Rhythm
The first major feature of film sound is rhythm. Rhythm holds a beat, pace or tempo and it is most recognizable in music rather than other diegetic and non-diegetic sounds. For example:
In this scene, the Jaws theme plays and gradually increases in tempo as Jaws gets closer to its victim. This has a recognizable rhythm that progressively gets faster and in turn, builds tension. However, rhythm is not only featured in music, it is also heavily used in dialogue, particularly speeches. For example, this scene from Independence day features the President making a speech; the actor speaks in a rhythm that keeps the audience captivated as it is not one, long, monotone speech with no pauses. The pauses in the speech actively add to the rhythm, making the speech much more captivating.
Fidelity
Fidelity of sound is also a hugely important aspect of sound in movies. Fidelity is how faithful a sound is to its 'supposed' source. For example, if the movie shows a gun being fired, it should be accompanied by the sound of a gun being fired. However, lack of fidelity is sometimes used on purpose whilst still being able to add to the movie. For example, in war movies, techniques are often used that have an explosion go off which creates a loud ringing sound. This ringing sound then consumes any other sound onscreen, this cleverly puts the viewer into the mind of the characters on screen as the viewer is able to tell that the character cannot hear anything even though there should clearly be other types of sound in the background.
Contrapuntal and Parallel sound
Parallel sound is where a sound matches what is happening on screen (in both physicality and tone) similar to the Jaws video.
However, Contrapuntal sound is where the sound does not match what is happening on screen and therefore gives off a completely different feel and tone for the viewer. For example, this scene from Reservoir Dogs, where a character is being tortured, but the music playing is completely opposite to the tone of the scene, this is very jarring to the viewer, which makes them feel especially uncomfortable.
Synchronous and Asynchronous sound
Synchronous sound is simply where the sound matches up with what is happening on screen, for example, dialogue between two characters where the sound is synced with their lips moving.
However, asynchronous sound is deliberately out of sync with the video. This can be used (and is often used) in things like flashbacks as it creates a much more dramatic and eerie tone for the viewer.
Volume
Volume is how loud a quiet the sound within a scene is. Sudden and dramatic changes in volume are often used in horror films to scare the viewer. For example, this scene from Alfred Hitchcock's Psycho, features a very sudden change in volume and pitch which is used to scare the viewer . This use of sound is especially effective as there is a long stretch in which the film is very quiet, which builds tension.





