edmontondown 发表于 2013-1-2 23:56 + n6 [7 Q1 [7 C J$ x o
yes, may have something fell down on the other end of the hood vent
8 S. r7 J& B& k$ y" gAt 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.