person with very good hearing in an extremely quiet environment. To use the decibel in
a familiar example, the sound pressure level in a large administrative office is usually
between 40 and 60 dB. It should be no higher than 60 dB.
m. The dB(A). When measuring the intensity of sound using a sound level
meter, the meter is equipped with a system of "weighting networks" whose effect is to
duplicate the response of the human ear. To achieve this, these weighting networks
cause the sensitivity of the meter to vary with frequency and intensity of sound, as does
the sensitivity of the human ear. When referring to sound levels in this subcourse, we
will be referring to sound levels measured by a meter employing the "A-weighting"
network and will use the term "dB(A)" rather than "dB." Table 3-1 lists some typical
noise levels, given in dB(A).
n. The dB(P). This is the unit used to express the peak sound pressure of
Table 3-1. Some typical noise levels.