ASTM E1050-12
Standard Test Method for Impedance and Absorption of Acoustical Materials Using a Tube, Two Microphones and a Digital Frequency Analysis System

Standard No.

ASTM E1050-12

Release Date

2012

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E1050-19

Latest

ASTM E1050-19

Scope

This test method can be applied to measure sound absorption coefficients of absorptive materials at normal incidence, that is, 0°. It also can be used to determine specific impedance and admittance ratios. The properties measured with this test method are useful in basic research and product development of sound absorptive materials.

Normal incidence sound absorption coefficients can be quite useful in certain situations where the material is placed within a small acoustical cavity close to a sound source, for example a closely-fitted machine enclosure.

This test method allows one to compare relative values of sound absorption when it is impractical to procure large samples for accurate random-incidence measurements in a reverberation room. Estimates of the random incidence absorption coefficients can be obtained from normal impedance data for locally-reacting materials (2).

Note 28212;The classification, “locally-reacting” includes fibrous materials having high internal losses. Formulas have been developed for converting sound absorption properties from normal incidence to random incidence, for both locally-reacting and bulk-reacing materials (3).

Measurements described in this test method can be made with high precision, but these measurements may be misleading. Uncertainties of greater magnitude than those from the measurements may occur from other sources. Care should be exercised to sample nonuniform materials adequately (see 11.1).

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

1.2 Laboratory Accreditation8212;A procedure for accrediting a laboratory for performing this test method is given in Annex A1.

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the use of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

ASTM E1050-12 Referenced Document

• ANSI/ASA S1.11 Specification for Octave-Band and Fractional-Octave-Band Analog and Digital Filters
• ASTM C384 Standard Test Method for Impedance and Absorption of Acoustical Materials by the Impedance Tube Method
• ASTM C634 Standard Terminology Relating to Building and Environmental Acoustics
• ASTM E548 
• ISO 10534-1 Acoustics - Determination of sound absorption coefficient and impedance in impedance tubes - Part 1: Method using standing wave ratio

ASTM E1050-12 history

• 2019 ASTM E1050-19 Standard Test Method for Impedance and Absorption of Acoustical Materials Using A Tube, Two Microphones and A Digital Frequency Analysis System
• 2012 ASTM E1050-12 Standard Test Method for Impedance and Absorption of Acoustical Materials Using a Tube, Two Microphones and a Digital Frequency Analysis System
• 2010 ASTM E1050-10 Standard Test Method for Impedance and Absorption of Acoustical Materials Using A Tube, Two Microphones and A Digital Frequency Analysis System
• 2008 ASTM E1050-08 Standard Test Method for Impedance and Absorption of Acoustical Materials Using A Tube, Two Microphones and A Digital Frequency Analysis System
• 2007 ASTM E1050-07 Standard Test Method for Impedance and Absorption of Acoustical Materials Using A Tube, Two Microphones and A Digital Frequency Analysis System
• 1998 ASTM E1050-98(2006) Standard Test Method for Impedance and Absorption of Acoustical Materials Using A Tube, Two Microphones and A Digital Frequency Analysis System
• 1998 ASTM E1050-98 Standard Test Method for Impedance and Absorption of Acoustical Materials Using a Tube, Two Microphones, and a Digital Frequency Analysis System