Page 66 - The Master Handbook Of Acoustics

CHAPTER
3

The Ear and the

Perception of Sound

he study of the structure of the ear is a study in physiology. The
Tstudy of human perception of sound comes under the general head-
ing of psychology. Psychoacoustics is an inclusive term embracing the
physical structure of the ear, the sound pathways, the perception of
sound, and their interrelationships. Psychoacoustics, quite a recent
term, is especially pertinent to this study because it emphasizes both
structure and function of the human ear.
The stimulus sound wave striking the ear sets in motion mechani-
cal movements that result in neuron discharges that find their way to
the brain and create a sensation. Then comes the question, “How are
these sounds recognized and interpreted?” In spite of vigorous
research activities on all aspects of human hearing, our knowledge is
still woefully incomplete.

Sensitivity of the Ear

The delicate and sensitive nature of our hearing can be underscored dra-
matically by a little experiment. A bulky door of an anechoic chamber is
slowly opened, revealing extremely thick walls, and three-foot wedges of
glass fiber, points inward, lining all walls, ceiling, and what could be
called the floor, except that you walk on an open steel grillwork.
A chair is brought in, and you sit down. This experiment takes time,
and as a result of prior briefing, you lean back, patiently counting
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