| Title |
Fundamental Study on Transient Decay in Acoustic Field of Architectural Closed Space |
| Abstract |
This study was directed toward 'from Geometric Acoustics to Wave Acoustics', 'Analysis about Relation of Variously Shaped Rooms with Their Acoustical Field', 'Great Accuracy', and 'Analysis about Whole Acoustical Space instead of Partial One'. This study was intended first to optimize the unsteady transient decay of the sound, propagated in the simply shaped room, by use of the finite element method and the Schroeder double pulse method. And the second intention was to observe the uniform converge of the solutions to the solutions to the values measured by the scaled model test. This study was performed on the basis of mathematical analysis, scaled model test and signal processing. The procedure of mathematical simulation was followed as;1 Discretizing the time domain using the center-defferential method.2 Deriving the more general formula, in which the boundary and initial conditions are contained, 3 Formulating and calculating the linear matrices of that formula, which was achieved by the finite element method,4 Calculating the steady characteristics of sound field, that is, reverberation time and sound pressure distribution, by use of Schroeder's double impulse method.We could observe the uniform converge of the calculated solutions of impulse response, reverberation time and sound pressure level distribution to the experimental values measured in the 1/10 scale-modeled reverberation room, in which the impulse signal was radiatedby the electrical pulse apparatus.Finally, the finite element method was shown to be very well suited for this kind of problems and its use for more practical acoustic design. |