Sound and Film

Sound refers to everything we hear in a film from sound effects and soundtracks to words and background noise. In order for the sound to work within a film, everything must be balanced. This is achieved by splitting the use of sound into 3 categories; Non- Diegetic, Supra Diegetic and Diegetic.

Diegetic sound refers to internal sound (sound from on the set) that we can see on the screen. Dialogue, footsteps, doors slamming etc are all examples of diegetic sound.
Non diegetic sound is simply the opposite (external sound) that is created in a studio.  This includes music, sound effects etc.
Supra Diegetic sound is most commonly used in musicals when there is an orchestra playing and can't be seen on the screen or when the orchestra is shown on screen playing the score.

When was sound first introduced?
One of the biggest milestones in film was the introduction of sound in film. This came in 1926 when Warner Brothers released Don Juan. This was created by an newly introduced sound-disk system which involved music and sound effects being recorded on a wax record that would then be synchronised with the projector.
However. another Warner Brothers film 'The Jazz Singer" (1927) became the first film to have actual sound recorded.