残響室法音響出力測定における回転拡散板と移動・配列マイクロホンとの関係

概要

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Rotating diffuser is practically indispensable for sound power determenation of discrete-frequency sound source in a reverberation room. If the rotating diffuser has full effectiveness, even a single fixed microphone may be sufficient to measure the space-averaged mean square pressure, or else the relation between the diffuser rotating speed and the microphone traversing or switching speed shall be considered for effective averaging when the microphone traverse or array is used with the rotating diffuser. In this paper, the variances for squared pressure with frequency, microphone position, diffuser direction and those interrelation, and the correlation with diffuser direction were theoretically and experimentallay discussed on a simple plane diffuser, using the field variation coefficient and the number of independent sound fields by the diffuser rotation. Then the good agreement was obtained between theoretical and experimental results. The diffuser vary the sound field incompletely in a room, but create independent fields at every quarter wave length of displacement of the diffuser edge within the varied fields.
社団法人日本音響学会の論文
1985-09-01