edmontondown 发表于 2013-1-2 23:56 7 A3 j* j* L4 B6 I$ W& T- A
yes, may have something fell down on the other end of the hood vent
& @1 S7 c# u9 h2 m' ~( @4 j! 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.