1.1 This test method covers the use of an impedance tube and the use of a two-microphone method and a digital frequency analysis system for the measurement of normal incidence sound absorption coefficients and normal specific acoustic impedance ratios of materials.

1.2 This standard does not purport to address the safety problems associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.