Have you ever heard of silent movies? If you think they are movies where actors do not talk, you guessed wrong. Technically, the actors could speak; you could see their lips moving and, for any good lip reader, it wasn't hard to interpret what they were saying. For everyone else, it was the addition of onscreen intertitles that finally helped point out key aspects of the dialogue or comment on the action for the cinema audience.
Silent films even commonly featured music, which essentially contributed to the atmosphere of the movie (romance, action, sadness, etc) and gave the audience critical emotional cues on top of facial expressions and body language. So although there was no synchronized recorded sound (audible spoken dialogue, for example) in those silent movies, they were never really mute.
Today's movies though are chalked full of sounds. Other than the soundtrack, there is a whole range of other sounds, from explosions to bone-breaking blows that are incredibly powerful and realistic (even though I have never witnessed an explosion in my life, they sound pretty convincing to me in the movies).
But many of these sounds are not au naturale—most of the time, they are recorded by foley artists and recording engineers in studios. This is most obvious for animated movies, like the recent Ratatouille where producers needed the sounds of a restaurant kitchen.
According to Philip Rodriguez' (a foley artist) website: "On a film set nothing is real: the sword is made of plastic, the marble floor is painted plywood. Foley replaces or enhances that live sound and the result is a sword that rings like metal and floors that echo like marble."
Did you know? Hitting meat slabs with chains and frying pans was used to create punch sounds in some of Silvester Stalone's Rocky films.
Nothing is real seems right when you consider that many of the sounds you hear in movies can be created from simple daily objects. For example, corn starch in a leather pouch can be used to create the sound of snow crunching, a pair of gloves are used to make sounds like bird's wings flapping, a heavy staple gun and other metal parts can make a realistic gun sound, while cellophane makes an excellent prop for creating the sound of crackling fire!
Rodiguez goes on to say that "besides, during filming, the location sound recordist tries to capture only the dialogue. Microphones are keenly positioned on set to record even an actor's slightest whisper without the background noises from camera and crew. Foley helps to add back in that layer of sound to produce a rich and realistic track."
Did you know? There are exceptions for capturing dialogue: For R2-D2's voice in Star Wars, 50 % of the droid´s voice was made electronically. The rest is a combination and blending of water pipes, whistles, and vocalizations by sound designer Ben Burtt.
The enthusiasm of sound engineering technicians and foleys is such that they are always at risk of producing some oddities. For example, have you ever heard the sound of a knife touching another metallic object when it's just been pulled from a leather sheath? Or what about the classical noisy explosions that one can hear in space (insider information: mechanical wave sounds cannot travel in the space vacuum)... well, I guess nobody is perfect.
So next time you go to the movies, it might be interesting to pay attention to the sound effects—or the absence of them—and the possible reactions of the audience to them (i.e., how and why the sound were produced). However, do not take the fun out of it: try to relax and enjoy the show... it's just a movie.
Art of Film Sound Design
Hollywood Sound Effects
The Art of Foley
Giuliano Reis is currently an assistant professor of science education at the University of Ottawa. He is also interested in environmental education and teacher education. He was a science teacher in Brazil from 1996-2003 before moving to Canada.