ASA - ANSI/ASA S1.40
AMERICAN NATIONAL STANDARD Specifications and Verification Procedures for Sound Calibrators
|Publication Date:||20 September 2006|
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.
NOTE An example of a specified configuration may be with or without a grid.
This Standard specifies performance requirements and verification procedures for three classes of coupler-type sound calibrators:
⎯ Class LS: Laboratory Standard calibrator with the smallest tolerance limits.
⎯ Class 1: Sound calibrators that are generally intended for field use with class 1 sound level meters and similar instruments.
⎯ Class 2: Sound calibrators that are generally intended for field use with class 2 sound level meters, dosimeters, and similar instruments.
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.
Tolerance limits in this Standard include maximum permitted expanded uncertainties of measurement as well as the tolerance limits allowed for design and manufacturing.
This Standard applies to sound calibrators that are used to check or adjust the sensitivity of sound measuring instruments and systems including conventional, integrating-averagin
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.
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.
Additional useful functions such as tonebursts may be provided. Requirements for these additional functions are not included in this Standard.