µZ impedance tube

Introduction

µZ (pronounced: /'mju:zi:/) is a state-of-the-art impedance tube designed for precise acoustic testing of small material samples. The device gets it name from the symbols for micro (µ) and impedance (Z). It can be used to measure the acoustic properties of small material samples, like meshes, membranes, or vents, typically used in hearables. µZ operates effectively over a wide frequency range, depending on the specific type of device.

Use-cases

Although it is designed to measure acoustic properties of thin samples, µZ can also be used for regular impedance tube measurements. Combined with the ACME measurement and analysis software, the system can be used for:

• Acoustic material characterization: Characterization of the series impedance of thin materials such as meshes and membranes.
• Sound absorption measurements: Evaluation of the normal incidence sound absorption and reflection coefficient of an acoustic sample.
• Quality control: Monitoring acoustic products to ensure consistent quality.

General measurement procedure outline

Usage of the µZ system consists of the following steps:

1. Measurement configuration: Decide whether to use the 4 or 5 microphone method and (in case of the 5 microphone method) pick a cavity size.
2. Setup: Connect the hardware and set a DAQ configuration in the ACME software.
3. Calibration: Determine system and environmental parameters to ensure accurate measurement results.
4. Reference measurement (optional): Measure the impedance of an empty sample holder, so it can be (automatically) corrected for in the analysis phase.
5. Sample measurement: Measure the impedance of a sample, including its sample holder.
6. Analysis: Plot various acoustic properties of the sample, as a function of frequency.