1. Sound Types and Functions
Movies engage two senses:
vision and hearing.
Spielberg says “the eye sees better when the sound is great” … but why?

2. Sound
Sound should be integral to all three phases of film production (preproduction, production and post productions), not an afterthought to be added in postproduction only.
A film’s sound is potentially as expressive as its images.
Image and sound can create different worlds.

3. Describing Film Sound
Pitch (or level) of a sound can be high (like the screech of tires on pavement), low (like the rumble of a boulder going down a hill) or somewhere between these extremes. Pitch is defined by the frequency (or speed) with which it is produced (# sound waves/second).
Loudness (or volume or intensity) of a sound depends on its amplitude. The greater the amplitude of the sound wave, the harder it strikes the eardrum and the louder the sound.
Quality (or timbre, texture or color) of a sound that includes those characteristics that enable us to distinguish sounds that have the same pitch and loudness.
Fidelity is a sound’s faithfulness (or unfaithfulness) to its source.

4. Sources of Film Sound: Diagetic & Nondiagetic
Diagetic sound originates from a source within a film’s world. Internal, external, onscreen or offscreen and recorded during production or constructed during postproduction. Examples include steps on pavement, a knock on a door, the ring of a phone, conversation between characters…
Nondiagetic sound comes from a source outside that world. It is offscreen and recorded during postproduction, and it is assumed to be inaudible to the characters onscreen. The most familiar forms of nondiegetic sound are musical scores and narration that is spoken by a voice that does not originate from the same place and time as the characters on the screen.

5. Sources of Film Sound: more types
Onscreen versus offscreen sound.
Simultaneous (diagetic and onscreen) and nonsimultaneous sound (like a flashback sound)
Internal (hearing thoughts of a character in a scene) versus External Sound (a place within the world of the story, we assume it is heard by the characters in that world. Could be onscreen or offscreen.)

6. Types of Film Sound: Vocal sounds (Dialogue, narration)
Environmental sounds (Ambient sound, sound effects & Foley sounds)
Music (diagetic or non-diagetic, onscreen or offscreen)
Silence

7. Functions of Film Sound:
Audience Awareness
Sound can define sections of the screen, guide our attention to or between them, and influence our interpretation.
Audience Expectations
Sounds create expectations.
Expression of Point of View
By juxtaposing visual and aural images, a director can express a point of view.
Rhythm
Sound can add rhythm to a scene, whether accompanying or juxtaposed against movement on the screen.
Characterization
Identifying characters, occurring and recurring on the soundtrack as the characters make entrances/exits but also underscore characters’ insights.
Continuity
Sound can link one shot to the next, indicating that the scene has not changed in either time or space.
Emphasis
Sound can create emphasis in any scene – that is, can function as a punctuation mark- when it accentuates and strengthens the visual image.
Emotional, psychological and physiological reactions are enhanced by sound