Prediction of the bulk acoustic properties of fibrous materials at low frequencies

Abstract

In many acoustical modelling applications, it is necessary to be able to predict the bulk acoustic properties of sound absorbing porous media at frequencies below the range of the usual measurement methods for these properties. A semi-empirical prediction method for fibrous media is described here, which not only yields physically reasonable predictions for the bulk properties at arbitrarily low frequencies, but also is in good agreement with measured data at higher frequencies. In this it represents an improvement over previously published low frequency models.