Diegetic sound The sound that comes from in the scene E.g. talking, noise of cars, the wind, music from a radio etc An example would be the ‘Psycho’ shower scene, where the only sound heard originally is the diegetic sound of the shower. Later on the sound of the knife used to kill the woman can be heard along with the non-diegetic music. Also, soap operas almost always use diegetic sound.
Non-Diegetic Sound The sound put on a film during post-production E.g. Music soundtrack Sound effects like a crescendo Examples include the Jaws theme during a shark attack and the screeching violins during the Psycho shower scene.
Crescendo Build up of sound or music to imply something is about to happen An example would be in the Godfather when the sound of a train built up until Michael Corleone shoots Soliozzo and Mccluskey in the restaurant.
Diminuendo Where the music or sound dies down, as if a threat has gone away An example would be in the beginning of the episode of CSI ‘Strip Strangler’ when the music builds up as the camera approaches the woman and but dies down after the woman goes back to sleep and the threat is gone.
Sforzando A short, sharp, loud noise, often used to emphasise shock or fear An example would be when the door slams shut and a sforzando plays in Paranormal Activity.