edmontondown 发表于 2013-1-2 23:56 4 U+ t$ ^0 V( _: P* N0 ?- N# {: tyes, may have something fell down on the other end of the hood vent
+ k. F M c1 P9 O* ^& X, LAt 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.