edmontondown 发表于 2013-1-2 23:56 & ~8 w+ \( ^6 b7 h0 oyes, may have something fell down on the other end of the hood vent
, W2 B0 E) A8 I" tAt 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.