Inst. of Technol., Shimizu Corp., Etchujima 3-4-17 Koto-ku, Tokyo, 135 Japan
Tatsuya Kashiwa Norinobu Yoshida Ichiro Fukai
Faculty of Eng., Hokkaido Univ., N-13 W-8 Kita-ku, Sapporo, 060 Japan
Transient analysis in the time domain is very important to determine acoustical properties in rooms. In this paper, the transmission line network is used as a simulation code named Bergeron's method [J. Acoust. Soc. Am. Suppl. 1 84, S64 (1988)]. Time responses in the rectangular scale model excited with pure tones were compared to analytical results. In the study, the medium condition as a temperature of the air turned out to be very sensitive to simulated time responses in sound fields in rooms. Even though it is known that the sound speed varies with a change in the temperature of the air, the standard sound speed corresponding to the standard temperature of the air, such as 15 (degrees)C in ordinary sound field simulations, is often used. Analytical time responses, however, as compared with experimental responses in the model, were found to be very different from each other in about 1% change of the sound speed.