edmontondown 发表于 2013-1-2 23:56 ' a( O2 U2 q8 W$ T; L) \
yes, may have something fell down on the other end of the hood vent
. r0 E3 Z9 p2 S( p& F6 dAt 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.