edmontondown 发表于 2013-1-2 23:56 6 ~! @9 F# N; `; g
yes, may have something fell down on the other end of the hood vent
* k$ |' C4 Y+ N( n# P$ r7 X9 r. v5 ~At the other end(outside) of the vent duct, there is usually a metal cover for the opening, it can swing up and down and if it is a windy day, it will be blown swinging, thus making a kind of banging noise.