edmontondown 发表于 2013-1-2 23:56 ! f% }% l2 Q* Z% Q( T
yes, may have something fell down on the other end of the hood vent
/ @* L1 H. n! [ h/ xAt 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.