| 摘要 |
PROBLEM TO BE SOLVED: To provide a noise reducing apparatus which can reduce noise diffused from a noise source in a wide range even if noise has directivity. SOLUTION: When noise from the noise source has directivity, the directivity of the noise from the noise source is calculated based on sound wave information items of a sensor microphone and a speaker proximity microphone 38 by a signal processing section, and a directivity correction coefficient is calculated for each speaker 12 according to the calculated directivity. Then the directivity correction coefficient is set for each delay circuit, and the amplitude of a reducing signal is corrected in a manner of correcting the intensity of a control sound according to the directivity correction coefficient. Thus the directivity of a control sound emitted from each speaker 12 becomes equal to the directivity of the noise, and therefore even if the noise from the noise source has the directivity, the noise from the noise source can be canceled in a wide range inclusive of a control point. COPYRIGHT: (C)2008,JPO&INPIT
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