Ambient sound (AKA ambient audio, ambience, atmosphere, atmos or background noise) means the background sounds which are present in a scene or location. Common ambient sounds include wind, water, birds, crowds, office noises, traffic, etc.
Ambient sound is very important in video and film work. It performs a number of functions including:
Providing audio continuity between shots.
Preventing an unnatural silence when no other sound is present.
Establishing or reinforcing the mood.
There are several types of ambient sound used in film production. Their exact names and meanings may vary but these are some common definitions:
Matching ambient sound: Any ambient sound recorded to match the ambient sound of a scene.
Wild sound: Background noise with distinct sounds, i.e. more than ambient sound, which is not synchronised with the main vision. Example: Children playing in a playground.
Buzz track: A general term for ambient sound.
Room tone: The sound of an empty room, or a room in which all the actors are standing silently.