edmontondown 发表于 2013-1-2 23:56 3 J* Z& l/ |# j" d" L# ]yes, may have something fell down on the other end of the hood vent
4 B7 t4 X5 J. Y C
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.