edmontondown 发表于 2013-1-2 23:56 5 R# Y# M% j# [1 ryes, may have something fell down on the other end of the hood vent
9 S5 }! {2 N0 F5 }8 sAt 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.