If you’re lucky, you may someday get a chance to watch a movie whose soundtrack isn’t finished yet. You’ll be scanning channels and stumble across a special about how movies are made, or you’ll see a tribute to a film composer, or you’ll rent a DVD of some movie that includes a “making of” documentary. Such TV shows or DVD’s sometimes include a couple of minutes from the finished movie as it looked before the musical soundtrack and sound effects were added.
At that moment, your understanding of the film medium will take an enormous leap forward. “Jeez,” you’ll say, “without music and sound effects, this $100 million Hollywood film has no more emotional impact than … my home movies!”
And you’ll be right. It’s true that the visual component of film is the most, well, visible. The household names are the directors and movie stars, not the sound editors, composers, foley (sound effects) artists, and others who devote their careers to the audio experience of film.
But without music, sound effects (called SFX for short), and sound editing, even the best Hollywood movie will leave you cold and unimpressed.
— David Pogue, from iMovie ’08 & iDVD, p. 209