edmontondown 发表于 2013-1-2 23:56 9 X6 X: E+ _) dyes, may have something fell down on the other end of the hood vent
5 z8 H. x+ Z- g+ Q* G# E" WAt 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.