Abstract
Measurements of the vibration acceleration at one point of the plate and that of the sound pressure near the plate surface were made in succession with the preceding report of the same title. The stiffness of rubber hammer were measured and the impulsive force figures were observed by using piezo-electric materials and a synchroscope. Attention was given to the coincidence frequency which makes the wave length of the sound in air equal to that of the flexural vibration in the plate, as well as to the force figure, and following results were obtained: 1) The correspondence between vibration acceleration and sound pressure is fairly complex depending upon the properties of materials and its thickness. As to the radiation of sound from a plate, the coincidence effect could be observed, but not so remarkable as expected from the theory. 2) By reducing stiffness of the hammer, the components of high frequency of sound pressure and vibration acceleration tends to disappear, but on the contrary, not so much difference can be observed in a low frequency region. The force figure decides the frequency response and it varies according to hammer stiffness, weight and velocity.
