This dataset provides the data for Reference: [1] Alfonso Caiazzo, Florian Kraxberger, Christian Adams, Andreas Wurzinger, Jan Boysen, Giuseppe Petrone, Stefan Schoder, Sergio De Rosa, Manfred Kaltenbacher, and Christian Adams: FOAM 02: A dataset of impedance tube measurements with different materials and diameter variations. Acta Acustica 9 (50), 2025. https://doi.org/10.1051/aacus/2025033 This dataset consists of three .csv files: alphas.csv: absorption coefficients vs. frequencies (comma-separated), 864 rows according to 864 measurements targets.csv: one-hot encoded, i.e., binary, vectors of the parameter combinations), 864 rows according to 864 measurements. The Read_Me.pdf gives further information on the one-hot encoded vectors. diameter.csv: calliper diametric measurement in millimetres [mm]. This file contains 864 rows according to 864 measurements and 6 columns that, in order, represent: top diameter at 0°, top diameter at 90°, bottom diameter at 0°, bottom diameter at 90°, mean diameter, and standard deviation. The frequencies range from 150 Hz to 1600 Hz with resolution of 2 Hz. Note that these limits are not strictly equal to the frequency limits of the impedance tube, see ISO 10534-2. The data and code are licensed under Apache License, Version 2.0 https://opensource.org/licenses/Apache-2.0 Any reuse of the data must properly cite the dataset and its authors. Contact:Univ.-Prof. Dr. Christian AdamsGraz University of TechnologyInffeldgasse 16c8010 Graz, Austriachristian.adams@tugraz.at