The feasibility of building an impedance tube to measure sound absorption coefficients of materials

Abstract

This presentation focuses on the design and build of an impedance tube to measure sound absorption coefficients of materials. A practical approach was taken to develop an impedance tube from readily available ‘off the shelf’ materials, with the ultimate goal of determining feasibility and accuracy of such a build. The design theory from multiple sources will be discussed, as well as a detailed breakdown of the dimensions and materials used for the apparatus. Measurement methodologies, testing set-up and data processing techniques are also presented to contextualize the results. Finally, comparisons of the tube results are made to existing known sound absorption coefficient data of materials to ultimately assess the accuracy of the low-cost impedance tube and any deficiencies. Methods to improve the design of the tube are also explored, as well as future design improvements.