ISO(1053-2) download impedance tube

Check out our FAQs. Buy this standard. This standard was last reviewed and confirmed in Therefore this version remains current. Abstract Preview Specifies a method for the determination of the sound absorption coefficient, reflection factor, surface impedance or admittance of materials and objects.

Status : Published. Publication date : In this test method, plane waves are generated in a tube by a noise source, and the decomposition of the interference field is achieved by the measurement of acoustic pressures at two fixed locations using wall-mounted microphones or an in-tube traversing microphone, and subsequent calculation of the complex acoustic transfer function, the normal incidence absorption and the impedance ratios of the acoustic material.

The test method is intended to provide an alternative, and generally much faster, measurement technique than that of ISO Compared with the measurement of the sound absorption in a reverberation room according to the method specified in ISO , there are some characteristic differences. The reverberation room method will under ideal conditions determine the sound absorption coefficient for diffuse sound incidence, and the method can be used for testing of materials with pronounced structures in the lateral and normal directions.

However, the reverberation room method requires test specimens which are rather large, so it is not convenient for research and development work, where only small samples of the absorber are available. The impedance tube method is limited to parametric studies at normal incidence but requires samples of the test object which are of the same size as the cross-section of the impedance tube.

For materials that are locally reacting, diffuse incidence sound absorption coefficients can be estimated from measurement results obtained by the impedance tube method. For transformation of the test results from the impedance tube method normal incidence to diffuse sound incidence, see annex F.

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