Eisner has concocted a clever geometrical arrangement that appears to contradict the principle of acoustic reciprocity. In essence his example consists of a truncated opaque ellipsoidal reflector with the source and receiver situated at the foci as shown in Figure 1. In the limit of geometrical optics it is evident that only half the energy emitted by a source at 2 will contribute to the reflected arrival at 1 while a substantially larger fraction of the energy emitted by a source at 1 will appear at 2. Naively it seems as if the geometrical amplitude of the reflected arrival at 2 should exceed that at 1, in apparent violation of the reciprocity theorem.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.