Sound transmission through simple and double infinite covers

Abstract

The sound transmission of simple and double infinite walls or covers is studied in this paper. The proposing model is used to describe the acoustic behaviour of these structures. The complexity of the dynamical system requires the use of an electrical analogy that allows using Kirchhoff’s laws and the impedance matrix of a quadrupole. The characteristic impedance and the propagation constant of each element are required as input parameters. This model was computed to calculate transmission loss for plane incident sound waves. Then, the results were both compared with the simplified London-Beranek model, which can only be applied to double walls with the same mass, and with experimental data. The simulations also showed the influence of the mass of each wall and the thickness of the air cavity on sound transmission.