Abstract
A reverberation time is very important for evaluating the reverberation characteristics of a room and the sound power of an acoustic source. The definition of reverberation time is given originally for an acoustically isolated single room. On the other hand, in an acoustically coupled room, respective reverberation times of individual rooms are fairly different from independently measured reverberation times without mutual power flow interactions through apertures or acoustic insulation walls. In this paper, first, a general type characteristic expression of acoustically coupled rooms is established as a power flow system consisting of several subsystems, in close connection with a Statistical Energy Analysis method, corresponding to a kind of system equation in a state estimation theory. On the basis of a solution of this system equation, new type six different methods are proposed on trial by introducing various type evaluation criteria so as to evaluate the reverberation time of the acoustically coupled room system, especially from various type system-theoretical viewpoints. Finally, the effectiveness of the proposed theory is experimentally confirmed by applying it to the actual coupled acoustic rooms and the above six evaluation methods are compared with each other.
