TITLE: 1. UNDERSTANDING THE PURPOSE OF DIEGETIC AND NONDIEGETIC SOUND

Diegetic and Non-diegetic 

Diegetic sound whose source is visible on the screen or whose source is implied to be present by the action of the film: voices of characters.

Sound whose source is visible on the screen 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 ( = source music)

Diegetic sound is any sound presented as originated from a source within the film's world 

Diegetic sound can be either on screen or off screen depending on whatever its source is within the frame or outside the frame.

 

Non Diegetic - When everyone is chilling, we hear exactly what the characters can hear

Diegetic - Is what the characters can't hear and we can hear (soundtrack)

Sound whose source is neither visible on the screen nor has been implied to be present in the action: 

• narrator's commentary
• sound effects which are added for the dramatic effect
• mood music

Non-diegetic sound is represented as coming from the source outside story space. 

The distinction between diegetic or non-diegetic sound depends on our understanding of the conventions of film viewing and listening.  We know of that certain sounds are represented as coming from the story world, while others are represented as coming from outside the space of the story events.  A play with diegetic and non-diegetic conventions can be used to create ambiguity (horror) or to surprise the audience (comedy).