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Poroelastic materials are commonly used in passive noise control due to their low cost and relative efficient acoustic absorption characteristics in the middle to high frequency range. They are constituted by a rigid and a fluid phase responsible for the dissipation mechanisms attenuating the propagation of acoustic waves inside the material. The understanding of these phenomena and their translation into parameters existing in the mathematical formulations for poroelastic materials are of paramount importance in the design of optimized structures for choosing the proper materials for each application. This work presents studies on the validation of a melamine foam characteristics using the equivalent fluid model from Johnson-Champoux-Allard (JCA) and a rigid structure.

Simple and complex sound sources can be constructed using loudspeakers assembled on the surfaces of platonic solids such as the cube and the dodecahedron, whose implicit mathematical properties enable their application in acoustic radiation studies. By using special phase combinations of the electric signals applied to each loudspeaker, complex sound fields can be produced with their distinct spatial patterns. In many applications (such as aeroacoustics of cars and airplanes) monopoles, dipoles and quadrupoles are sufficient in the investigation of acoustic phenomena. Their experimental validation is usually performed using a circular microphone array to measure the sound pressure field around the test object. This approach can be very complicated and poses many challenges in terms of test setup, execution and post-processing. Therefore, there is a need for new experimental methods to characterize acoustic sources.