| 摘要 |
PROBLEM TO BE SOLVED: To provide a noise reduction device capable of reducing noise without a sound insulation wall. SOLUTION: An instrument 10 which generates a low-frequency sound and a noise is not surrounded by a sound insulation wall, but surrounded by control poles 20 in which a plurality of control speakers 21 are linearly disposed at constant intervals in a columnar support. A sound (dashed lines) of a frequency of the phase opposite to the phase of the low-frequency sound generated from the instrument 10 is generated from each control speaker 21 to the other side of the instrument 10. The sound mutually interferes with the low-frequency sound (solid lines) generated from the instrument 10 outside the control poles 20, thereby giving the effect of reducing noise. COPYRIGHT: (C)2007,JPO&INPIT
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