| 摘要 |
PROBLEM TO BE SOLVED: To provide a noise eraser for a duct the mounting work of which can be done easily, and also which can be inspected and repaired easily, and can reduce the occurrence of wind cutting sound. SOLUTION: A noise eraser 1 for a duct comprises a duct unit 2 which constitutes a part of a duct, a microphone unit 3 which has a directional microphone 3a and a speaker unit 4 which has a built-in speaker 4a. The mounting work becomes simple by unitizing the duct unit 2, the microphone unit 3, and the speaker unit 4, and also if a user removes the units 3 and 4 in use, he can inspect and repair it easily. Setting the directional microphone 3a to the supporting material 6g attached to a cover 6 and adjusting the angle of the supporting member toward the noise source and fixing the cover body 5 to the duct unit 2 will enable the occurrence of the wind cutting sound to be lessened because the directional microphone 3a is arranged in the vicinity of the inwall of the duct unit 2. |
