The aim of this study is to numerically evaluate a tunneling effect in the laboratory measurement of sound transmission loss. The tunneling effect arises from the depth of an aperture in the common wall between the source and receiving rooms. Variations of the sound transmission loss with the parameters of panel location, tunnel depth, and panel size are investigated. The difference in sound transmission loss is quite evident below the coincidence frequency and it greatly depends on the panel location in the tunnel. In comparison with the transmission loss of a finite plate in an infinite rigid baffle (with no tunnel) the maximum difference occurs in the laboratory measurement when the panel is placed at the center of the tunnel, while a better estimation of true transmission loss is obtained when the panel is located at either end. The results provide an added guideline for the standard laboratory test method for sound transmission loss.

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Stress wave propagation in a coated elastic half-space due to water drop impact is studied by using the Cagniard-de Hoop method. The stresses have singularity at the Rayleigh wavefront whose location and singular behavior are determined from the pressure model and independent of the coating thickness, while reflected waves cause minor changes in amplitudes.