Film sound is carefully crafted in post-production to emphasize key elements and set atmosphere through selective and ambient sounds, which can exist within the film's world (diegetic) or come from outside of it (non-diegetic). Sounds are either synchronous to match actions, asynchronous from outside the story, or contrapuntal to create a different meaning by clashing with visuals. Voiceovers and theme music are also used to guide the audience or indicate the film's personality.

1. Sound
Film sound is as important and carefully controlled as the visual elements of a
text. Although sound is often recorded on set, most film sound is added in
post-production.
Selective sound- used to emphasisekey sound elements within a sequence.
Ambient sound- used to create a particular atmosphereor a physiological
impact.
Sound can be-
Diegetic- that it exists within the world of the film.
Non diegetic- it emerges fromoutside the world of the film.
Film sound can be either-
Synchronous- when thesound effect is matched with another technical event
or action.
Asynchronous- when thesound originates from outside the diegetic reality of
the film; musical soundtrack.
Contrapuntal- noise or sound effect which doesn’tmatch the visual, often
juxtaposed to create an alternative meaning.
Other elements of sound-
Voiceovers- the voice of a character; often guides or informs the external
audience but can be used to push them in the wrong narrativedirection.
Theme music- the music that indicates, develops and ends the film. Indicates
the personality of the movie.