Certification and Registration
GB/T 18696.1: Acoustics — Measurement of sound absorption coefficient and specific acoustic impedance in impedance tubes — Standing wave ratio method
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Chinese
ISO 10534-1 (GB/T 18696.1) Standard Description
ISO 10534-1 Acoustics - Determination of sound absorption coefficient and impedance in impedance tubes - Part 1: Method using standing wave ratio
GB/T 18696.1 Acoustics—Determination of sound absorption coefficient and impedance in impedance tubes—Part 1: Method using standing wave ratio
ISO 10534-1 (GB/T 18696.1) Standard Introduction
ISO 10534-1 (GB/T 18696.1) specifies a method for determining the sound absorption coefficient, reflection coefficient, surface impedance, or admittance of materials and objects using the standing wave ratio method. It is applicable for measuring the sound absorption performance of materials under normal incidence sound waves.This method requires the use of an impedance tube (Kundt tube), where standing waves are generated by the superposition of incident and reflected sinusoidal plane waves. Acoustic characteristic parameters are then calculated based on the measured standing wave pattern.ISO 10534-1 (GB/T 18696.1) is particularly suitable for research and development stages and laboratory environments, providing accurate sound absorption parameters and data support for noise control and acoustic material design.
ISO 10534-1 (GB/T 18696.1) Scope of Application
ISO 10534-1 (GB/T 18696.1) applies to the measurement of sound absorption performance of various materials and structures under normal incidence sound conditions, including the following products and applications:
◎ Wall and ceiling acoustic panels (such as mineral wool panels and wood wool acoustic panels)
◎ Sound insulation doors and windows (for evaluating material sound absorption performance)
◎ Foam materials (such as polyurethane foam and polyethylene foam)
◎ Porous sound absorbing materials (glass wool, rock wool, aluminum foam)
◎ Perforated panels (metal or wooden panels with small holes)
◎ Micro-perforated panels (metal or plastic panels with smaller perforations)
◎ Composite sound absorbing structures (such as honeycomb sandwich structures)
ISO 10534-1 (GB/T 18696.1) Test equipment
◎ Impedance Tube: A cylindrical tube with a diameter suitable for the required frequency range.
◎ Loudspeaker: Installed at one end of the tube to generate plane sound waves.
◎ Test specimen: Installed at the opposite end of the impedance tube.
◎ Standing wave detection system: A movable measurement microphone or a standing wave ratio meter (for manual measurements).
◎ Signal generator: Provides sinusoidal signals.
◎ Analysis system: Calculates the standing wave ratio and determines the sound absorption coefficient and acoustic impedance.
ISO 10534-1 (GB/T 18696.1) Test Method
Specimen preparation: Select a material specimen with suitable dimensions. The specimen diameter is generally required to be equal to the inner diameter of the impedance tube.
Generation of plane sound waves: A loudspeaker is installed at the open end of the impedance tube to generate sinusoidal waves inside the tube. The selected frequencies shall cover the required test range.
Measurement of standing wave ratio: When sound waves are reflected from the specimen surface, the reflected waves combine with the incident waves to form standing waves. A movable microphone or standing wave ratio meter is used to measure sound pressure at different positions inside the tube.
The maximum sound pressure (Pmax) and minimum sound pressure (Pmin) of the standing wave are calculated to obtain the standing wave ratio:
ISO 10534-1 (GB/T 18696.1) Evaluation Criteria
Calculation of acoustic parameters:
(1) Reflection coefficient R:
(2) Calculation of sound absorption coefficient α:
(3) Calculation of surface impedance Zs:
Z0 is the characteristic impedance of air.
More standards related to impedance tubes
ISO 10534 Acoustics — Determination of sound absorption coefficient and impedance in impedance tubes
ISO 10534-2 Measurement of sound absorption coefficient and acoustic impedance in impedance tubes (Transfer-function method)
GB/T 18696.1 Measurement of sound absorption coefficient and acoustic impedance of materials (Standing wave ratio method)
GB/T 18696.2 Measurement of sound absorption coefficient and acoustic impedance of materials (Transfer-function method)
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