An acoustic method is proposed for measuring the low frequencies parameters of porous materials having a rigid frame. The Biot equivalent fluid model is considered, in which the viscous losses are described by the the static viscous permeability and an additional viscous parameter. The inertial interactions between fluid and structure are taken into account by the inertial factor. The thermal couplings are modeled using the thermal permeability and the thermal tortuosity. The proposed method is based on a solution of the direct and inverse problems for the propagation of transient audible frequency waves in a homogeneous isotropic slab of porous material having a rigid frame. The physical parameters are determined fromthe solution of the inverse problem using experimental reflected and transmitted waves by porous samples, in a wave guide (pipe). The minimization of the objective function, defined as the difference between experiment and theory, is done in the time domain. Tests are performed using industrial plastic foams. Experimental and theoretical data are in good agreement. Furthermore, the prospects are discussed.