edmontondown 发表于 2013-1-2 23:56 7 S: j" e. ~, M- K2 X3 ?% L8 v5 I
yes, may have something fell down on the other end of the hood vent
& K. X' X% ?) Z/ n; R. L* j J9 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.