ASA S1.40

Abstract

Sound calibrators generate known sound pressure levels at one or more frequencies in a coupler into which a specified model of microphone is inserted in a specified configuration. <br>NOTE An example of a specified configuration may be with or without a grid. <br>This Standard specifies performance requirements and verification procedures for three classes of coupler-type sound calibrators: <br>&#8212;&#160;Class LS: Laboratory Standard calibrator with the smallest tolerance limits.&#160; <br>&#8212;&#160;Class 1: Sound calibrators that are generally intended for field use with class 1 sound level meters and similar instruments. <br>&#8212; Class 2: Sound calibrators that are generally intended for field use with class 2 sound level meters, dosimeters, and similar instruments. <br>For class LS calibrators, the Standard requires the use of a laboratory standard microphone as specified in ANSI S1.15-1997/Part 1. For class 1 and class 2 calibrators, the Standard requires the use of a working standard microphone as specified in IEC 61094-4:1995. <br>Tolerance limits in this Standard include maximum permitted expanded uncertainties of measurement as well as the tolerance limits allowed for design and manufacturing. <br>This Standard applies to sound calibrators that are used to check or adjust the sensitivity of sound measuring instruments and systems including conventional, integrating-averaging and integrating sound level meters, and personal noise dosimeters. <br>This Standard does not include requirements for the Instruction Manual to provide data for use in adjusting a sound level indicated by a sound level meter, or equivalent instrument, in response to application of a sound calibrator to the equivalent free-field or random-incidence sound level. <br>Sound calibrators may provide two or more sound pressure levels and operate at two or more frequencies. These multiple-level / multiple-frequency calibrators have a single class designation for all combinations of levels and frequencies for which the Instruction Manual states conformance to the requirements of this Standard. <br>Additional useful functions such as tonebursts may be provided. Requirements for these additional functions are not included in this Standard.