| 摘要 |
The panels have a front wall (2) placed towards the source of noise. This wall has a predetermined number of perforations. The back wall (3) is not perforated and between the two there is a layer of absorbent material (4). There is a gap (5) between the back (4A) of the absorbent layer and the inner surface (3A) of the back wall. In this gap (5) there is a perforated partition (6) which is situated at a predetermined distance (D) from the back wall, so that it is closer to the insulating material (4) than the back wall, to ensure that there is an open area. The degree of perforation of the internal partition (6) and its distance (D) from the back wall are chosen to maximise its ability to filter out low frequency noise. |
