edmontondown 发表于 2013-1-2 23:56 1 s+ t7 V; X$ m j% d, t: Y a
yes, may have something fell down on the other end of the hood vent
1 p" q# M/ e0 b; F: @At 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.