In audiovisual narration, sound can be analyzed in two categories:
- diegetic
- non-diegetic or extra-diegetic
We speak of diegetic sound when the sound source is in the filmic space , that is, it belongs to history . The main requirement of diegetic sound is to be realistic and consistent with dramatic space. The voice of the characters, the music from a radio, the sound of a door, etc. they are diegetic sounds. On the other hand, non-diegetic sound does not belong to the physical space , that is, it does not concern history. The soundtrack and the voice of a narrator are clear examples of non-diegetic sound.
In general, diegetic sound is that sound perceived by the characters; and the non-diegetic is the one that is not perceived. However, according to Chion, there is the subjective diegetic sound that corresponds to what the characters imagine and hear inside, it is the inner voice . We must understand that, although it is not perceived by the other characters, it is perceived by the character that thinks.
Although extradiegetic sound is often used as a dramatic resource, some directors like Gus Van Sant use diegetic sound precisely to accentuate drama and tension. A clear example is the Elephant (2003), where the diegetic sound dominates the whole story. Even the moment before the massacre, the music we listen to comes from the piano of one of the main characters.
Let’s also not forget one of the most controversial European directors, Lars von Trier . In his film Los idiotas (1998) , and in coherence with the «norms» established in Dogma 95, diegetic sound is of enormous importance. On the one hand, this sound accentuates the realism of the story -again in keeping with Dogma 95-; on the other hand, it highlights the drama of the story.
