Reflection of spherical sound wave from a rigid sphere

A calculation method for the amplitude of reflected sound waves at a rigid sphere is descrived. This method is expressed in the terms of the "directional sound reflectivity of the spherical body", which is the ratio of the sound pressure of the reflected wave from a spherical body at the position of the receiving point to the particular pressure calculated by the theory of geometrical optics. Some experiments were performed so as to verify the validity of these theories. In these experiments, the results qualitatively agree with the theories.