| 摘要 |
<p>PROBLEM TO BE SOLVED: To lower the noise level of a specified frequency band even if the pressure of a sound source side fluctuates. SOLUTION: Plural pistons 7, 8 respectively moving in specified ranges in response to the pressure change of a sound source 1 are provided in an accumulator 6 connected to the sound source 1, the pistons 7, 8 partition the inside of the accumulator 6 into plural gas layer rooms 11, 12 in which gases having different filling pressures are filled, and above mentioned moving walls move in response to the pressure change of the sound source 1 so that the gas layer lengths of the respective gas layer rooms 11, 12 change. When the pressure of a sound source side increases, the liquid mass and the gas layer length of the whole accumulator increase automatically and a sound is attenuated by a resonance system composed of the increased liquid mass and gas layer length. Thereby, the noise level of a specified frequency band can be automatically lowered even if the pressure of the sound source changes.</p> |
