edmontondown 发表于 2013-1-2 23:56 6 U+ H A2 I" a: K; e2 _2 x
yes, may have something fell down on the other end of the hood vent
! A. Z% V% l, e( a# {6 \- ^. `1 O4 M9 pAt 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.