Empirical Equations for Sound Propagation in Different Sound Absorbent Materials

There are many different types of sound absorbent materials. Nowadays, some simple models are used to characterize these materials. These models are based on empirical equations obtained from measured data. The models are only valid for the studied materials. In the references there are different empirical models to predict the behaviour of some materials. In this investigation, a study of the behaviour of these simple models has been carried out, and some empirical equations for several sound absorbent materials have been proposed.