Hi I am new here and am in need of some help. My subwoofer jsut recently started making a humming noise(60hz) and disconnect it from the home theater and it continues to him with power. The unit when connected receives bass and plays but with the humming. I’ve taken it apart and checked the capacitors and they seem good but haven’t tested them. Also I have moved it to another room to see if it was ground interference but still has a the hum. It becomes louder when polarity is flipped 180. Any help on diagnosis would be much appreciated.