In the majority of engineering applications, porous sound absorbing media may be treated as equivalent fluids, with vibration of the solid skeleton being neglected. Most measurement techniques for the bulk acoustic properties of such media (e.g., complex characteristic impedance and propagation constant) involve tests on large samples of material, rather complex series of tests on smaller single samples, or surface impedance tests on two small samples of differing thicknesses. Recently, however, a least-squares method [C. Braccesi and A. Bracciali, Appl. Acoust. 54, 59–70 (1998)] was employed to find values of the structure factor and flow resistivity, in a two-parameter model, from a single surface impedance curve. Though the technique proved successful, the two-parameter model is less accurate over a wide frequency range that the well-known empirical curve fitting method of Delany and Bazley. In the present paper, a least-squares method is described for determining the eight empirical parameters in the Delany and Bazley method from a single surface impedance curve. Examples of its application are given, and it is demonstrated that it gives a better fit to measured data than the two-parameter model.