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Impedance Tubes

Impedance Tube - Description:

BSWA SW series Impedance Tubes can accurately measure sound absorption coefficients and impedance according to both ISO and ASTM standards. They also support the sound transmission loss measurements based on the Transfer Function Method. The Transfer Function Method separates the incident and reflected energy from the measured transfer function, and then estimates the acoustic properties of the tested sample installed in the tube.

The SW series Impedance Tubes are specially designed not only to work with the cut samples, but also for direct use in the field. The small size and durable aluminum construction make it easy to be transported and used for estimating the properties of walls, ceilings, installed building materials, road surfaces, different ground surfaces, interiors of vehicles, and etc. BSWA offers the complete set of Impedance Tube system, which includes: the tubes, microphones; DAQ hardware and measurement software.

BSWA 1/4’’ microphones MPA416, which have excellent phase matches, are ideal for impedance applications. The microphones are directly connected to optional 2-channel MC3522 or 4-channel MC3242 data acquisition hardware. PA50 power amplifier is used to drive the loud speaker in the impedance tube. The BSWA VA-Lab software provides all measurement functions for sound absorption and transmission loss testing.

Impedance tube systems for acoustic material testing

Conforms to the following standards:
  • ISO 10534-1: 1996 Acoustics-Determination of sound absorption coefficient and impedance in impedance tubes-Part 1: Method using standing wave ratio.
  • ISO 10534-2: 1998 Acoustics-determination of sound absorption coefficient and impedance in impedance tubes-Part 2: Transfer function method.
  • E 1050-08 Standard test method for impedance and absorption of acoustic materials using a tube, two microphones and digital frequency analysis.
  • E 2611-09 Standard test method for measuring sound transmission at normal incidence of acoustic materials based on the transmission matrix method.

The transmission loss is based on the transfer function method with four microphones, and the ISO standard.
The impedance tube system was developed on BSWA’s digital acquisition hardware with LabVIEW development platform.

Impedance Tube PDF
Impedance tube transport case SW422 and SW477 with 4 MI19 measuring microphones and microphone calibrator CA114
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