PSYC 369 Chapter Notes - Chapter 11: Sound Pressure, Vestibular Duct, Tectorial Membrane
10 Dec 2013
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Chapter 11: sound, the auditory system, and pitch perception. Physical definition - sound is pressure changes in the air or other medium. Perceptual definition - sound is the experience we have when we hear. The diaphragm of the speaker moves out, pushing air molecules together called condensation. The diaphragm also moves in, pulling the air molecules apart called rarefication. The cycle of this process creates alternating high- and low-pressure regions that travel through the air: pure tone - created by a sine wave. Amplitude - difference in pressure between high and low peaks of wave: perception of amplitude is loudness, decibel (db) is used as the measure of loudness, number of db = 20 logarithm(p/po) The decibel scale relates the amplitude of the stimulus with the psychological experience of loudness: p is the sound pressure of the stimulus, and po is the standard sound pressure which is usually set at 20 micropascals.
