edmontondown 发表于 2013-1-2 23:56 ( x2 E( `4 [9 {* E7 f$ b3 e$ p+ D2 ryes, may have something fell down on the other end of the hood vent
" |+ R9 U" U: k) z" 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.