| 摘要 |
PROBLEM TO BE SOLVED: To prevent turn-round of sound radiated from a speaker on the ceiling to a microphone on the ceiling through floor face reflection. SOLUTION: Two or more microphones and speakers are arranged in a dispersed way on a ceiling, and utterance of a speaking person is collected by a nearby microphone and sounded loud from a speaker installed on the ceiling. Each speaker is so arranged that its directivity is turned to a point of a floor face correspondingly just under the center of a line which connects the speaker and its adjoining speaker. In this way, it can be prevented that the sound radiated from the speaker is entered directly to the microphone arranged on the ceiling through floor face reflection, and utterance of howling can be prevented. The adjustment of directivity of the speaker may be realized by adjusting an angle of fitting of the speaker to the ceiling or its directivity may be controlled by constituting a speaker array. COPYRIGHT: (C)2007,JPO&INPIT
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