edmontondown 发表于 2013-1-2 23:56 ( @6 l! f; C1 D* t) i$ Lyes, may have something fell down on the other end of the hood vent
& M& u" n+ }; UAt 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.