Sound is created by vibrations that move through air particles and create sound waves. The pitch of a sound depends on the frequency of vibrations, with higher pitches resulting from faster vibrations and lower pitches from slower vibrations. There are two types of sound used in films - diegetic sound, which comes from visible or implied sources within the story, and non-diegetic sound, which comes from sources outside the story like narration, music, or added sound effects. Diegetic sounds can be either on screen or off screen, while non-diegetic sounds are represented as coming from outside the story space.

1. Sound in TV and Film
Atif Ali

2. Use of Sound
Vibration
Tone
Volume
Pitch
Air
Resonate
Timbre
Wave
Pace
Rhyme
Tempo
Diegetic:
belongs to
the story
Sound
effects
Dialogue
(speech)
Ambient
(background
atmosphere)
Non-diegetic
Soundtrack
Songs
Voice over
Narrative

3. Sound
Sound is a type of energy made by vibrations. When any object vibrates, it
causes movement in the air particles. These particles bump into the particles
close to them, which makes them vibrate too causing them to bump into
more air particles. This movement, called sound waves, keeps going until they
run out of energy. If your ear is within range of the vibrations, you hear the
sound.
When the vibrations are fast, you hear a high note. When the vibrations are
slow, it creates a low note. The sound waves in the diagram show the
different frequencies for high and low notes.

4. Diegetic/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
• 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 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 a source outside story space.
The distinction between diegetic or non-diegetic sound depends on our understanding of the conventions of
film viewing and listening. 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.