2444, rue Bonin Sherbrooke, J1K 1C4, Canada

(819) 346-5666 info@mecanum.com

Impedance and Transmission Tube Using 4 Microphones


Mecanum’s 4 microphones impedance tubes are specifically designed to measure the main normal indicators of a wide range of acoustical materials. The method is based on ASTM E1050ISO 10534-2 and ASTM E2611 standards for the absorption coefficient (α), the reflection coefficient (R) and the surface impedance (Zs). All other parameters are determined using the 4 microphones technique (ASTM E2611) or the 3 microphones technique12.

Note: All 4 microphones tubes also comes with the 3 microphones technique, in other words, all the latest techniques and standards are gathered in this high-end equipment.


**   Large spacing between µ1 and µ2 (or µ3 and µ4) is essential for better results at low frequencies (as stated in ASTM E1050)


Material properties

➡ Normal incidence sound absorption coefficient (α)

➡ Normal incidence complex reflection coefficient (R)

➡ Normal surface impedance (Zs/Zair)

➡ Normal incidence sound transmission loss (TL)

➡ Characteristic impedance (Z/Zair)

➡ Wave number (k)

➡ Transfer matrix coefficients (Tij)

➡ Equivalent/effective dynamic density (ρeq)

➡ Equivalent/effective dynamic bulk modulus or compressibility (Keq)


Tube Internal Diameter Frequency Range
29 mm  200-6600 Hz
44.44 mm 100-4300 Hz
 100 mm  35-1900 Hz


TUBE-X is a user-friendly software that will simplify your measurement procedure. It will allow you to choose between the different measurement techniques. It’s also fully compatible with FOAM-X software that can extract non-acoustic parameters of porous materials using the inverse method with a 2, 3 or 4 microphones absorption measurement and indirect method using the 3 or 4 microphones measurement.


  • Every Mecanum impedance tube is supplied with grids (for samples with low mechanical strength) and rings (to avoid leaks).

Main advantages of the product

Measurement method in accordance with the ASTM and ISO standards;

User-friendly interface;

Measurement method from the scientific literature;

Superior manufacturing quality.

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