The classical edge diffraction problem has an exact solution for infinite and truncated wedges. There are no explicit solutions for finite wedges but approximate formulations have been presented, many of which are based on the Kirchhoff diffraction approximation. These methods fail at low frequencies and for certain geometries. A method suggested by Medwin et al. [J. Acoust. Soc. Am. 72, 1005--1013 (1982)] for finite wedges, based on the exact Biot--Tolstoy solution, has proven successful when applied to noise barrierlike geometries. They tentatively propose a method for handling multiple diffraction. In the present paper their method is tested for the application of a boxed loudspeaker, a case where multiple diffraction is clearly evident. Comparisons are made with boundary element calculations. Modifications to Medwin's method are discussed and other methods, for example, as suggested by Vanderkooy [J. Aud. Eng. Soc. 39, 923--933 (1991)], are discussed as well. Time-domain formulations, such as those discussed here, give insight to the polarity, time delay, and time distribution of the higher-order diffraction components.