Breaking the movie down or splicing all of the reels together and loading onto the platters normally takes about an hour for each procedure, for each movie. Many people ask about the different sound processing systems and what the differences are. The information below was obtained from the sound system producer's web-sites and from information provided by General Cinema. The information pertains mostly to indoor theaters, but is posted here as technical content for those of you that are interested. Three different speakers are located behind the screen and depending on the visual action on screen, the sound effects will be directed more towards one speaker than another.
Surround speakers provide environmental sounds such as thunder and rain.
Often, a fifth, or subwoofer channel, is also derived from the analog soundtrack. The amount of background noise inherent to analog recording is drastically reduced, thus expanding the dynamic range. For example, phonographic records have grooves of varying width which are mechanically read by the phonograph needle which then transmits the vibrations to the sound system. An analog motion picture soundtrack utilizes an area of light with varying width. Light is projected through the soundtrack on to a solar cell which then converts the light intensity into electronic pulses and then transmits them to the sound system.