Study of the active sound field control in building acoustics

本研究计划探讨主动式噪声控制技术的原理及其在建筑声学中的应用，并取得以下成果。(1)主动吸声：作为主动控制在吸声中的一个基本应用，本文研究了利用一个扬声器、两个参考传声器和“滤波-X”LMS算法产生以吸收边界为终端的一维声场的方法。(2)主动隔音：为了研究主动控制技术提高建筑墙体隔声性能的有效性，进行了自适应前馈控制的基础实验。结果，已经发现，可以恢复双层壁的隔音缺陷，并且可以减少来自开口的声音传输。(3)管道系统中的主动降噪：作为暖通空调管道系统中降噪的一种方法， ...更多信息 应用于多室管道。将试验结果与有限元计算结果进行了比较，两者吻合较好。(4)声强主动控制：对声强作为噪声主动控制的参考量进行了理论和实验研究。(5)主动控制在通风系统中的应用：通过缩尺模型试验，研究了主动噪声控制技术在某电站通风系统中的应用。(6)主动模式控制：为了降低封闭空间中低维模态引起的声压，通过边界元法计算和缩尺模型实验研究了主动控制的应用。(7)静区的产生：为了在嘈杂的房间中产生局部静区，通过实验检验了主动控制的有效性。(8)管道系统中的主动振动控制：针对结构振动问题，使用含水管道系统进行了实验。结果表明，主动控制技术可以有效地抑制管道系统的振动传播和噪声辐射。少

This research project has been planned to investigate the principle of active noise control technology and its applicabilities in building acoustics and the following results have been obtained.(1) Active sound absorption : As a basic application of active control to sound absorption, the way of producing an 1-dimensional sound field terminated with an absorptive boundary by using a loudspeaker, two reference microphones and the "Filtered-X" LMS algorithm has been studied.(2) Active sound insulation : To investigate the effectiveness of the active control technology for increasing the sound insulation of building walls, basic experiments using the adaptive feedforward control have been conducted. As a result, it has been found that sound insulation deficiencies of double walls can be recovered and the sound transmission from the openings can be reduced.(3) Active noise reduction in duct systems : As a method of reducing noises in HVAC duct systems, the adaptive feedforward control was … More applied to a multi-chamber duct. The effect obtained by the experiment was compared with the FEM calculation results, and a fairly good accordance was found between them.(4) Active control using sound intensity : The method using sound intensity as the reference quantity in active noise control was investigated theoretically and experimentally.(5) Application of active control to air-ventilation system : The application of the active noise control technology to air-ventilation system in a electric power station was examined by a scale model experiment.(6) Active mode control : To reduce the sound pressure caused by low dimensional modes in closed enclosures, the application of active control was examined by BEM calculation and scale model experiment.(7) Production of quiet zone : To produce a localized quiet zone in noisy rooms, the effectiveness of the active control was examined experimentally.(8) Active vibration control in pipe system : Regarding the structural vibration problems, an experiment was conducted using a pipe system containing water. As a result, it has been found that the vibration propagation in pipe system and resulting noise radiation can be reduced by the active control technology. Less