edmontondown 发表于 2013-1-2 23:56 5 ?! s) |) U, ^0 {8 y& w
yes, may have something fell down on the other end of the hood vent
" F# [" G5 M- j! Y* P. C& 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.