Animation - Effect of Sound Waves on Cochlear Structures

What determines the range of sound frequencies a person can hear?

Sound travels through the air and through water as waves of changing pressure. The volume of a sound is determined by the amplitude of the sound waves, taller waves are louder sounds than shorter waves. The frequency of sound is determined by the wavelength of the sound waves. Short waves are high-pitched sounds, long waves are low-pitched sounds. The cochlea varies in structure so that different wavelengths stimulate different areas in the basilar membrane. Some wavelengths do not stimulate any area of the basilar membrane and are not detectable. In general, smaller ear structures are able to detect higher pitched sounds. Human children are able to hear higher pitched sounds that adults cannot detect. Both cats and dogs are able to hear higher frequency sounds than humans.

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