Subwoofers are just like any other amplified speaker in that you have a speaker and a power source.

Common failures:

The amp module can fail, which can be manifested as a ground buzzing, a “whump whump whump” noise that sounds like a helicopter landing (scariest at 2am), or just no output what-so-ever.

The speakers can blow, which sounds like a buzzing or rattling.

We service many brands of subwoofer, including: B&W, Velodyne, JBL, Mackie, Klipsch, Mirage and more.