A 3D modeling method of layered acoustic material structures with finite dimensions

Modeling of layered acoustic structures to predict the sound absorption characteristics of complex materials is a widely used method in room acoustic practice. Commonly used modeling techniques-such as the transfer matrix method-typically assume locally reacting surfaces of infinite lateral dimensions and provide one-dimensional calculations only, offering limited accuracy, especially for resonant absorbers with finite dimensions. We present the direct, analytical modeling of sound propagation in extendedly reacting layered materials of finite dimensions allowing the estimation of the surface impedance or admittance distribution of layered structures, from which sound absorption properties can be calculated. The theoretical results are validated by measurements, performed on a small-sized resonant panel absorber. We present the implementation of the method in the soundy.ai application.