edmontondown 发表于 2013-1-2 23:56 / O- d( W: o5 `: Byes, may have something fell down on the other end of the hood vent
& f/ H) H: |0 X5 P2 ?% ?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.