Subwoofer noise. Sub suddenly makes loud buzzing sound and air blows through hole in bottom of sub

Question

Sub suddenly makes loud buzzing sound and air blows through hole in bottom of sub when stereo/home theater system is off. Sub works fine when stereo/home theater system is on.I have tried turning sub off and back on, **ise comes back eventually. I have tried uplugging power supply at sub and receiver to reset, ** luck!