Square impedance tube

Square impedance tube
ASTM E1050
ASTM E2611
ISO 10534-2
38.1 & 100 mm

Ideal for measuring normal-incidence sound absorption and transmission loss of square samples such as acoustic metamaterials.

Mecanum’s square impedance and transmission tube measures the key acoustic indicators of a wide range of materials using 2 or 4 microphone methods. Available in 38.1 mm and 100 mm, it is purpose-built for acoustic metamaterials such as sonic crystals: its parallel walls create the infinite reflections that reproduce a network of unit cells, and its sample holder, with three transparent sides and a movable top, makes inserting and reconfiguring samples fast and clear. It follows ASTM E1050, ASTM E2611, and ISO 10534-2.

Performance

Frequency range

38.1 mm tube: 45 Hz to 4300 Hz
100 mm tube: 35 Hz to 1600 Hz

Hard wall measurement (zero absorption)

All ⅓ octave until 4 kHz < 4 %
⅓ octave 5 kHz and above < 10 %

Dimensions & sample thickness

Dimensions

38.1 mm tube: 1400 (L) x 110 (W) x 240 (H) mm
100 mm tube: 1800 (L) x 160 (W) x 240 (H) mm

Max sample thickness

2 microphones: 200 mm
4 microphones: 200 mm

Measured properties

4 mics4
2 mics2
Absorption coefficient at normal incidence (α)Absorption (α)
Complex reflection coefficient at normal incidence (R)Reflection (R)
Normalized surface impedance (Zs/Zair)Surface impedance (Zs/Zair)
Normal incidence transmission loss (NSTL)Transmission loss (NSTL)
Normalized characteristic impedance (Z/Zair)Charact. impedance (Z/Zair)
Wave number (k)Wave number (k)
Equivalent dynamic bulk density (ρeq)Bulk density (ρeq)
Equivalent dynamic bulk modulus (Keq)Bulk modulus (Keq)
Transfer matrix coefficients (Tij)Transfer matrix (Tij)
ASTM E1050ASTM E1050
ISO 10534-2ISO 10534-2
ASTM E2611ASTM E2611

Tube-X

Tube-X guides you through normal-incidence absorption and transmission loss measurement in a single, intuitive window, clear enough to be productive from the first use. It supports all 2, 3, and 4 microphone methods alongside advanced research features, and lets you save raw data to run your own post-processing. Built-in tools take measurements further, averaging, smoothing, merging curves across frequency ranges, adding an air cavity, comparing projects, and a one-click, ISO/ASTM-ready Excel report turns results into professional documentation.

On the square impedance tube, Tube-X keeps the same clear workflow but is oriented specifically toward square samples and metamaterial testing, so the same easy interface carries you through non-conventional geometries.

Coming soon.

Automotive industry

Test lightweight noise-control materials and metamaterial concepts at normal incidence for cabin and component design.

Aerospace industry

Characterize metamaterial absorbers, and evaluate engine or silencer liners under grazing incidence.

Material manufacturers

Characterize non-conventional geometries and metamaterials that circular tubes cannot accommodate.

Building

Screen porous absorbers and multilayer materials on larger square samples before full-scale testing.

Laboratories

Run standards-compliant absorption and transmission loss measurements on square and metamaterial samples.

Universities

Explore sonic crystals and metamaterials with a clear-view sample holder built for fast reconfiguration.

Optional accessories, available with your square impedance tube or separately.

Grazing incidence sample holder

With the grazing incidence sample holder, the impedance tube evaluates liner performance under grazing conditions that mirror real operating environments. Using the four-microphone transfer matrix method, it derives impedance and transmission loss for aircraft engine liners, muffler coatings, and pipe treatments.

Square impedance tube
ASTM E1050
ASTM E2611
ISO 10534-2
29, 44.4, 100 mm

Ideal for measuring normal-incidence sound absorption and transmission loss of square samples such as acoustic metamaterials.

Square impedance tube

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