Non-Pitched Atmospheric Sounds

Non-Pitched Atmospheric Sounds

Non-pitched atmospheric sounds are used in film making to create a similar feeling to what the score tries to establish, but in a more subtle fashion. They aren't usually very noticable unless you're looking for them, but will still have the effect regardless of if you're aware of a sound being played.

A brilliant example of the effectiveness of atmospheric sounds is Orin Peli's "Paranormal Activity". Often throughout the film, when there is a silence, an extremely low rumble is used to create subtle suspense and a feeling of uneasiness in the viewer.

Note how the extremely low frequency sound stops as soon as the door slams shut. The sound is used to build suspense, to make the viewer aware that something is going to happen. This is very effective on high end sound systems such as those in cinemas where the subwoofers can produce extremely low sounds. Found footage movies like this generally have no score or non-diegetic sounds, so these techniques are usually relied on to keep it subtle and make it feel more realistic than high-budget blockbuster.