The sound we hear results from vibration in the air. The amplitude, or breadth, of vibrations produces our sense of loudness, or volume. Film sound constantly manipulates sound volume. For example, in many films a long shot of a busy street is accompanied by loud traffic noises, but when two people meet and start to speak, the loudness of the noise is characterized as much by the difference in volume as by the substance of the talk.
Loudness is also related to perceived
distance; often the loader the sound, the closer we take it to be. The
couple's dialogue, being louder, is sensed as in the acoustic "foreground",
while the traffic noise sinks to the background.
The frequency of sound vibrations governs pitch, or the perceived "highness" or "lowness" of the sound.
Certain instruments, such as the tuning fork, can produce pure tones, but most sounds, in life and on film, are "complex tones", batches of different frequencies. Nevertheless pitch plays a useful role in picking out distinct sounds in a film sound track. It helps us to distinguish music and speech from other sounds. Pitch also serves to distinguish among objects.
Low-pitched sounds such as thumps, can evoke hollow objects, while higher-pitched sounds (like of fingernails scratching a blackboard) suggest smoother or harder surfaces and more dense objects.
Pitch can also serve more specific purpose in a film. When a young boy tries to speak in a man's deep voice and fails (as in How Green was My Valley) the joke is based primarily on pitch.
When Bernard Hermann obtained the effects
of shrill, birdlike shrieking in Hitchcock's Psycho, even many musicians
could not recognize the source: violins played at extraordinarily
The harmonic components of sound give it a certain "color" or tone quality - what musicians call timbre.
Timbre is actually a less fundamental
acoustic parameter than amplitude or frequency, but it is indispensable
in describing the texture or "feel" of a sound. When we call someone's
voice nasal or certain musical tone mellow, we are referring to timbre.
In everyday life, recognition of familiar sound is largely a matter
of various aspects of timbre.
As fundamental components of film sound, loudness, pitch and timbre interact to define the overall sonic texture of a film. At the most elementary level, these three acoustic factors enable us to distinguish the various sounds in film. For example these qualities enable us to recognize different characters' voices.
Citizen Kane offers a wide range of sound manipulations. Echo chambers alter timbre and volume. The plot's shifts between times and places are covered by continuing dissolves to a shot of crowd applauding (a shift in volume, timbre and pitch)
Art: An Introduction and Film Viewers Guide
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