edmontondown 发表于 2013-1-2 23:56 $ _8 L' A6 S2 F1 t
yes, may have something fell down on the other end of the hood vent
% ?0 }* j) G! t9 N+ K) o4 nAt 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.