, you can cover the rear speakers while listening
to stereo only.