Is subwoofer failure the norm?
I've only owned one sub (a 28 year old Mirage bought brand new), and I've nursed it for the last 5 years with judicious use of contact cleaner. I thought last November was the death knell, but somehow it stopped squealing after my 9th or 10th dose. Even the foam surround is intact, and sounds like the day I bought it.
I've seen various forum posters mention their sub failures, but I've been under the impression that it's because they use switching power supplies or were abused.