| 摘要 |
PROBLEM TO BE SOLVED: To provide an active silencer for a duct, capable of being installed in an arbitrary position in a duct. SOLUTION: This active silencer is equipped with at least one first sound wave detecting means 2, provided along the propagating direction of sound wave for detecting sound wave in a duct 1, a first traveling wave component detecting means 51 for detecting traveling wave components of the sound wave based on a result of the detection, at least one sound wave generating means 3 provided on the downstream side of the first sound wave detecting means for reducing the traveling wave components detected by the first traveling wave component detecting means 51, at least one second sound wave detecting means 4 provided on the downstream side of the sound wave generating means for detecting sound wave in the duct 1, a second traveling wave component detecting means 52 for detecting traveling wave components of the sound wave based on a result of this detection, and a control means 6 for controlling the sound wave generating means so as to reduce the traveling wave components detected by the first and the second traveling wave component detecting means 52. |
