| 摘要 |
PROBLEM TO BE SOLVED: To provide a loudspeaker system in which a target speech can not be heard clearly at a spot other than a specific target spot. SOLUTION: Speakers 20-1 to 20-n are disposed in a two-dimensional or three-dimensional manner towards a loudspeaker area. A target speech such as a calling announcement is emitted while matching emission timings of the speakers so as to match the timings at a target spot that is a place where a person desired to be called is located. Thus, at the target spot, the timings are matched and a clear speech at a high sound pressure level can be heard. At other places, timings of speeches heard from the speakers are deviated, clearness is reduced and contents can not be heard. Furthermore, respectively different random signals are emitted from the speakers, an S/N is reduced at a spot other than the target spot. COPYRIGHT: (C)2009,JPO&INPIT
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