Sound Absorption Coefficient Testing
Sound Absorption Testing
Impedance tube + AFD software + Multi-channel instrument by SINUS Messtechnik GmbH
The impedance tube AFD 1000 – AcoustiTube® measurement system determines the sound absorption and reflection coefficients, as well as the impedance ratio, of material samples in a laboratory based on the DIN EN ISO 10534-2 transfer-factor method.
The measurement results allow direct determination of the rated sound absorption coefficient of a sample according to DIN EN ISO 11654.
AcoustiTube is based on a measurement technique in which a plane sound wave is emitted towards a sound-absorbing material sample in front of a reverberant termination within the impedance tube. The resulting sound pressure is measured by two microphones in front of the sample. The two microphones are connected to a multi-channel instrument, such as the Soundbook, Noise PAD, Expander/Apollo/Apollo Lite Box (plus laptop) by SINUS Messtechnik GmbH. The AFD software is used to communicate with the acquisition device and perform the measurements.
Depending on the application field different sample holders are available.
Sample holder I
Application field: Determination of the sound absorption coefficient in a laboratory according to DIN EN ISO 10534-2.
Samples: Cylindrical samples with a diameter of 15mm, 30mm, 40mm or 100mm.
Application: Mounting and soundproof sealing of prepared cylindrical samples of variable thickness on continuously adjustable and lockable sample holder.
Sample holder II
Application field: In-situ determination of the sound absorption coefficient according to DIN ISO 13472-2 (sound absorption coefficient < 0.15).
For samples of road surfaces and plate-shaped samples with minimum dimensions of 300mm x 300mm
Adapter for soundproof attachment of the impedance tube to a sample surface.
Compression sample holder
The compression sample holder is an extension to the impedance and transmission tubes. It is almost continuously adjustable in length. Furthermore the compression sample holder allows defined compression of cylindrical samples or bulk sample material for determination of the sound absorption coefficient. Finally it facilitates controlled installation of thin materials
AFD 1000.1 Impedance Tube Software
The AFD 1000 software is a comprehensive, high-performance engineering tool for the frequency-dependent determination of material characteristics. AFD 1000 enables the averaging of results from different material samples, to easily manage and compare results using a database and to determine the sound absorption and reflection coefficients as well as the impedance ratio of test objects in the laboratory based on the DIN EN ISO 10534-2 transfer-factor method.
AFD 3001 – Acoustic Design of Multi-Layer Systems (802054.0)
In addition, the AFD 3001 software allows the acoustic design of multilayer systems by means of a graphical user interface.
- environmental conditions
- thickness of material setup
- material parameters, e. g. length-related airflow resistance; tortuosity; structure factor; porosity calculation models / measured data: Air and open porous absorbers. Model according to DELANY-BAZELY; model of homogeneous medium; phenomenological model; complex absorber values measured in the transmission tube (continuous spectrum)
General technical specifications of AcoustiTube
15mm impedance tube
Inner diameter 15mm
Frequency range 150 … 10200Hz
30mm impedance tube
Inner diameter 30mm
Frequency range 150 … 6600Hz
40mm impedance tube
Inner diameter 40mm
Frequency range 100 … 4400Hz
100mm impedance tube
Inner diameter 100mm
Frequency range 50 … 2000Hz
AFD 1000 260mm
AFD 1200 80mm
Compression sample holder 170mm