| 摘要 |
PROBLEM TO BE SOLVED: To eliminate both a noise source primary sound generated within a rotating machine and an environmental primary sound generated within an enclosure. SOLUTION: A microphone 3 and a speaker 4 are provided opposite to each other within an enclosure 1 in such a manner to be capable of oscillating, and a microphone 5 and a speaker 6 are also provided opposite to each other within a rotating machine 2 set in the enclosure 1 in such a manner to be capable of oscillating. The environmental primary sound collected by the microphone 3 and the noise source primary sound collected by the microphone 5 are read into a computer 7 to analyze the waveforms of the noise source primary sound and the environmental primary sound, waveforms having the same amplitudes as these sounds and the reverse phases thereto are formed to generate the environmental secondary sound for interfering with the environmental primary sound through the speaker 4 and the noise source secondary sound for interfering with the noise primary sound through the speaker 6, respectively. Further, each of the microphones and speakers are moved so as to regularly minimize the noise level.
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