Sound effects (or audio effects) are artificially created or enhanced sounds, or sound processes used to emphasize artistic or other content of films, television shows, live performance, animation, video games, music, or other media. In motion picture and television production, a sound effect is a sound recorded and presented to make a specific storytelling or creative point without the use of dialogue or music. The term often refers to a process applied to a recording, without necessarily referring to the recording itself. In professional motion picture and television production, dialogue, music, and sound effects recordings are treated as separate elements. Dialogue and music recordings are never referred to as sound effects, even though the processes applied to such as reverberation or flanging effects, often are called "sound effects".
The term sound effect ranges back to the early days of radio. In its Year Book 1931 the BBC published a major article about "The Use of Sound Effects". It considers sounds effect deeply linked with broadcasting and states: "It would be a great mistake to think of them as anologous to punctuation marks and accents in print. They should never be inserted into a programme already existing. The author of a broadcast play or broadcast construction ought to have used Sound Effects as bricks with which to build, treating them as of equal value with speech and music." It lists six "totally different primary genres of Sound Effect":
According to the author, "It is axiomatic that every Sound Effect, to whatever category it belongs, must register in the listener's mind instantaneously. If it fails to do so its presence could not be justified."
In the context of motion pictures and television, sound effects refers to an entire hierarchy of sound elements, whose production encompasses many different disciplines, including:
Each of these sound effect categories is specialized, with sound editors known as specialists in an area of sound effects (e.g. a "Car cutter" or "Guns cutter").
Foley is another method of adding sound effects. Foley is more of a technique for creating sound effects than a type of sound effect, but it is often used for creating the incidental real world sounds that are very specific to what is going on onscreen, such as footsteps. With this technique the action onscreen is essentially recreated to try to match it as closely as possible. If done correctly it is very hard for audiences to tell what sounds were added and what sounds were originally recorded (location sound).