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Unwanted sound. Noise control is the process of obtaining an acceptable noise environment for people in different situations. Understanding noise and its control requires a knowledge of the major sources of noise, sound propagation, human response to noise, and the physics of methods of controlling noise. The continuing increase in noise levels from many different human activities in industrialized societies has led to the term noise pollution.
Noise as an unwanted by-product of an industrialized society affects not only the operators of machines and vehicles, but also other occupants of buildings in which machines are installed, passengers of vehicles, and most importantly the communities in which machines, factories, and vehicles are operated.
