抄録
The influence of shape and size of a dummyhead upon the sound reaching the ear is discussed. The Thévenin acoustic impedance and Thévenin pressure, which have been adopted as acoustical parameters for evaluating the effect of individually different shapes and sizes of the human head (K. Fukudome, Proc. 10th Int. Congr. Acoust.(Sydney) 1980), are numerically examined by using two types of model heads. The shape and size of the model heads, respectively a sphere and an oblate spheroid, were changed according to head circumference and the cephalic index of the somatometry of the head. As a result, it was found that the Thévenin acoustic impedance is hardly influenced by the shape and size of the model head. The influence of head shape and size upon the maximum of absolute value of log magnitude and phase of Thévenin pressure was illustrated in terms of an equal magnitude contour and an equal phase contour. A final discussion deals with regards for an average head in shape and size as a head which is acoustically standard.
