Research: Diegetic and non-diegetic sound

The roles of diegetic and non-diegetic sound are very important as they both have totally different effects on the viewer and target audience. In this post I am going to be disguising the differences between both diegetic and non-diegetic and the effects they have on my viewers and target audience.

Diegetic 

Sound whose source is visible on the screen of whose source is implied to be present by the action on 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 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.
Another term for diegetic sound is actual sound.

Non-diegetic sound

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 is added for the dramatic effect
• Mood music

Non-diegetic sound is represented as coming from the source outside story space.
The distinction between diegetic and 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).
Another term for non-diegetic sound is commentary sound.