PREDICTION OF THE BULK ACOUSTIC PROPERTIES OF FIBROUS MATERIALS AT LOW-FREQUENCIES

In many acoustical modelling applications, it is necessary to be able to predict the bulk acoustic properties of sound absorbing porous medi a 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 predic tions for the bulk properties at arbitrarily low frequencies, but also is in good agreement with measured data at higher frequencies. In thi s it represents an improvement over previously published low frequency models. (C) 1998 Elsevier Science Ltd. All rights reserved.