Sound terms

Diegetic

Diegetic sound is sound that comes from the clip within the scene or whose source is implied to be present by the action of the film: voices of characters. sounds made by objects in the story. music represented as coming from instruments in the story space. An example of diegetic sound would be dialogue;

This scene from Pulp Fiction (1994) has no non-diegetic sound and purely focuses on the diegetic dialogue coming from within the scene. 

Non-Diegetic  

Sound whose source is neither visible on the screen nor has been implied to be present in the action and is represented as coming from the a source outside story space. An example of non diegetic sound would be a soundtrack or incidental music;

This clip from Once Upon a Time in the west (1968) heavily uses a non-diegetic soundtrack to create atmosphere rather than diegetic sound.


Sound bridge

Sound bridges is used a lot for continuity editing style, in which the connection between both scenes set by the mood (suggested by the music) is still the same, in which the sound bridges over the transition between one scene to another. 

For example, the sound bridge in The Matrix is the alarm clock which starts off in one scene as non-diegetic sound and the camera cuts to the next in which the alarm clock becomes diegetic sound.

Sonic flashback

A sonic flashback describes the technique of using sound from earlier in the film during a later scene. One character may be present on the screen, but they are hearing a voice or action from a previous time in their head.   

For example, in Kill Bill (around 48 seconds into this clip) there is a loud alarming sound, in which is used repetitively throughout the film as a symbol for when she faces her enemies.

Voice over

A voice over is non-diegetic in which you can hear the voice of a character and/or narrator speaking but the character not speaking those words on screen. This is often used to reveal the thoughts of a character through first person narration.   

For example, the opening to The Breakfast club uses a voice over to describe to the give the audience an idea for what is going on and so they become intrigued.

Contrapuntal 

Anything contrapuntal has to do with counterpoint, in which the incidental music or soundtrack used contradicts the situation of the scene in the film. 

For example, in Reservoir Dogs, the man in the suit uses light hearted upbeat music in a situation which is clearly not suited to the music set up. This creates a more unsettling feeling to the situation and emphasises the panic of the man being tied up.

Sound perspective

Sound perspective refers to the apparent distance of a sound source, evidenced by its volume, timbre, and pitch. Sound perspective can also give us clues as to who and where is present in a scene and their relative importance to the film’s narrative.

For example, during the fight scene from Kill Bill, the water feature can be heard in the background of the shot, in which the camera then cuts to a close up of the water feature and the sound becomes louder.

Ambient
  
Ambient sound means the background sounds which are present in a scene or location. Common ambient sounds include wind, water, birds, crowds, office noises, traffic, etc.

For example, in Jaws the ambient sound would be the people talking on the beach as we are aware they are in the background but they aren't on screen. This is done to create a busy atmosphere without showing all the people within the shot.