| 摘要 |
PURPOSE: To provide a sound transmission device which can transmit sound to an aimed listener alone. CONSTITUTION: By mutually shifting phases of aural signals to be supplies to individual speakers 36 to form synthesis sound waves whose surface wavefronts 104 are concave on the side of sound collecting region 100 whereas convex on the side of nondirectional speakers 36, the surface wave front 104 gradually become small and the synthesis sound waves converge to the region 100 by adjusting phase differences among respective aural signals. Then, the amplitude of the aural signal to be fed to each speaker 36 is controlled so that the sound pressure of the sound emitted from each speaker 36 is of a hearing level or lower. Since the synthesis sound waves are formed by superposing the sound waves emitted from each speaker 36, the sound pressure of the sound converged to the region 100 is of the hearing level or higher. |
