Technical & Applied Article

FOAM 02: A dataset of impedance tube measurements with different materials and diameter variations

¹ PASTA LAB – Laboratory for Promoting Experiences in Aeronautical Structures and Acoustics, University “Federico II” of Naples, Naples, 80125, Italy
² Institute of Fundamentals and Theory in Electrical Engineering (IGTE), Graz University of Technology, Inffeldgasse 18/I, 8010 Graz, Austria
³ Faculty of Mechanical Engineering, Kiel University of Applied Sciences, Grenzstraße 3, 24149 Kiel, Germany

^* Corresponding author: kraxberger@tugraz.at

Received: 11 December 2024
Accepted: 2 July 2025

Abstract

Impedance tube measurements are a widespread method for determining the sound absorption coefficient (SAC) of porous materials for normal sound incidence. The measurement method is standardised in ISO 10534-2. However, the standards offer limited guidance on sample preparation and mounting. Many impedance tubes have a circular cross-section and can be mounted at various angles. Therefore, it is crucial to investigate the influence of the mounting angle on the SAC and its interaction with diameter imperfections and different thicknesses using different materials. Following the dataset FOAM 01 this work documents the creation of a new dataset (called FOAM 02) containing SAC measurements from the ISO 10534-2 two-microphone method. The following factors are considered: two different materials, four thicknesses, three diameters, and four rotation angles. For each combination of material, thickness, and diameter, three specimens are produced, resulting in 72 specimens. Each specimen is measured three times at each rotation angle, yielding 864 SAC measurements. The dataset contains the SAC measurements and one-hot encoded label vectors, and is publicly available. A cutting device is proposed to saw cylindrical specimens accurately on a band saw with variable thickness and diameter. The workshop drawings of the cutting device are available as supplementary material.