Larson Davis System 824, Reference Manual

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D-10 824 Reference Manual 11/3/00
unlike band pass filters. It can be composed of one or more
of the following types:
A-Weighting: A filter that adjusts the levels of a frequency
spectrum in the same way the human ear does when exposed
to low levels of sound. This weighting is most often used for
evaluation of environmental sounds. See table below.
B-Weighting: A filter that adjusts the levels of a frequency
spectrum in the same way the human ear does when exposed
to higher levels of sound. This weighting is seldom used.
See table below.
C-Weighting: A filter that adjusts the levels of a frequency
spectrum in the same way the human ear does when exposed
to high levels of sound. This weighting is most often used
for evaluation of equipment sounds. See table below.
Flat-Weighting: A filter that does not adjust the levels of a
frequency spectrum. It is usually an alternative selection for
the frequency-weighting selection.
Center Frequencies, Hz Weighting Network Frequency
Response
1/3 Octave 1 Octave A B C
20 -50.4 -24.2 -6.2
25 -44.7 -20.4 -4.4
31.5 31.5 -39.4 -17.1 -3.0
40 -34.6 -14.2 -2.0
50 -30.2 -11.6 -1.3
63 63 -26.2 -9.3 -0.8
80 -22.5 -7.4 -0.5
100 -19.1 -5.6 -0.3
125 125 -16.1 -4.2 -0.2
160 -13.4 -3.0 -0.1
200 -10.9 -2.0 0