its been happening on occasion before but now its constant. its hard to explain but ill try my best... the subs will make like bass even if the head unit is not on, as long as the car is on. so lets say im playing my music soft it will make like rumbling noises constanly. its like bass but not bass coming from the song. and if i turn the music off it still rumbles and now its so loud that ill have my H/u off and it will make so much bass i can hear the trunk rattle. i have a stock H/u in my 2k2 maxima. any ideas on whats wrong with my system?