| 摘要 |
<p>A noise attenuation device comprising an array of quarter wave resonators (10), having varying mouth widths w when in use are disposed adjacent an aperture or ventilation opening (73) having a width H. The resonators (10) are tuned to a resonant frequency, increasing from one face of the attenuation device to another, such that w > H. In a second embodiment, a second array (40) tuned to a different frequency is disposed on the opposite side of the aperture (73), the aperture (73) being kinked so that there is no direct line of sight through the device.</p> |
