Air-flow resistivity is a very important parameter for characterizing porous sound absorbing materials. A number of theoretical models are dependent on values of air-flow resistivity. Air-flow resistivity has also been used in the selection of materials for noise insulation and room acoustic applications. However, direct measure of air-flow resistivity is not simple. To overcome this problem, several indirect alternative methods have been proposed, such as the one proposed by Ingard & Dear in a standing wave tube. In this work, an electroacoustic procedure is proposed to determine this parameter from the method devised by Ingard & Dear. It is shown that, under certain conditions, the air-flow resistivity can be obtained from direct measurements of electric impedance.