| 摘要 |
PROBLEM TO BE SOLVED: To overcome such a problem that since it is difficult to emit an audible sound having a band directively, a voice announce can not be radiated directively to a specific user in a voice announce system, for example, and a voice announce for giving caution quickly and surely to a user in a dangerous situation can not be provided. SOLUTION: The super-directive speaker comprises a sound source 16 generating an audible sound, i.e., and announce signal, a sound radiation controller 18 for controlling the sound emission characteristics of the announce signal, and a speaker 9 emitting the announce signal having the sound emission characteristics controlled by the sound emission controller 18 as a voice announce.
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