edmontondown 发表于 2013-1-2 23:56 5 k* N8 t' l' S+ Vyes, may have something fell down on the other end of the hood vent
! h, i+ Q( F1 r- w m+ J7 CAt 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.