edmontondown 发表于 2013-1-2 23:56 1 k' N- y0 c ~/ ^yes, may have something fell down on the other end of the hood vent
% R5 V; \# x+ U( l3 l! R# RAt 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.