| 摘要 |
An acoustically resistive protective cover assembly for an opening in a casing is provided, the casing separates an enclosed space from the ambient space and has an exposed face oriented toward the ambient space and an internal face oriented toward the internal space. The cover assembly comprises an acoustically resistive porous material disposed upon the exposed face of the case and an acoustically resistive water repellant material disposed upon the internal face of the case. |
