ANSI/ASA S1.43-1997 (R2007): Specifications for Integrating-Averaging Sound Level Meters

This standard conforms closely to the IEC Standard for Sound Level Meters, Publication 651, First Edition issued in 1979. This revision represents a significant improvement over ANSI S1.4-1971, particularly in its specifications relating to measurement of transient sound signals. It also permits the use of digital techniques and displays. The principal changes from ANSI S1.4-1971 are: inclusion of an optional impulse exponential-time averaging characteristic; inclusion of an optional peak characteristic; more rigorous definition of the dynamic characteristics for the Fast and Slow exponential-time-averaging; increase in the crest factor requirement to ten for type 1 instruments; specification of a type 0 laboratory instrument with generally smaller tolerance limits than those previously specified for type 1; and deletion of the type 3 survey instrument.

The ANSI/ASA S1.42 2001 (R2011) standard provides the design criteria for both the frequency-domain response (amplitude and phase) and time-domain response of the A-, B-, and C-weighting networks used in acoustically related measurements. The poles and zeros for each weighting network are given, along with equations for computing the amplitude and phase responses as functions of frequency and the impulse and step responses as functions of time. In the Appendix, similar information is provided for the D- and E-weighting networks. The aim is to examine the design goal specifications of weighting networks for acoustical measurements. The scope is restricted to the design, or target, responses of weighting networks. Tolerances that belong in the instrument performance specifications are not included.