抄録
This paper describes an improved model of the sound sources which were reported in the previous paper [K. Matsuzawa, Acustica 37, 241-248 (1977)]. Each sound source consists of a vibrator for use at 20kHz, a metallic horn, and a thin metallic diaphragm in flexural vibration. The efficiency and some of the near-field properties for this improved model were reported in the previous short note [Y. Sasaki et al., J. Acoust. Soc. Jpn.(E) 1, 209-210 (1980)]. In this paper, the far-field properties are described and in addition near-field properties. The intense sound field near the diaphragm is confined in a region of some centimeters. The radiation pattern at 1m distance has a single peak or double peaks about a peculiar direction. Numerical studies have been made using the theoretical formulas given in the previous paper. Though the improvement in strength caused a little discrepancy between the real construction and the theoretical counterpart, the experimental results are in good agreement with the calculated ones with respect to both the near-field and the far-field properties.
