| 摘要 |
<p>PURPOSE:To obtain a high muffler effect while reducing the number of necessary equipment of a second sound source in an active muffler device for duct. CONSTITUTION:In the constitution providing the second sound source 3 generating a second sound with a phase opposite to a first sound propagating through the inside of a duct 1 facing a duct end opening, and providing emission parts 4a, 4b emitting the second sound generated from the second sound source 3 to the inside of the duct 1 on the duct walls 1a, 1b, plural emission parts 4a, 4b are provided, and these emission parts 4a, 4b are arranged dispersedly in the circumferential direction of the duct 1, and second sound distribution paths 5a, 5b distributing the second sound generated from the second sound source 3 for plural emission parts 4a, 4b are provided. Further, preferably, the emission parts 4a, 4b are arranged on equal positions in the duct center direction of the duct 1, and the path lengths of the second sound distribution paths 5a, 5b for respective emission parts 4a, 4b are made equal.</p> |
