Abstract
The attenuation characteristic of the N-fold walls is studied as a function of frequency by taking into consideration the effects of the resistive factor which was firstly introduced by A. London, the coincidence phenomenon and the internal dissipation factor in air space with the aid of the equivalent circuit method(especially introducing an equivalent distributed constant circuit model for the system under consideration)which seems more flexibly applicable than the wave equation method by A. London and the multiple reflection method by K. A. Mulholland. The validity of the present theory is confirmed experimentally using the transmission losses(measured at Kanagawa Prefectural Environmental Center and Hiroshima University)
