Acoustical treatments with porous materials are widely used to reduce reverberation
properties of closed spaces and to increase the transmission loss properties of multilayered
panels. The optimization in a broad frequency range of sound absorbing layers
encapsulated in multilayered panels requires exact knowledge of the acoustical behavior of
porous materials and cannot be made with usual global acoustical parameters valid only at
the higher frequencies. In this work a simple methodology to estimate the main acoustical …