Abstract With short duration impulsive signals used to provide the excitation the vibration level difference across a T-junction of Perspex plates has been measured both as a function of frequency and angle of incidence. Problems associated with high velocity waves and relatively short path differences have been reduced or eliminated by suitable choice of material and geometry, and by use of spatial as well as temporal averaging. Problems associated with the dispersive nature of bending waves have been reduced by use of low pass filtering. Results are presented for point source excitation and comparison is made with plane wave excitation theory. In addition, plane wave excitation has been simulated by means of line averages of the plate response to a point source and these results are also presented and compared with the theoretical ones.