NTi Audio XL2 Sound Level Meter - Manual (Page 108)

108
Noise Curves
Preferred Noise Criteria PNC
(in accordance with ASA 1971)
PNC curves represent a more stringent method based on an
extension of the basic Noise Criteria system. They have been
used in the past to judge the acceptability of ventilation and
other background broadband noise. PNC curves are less often
used than Noise Criteria curves because they are more strin-
gent at lower frequencies than the Noise Criteria curves, but
also because the latest (2008) version of Noise Criteria curves
also includes an extended frequency range somewhat mitigat-
ing the original reasons for PNC.
Noise Curves Result Page
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