1981 年 37 巻 10 号 p. 484-493
In this paper, a new evaluation method of sound transmission loss of general N-fold walls is proposed by use of the improved statistical energy analysis (S. E. A. ) method as reported in our previous paper. In that paper, the sound transmission loss of a general double-wall was clearly explained in the low frequency region by taking additionally the proper non-resonant power flows into consideration to the primary S. E. A. method as developed by Crocker and Price. This improved S. E. A. method is exactly appropriate for the evaluation of wall transmission losses in both the low and high frequency regions under an actual situation with finite dimensions of transmission room, reception room and panels. On the other hand, this situation is unable to be properly evaluated utilizing the normal methods, i. e. , by the usual wave equation theory, or the equivalent circuit theory. From the above viewpoint, the effectiveness of our general evaluation method of N-fold wall transmission loss by this improved S. E. A. method has been theoretically and experimentally confirmed for many kinds of N-fold wall structures, such as the ordinary (parallel) triple-wall, the absorbent (parallel) triple-wall, the ordinary (parallel) double-wall and the non-parallel double-wall.