Direction Measurement of a Sound Source in 2D Space Utilizing Differences of Sound Levels Given by Two Sets of Condenser Microphones.

This paper proposes the measurement principle of a sound source direction in the two-dimensional space. Such kind of differences like the transferring time, phase shift, and level of the sound wave are treated for the measurement in general. Our approach is to use the differences of sound levels by taking the advantage of the condenser microphone's simple sensitivity characteristics in directivity so that the direction is obtained by the simple signal processing. Basically the minimum number of the microphone set is three for the triangular arrangement. However, the set composed of four microphones for the orthogonal arrangement is treated for high accuracy. Formulation of the relations among the differences of the sound levels is shown. Also, the calculation procedure for determining the direction is extracted and experimental results are shown to verify the validity of the measurement.