1 Scope
This test method covers the use of an impedance tube, two microphone locations and
a digital frequency analysis system for the determination of the sound absorption
coefficient of sound absorbers for normal sound incidence. It can also be applied
for the determination of the acoustical surface impedance or surface admittance of
sound absorbing materials. Since the impedance ratios of a sound absorptive material
are related to its physical properties, such as airflow resistance, porosity, elasticity
and density, measurements described in this test method are useful in basic research
and product development.
The test method is similar to the test method specified in ISO 10534‑1 in that it uses an impedance tube with a sound source connected to one end and the
test sample mounted in the tube at the other end. However, the measurement technique
is different. 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 10534‑1.
Compared with the measurement of the sound absorption in a reverberation room according
to the method specified in ISO 354, there are some characteristic differences. The reverberation room method will (under
ideal conditions) determine the sound absorp...
BS EN ISO 10534-2:2001 history
2023BS EN ISO 10534-2:2023 Acoustics. Determination of acoustic properties in impedance tubes - Two-microphone technique for normal sound absorption coefficient and normal surface impedance
0000 BS EN ISO 10534-2:2001(2002)
1999BS EN ISO 10534-2:2001 Acoustics. Determination of sound absorption coefficient and impedance in impedance tubes - Transfer-function method
1999BS EN ISO 10534-2:1999 Acoustics - Determination of sound absorption coefficient and impedance in impedance tubes - Transfer-function method