Just over a week ago my driver’s side HK door woofer started making a grumbling noise, and the next day it would cut in and out completely. Last Saturday I pulled things apart to find the problem, and found this:
Water had come in through the window seal (which is confirmed by my service tech as normal) to the inside of the door, but the speakers are fully exposed and as you can see got dosed with water. The fragile wire going to the actual speaker corroded and was no longer conductive.
After a few days of driving with no music but that of my engine, I drove up to MINI of Peabody and got the speaker replaced under warranty. But I certainly do not want this happening again, so I made another cheap HK fix. A $7.99 pair of foam speaker baffles now protects the speakers from the elements.
I have detailed the process on my HK Door Fixes page. I also took the opportunity to rewrite the entire page and update it with some new information. This is something that may eventually happen to every MINI, so it is worth the quick and cheap fix before it happens to you.