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11.1 Fundamentals of Sound
11.1.1 Introduction
Noise is referred to as unwanted sound; it is a common
by-product of our mechanized civilization and is an
insidious danger in industrial environments. Consi-
dering the impact on people, noise is most often a source
of annoyance, but it can also have more detrimental
effects, such as causing physical injury. Noise-related
injuries range from short-term discomfort to perma-
nent hearing loss. According to recent statistics, more
than 20 million Americans are exposed to hazardous
sound levels on a regular basis. There are approximately
28million Americans who have some degree of hearing
loss: abo ...