Simple measurements of sound magnitude
cannot deal with all of the environmental and communicational
factors encountered in noise problems wherever they occur.
Specialized measurement and evaluation systems have had to be
developed which take a variety of additional factors into account,
such as the frequency content and time-dependence of the noise,
interference with speech communication, criteria for indoor
environments intended for certain activities, evaluation of
specific noise sources such as traffic and aircraft, establishing
overall community noise impact, and so on.
In most cases, the pattern is to quantify the
noise and correlate it to individual or community reaction,
usually with the aim of establishing "acceptable" or "recommended"
levels, or in some cases, in order to predict the impact of higher
noise levels. The criteria arrived at are often used by various
levels of government in establishing by-laws, standards and
guidelines for noise control and abatement.
The specific case of damage-risk criteria for
hearing protection in industry is considered under the larger
topic of Audiology
and Hearing Loss. Other noise
measurement systems are presented here under the following general
A) Basic measurement systems: a
review of common "level" measurements;
B) Speech communication
C) Indoor environment
D) Aircraft and Traffic measurement
systems and their correlation to public annoyance;
E) Community noise evaluation
F) Measurement of absorption,
reflection and transmission properties of materials as
criteria for sound insulation.