Recently one of my subs have started making what I can only describe as a f*rting noise. Originally I thought it was a hole in the box, but have since filled the holes up with silicon and it still makes the noise. Heres q link to the video. https://drive.google.com/file/d/1R-dQmYs2m3r25P1ieN2MNXKZMEV7KPWz/view?usp=drive sdk}
Could be badly bolted or damaged, test the subs individually to make sure what's going on, ideally you will have to replace both subs or run one, make sure you have a proper box for your subs, bad boxes are the cause of many drivers mechanical failure.