my black lab has two types of farts.....the loud one that makes him jump up and look back trying to figure out what the hell that was, those USUALLY won't have an odor...then there is the very quiet whooooosh one that you hopefully hear so you are prepared for the stench, cause if you don't hear it, it is like getting slapped in the face. These for some reason don't wake him up the big lug, but will wake dh and from a sound sleep!