My home speakers consisted of Eminence Kappa 12's, a P. Audio 1'' compression driver on a B&C ME45 horn, JBL 2405's and a 15'' Fostex sub.
One morning one of the Kappa's had simply thrown in the towel. I have never used these speakers at any power level - a few watts at its most, so that sudden failure came as some surprise.
A quick investigation revealed that the voice coil had lost all contact with the world as we know it, no DC resistance whatsoever (open).
After discovering that this happened 1 year and 1 week (but of course!) after purchase I phoned the distributor and he said send the driver back.

So I did and phoned the guy a couple of days later, eager to hear what had happened. - Oh, well he said, this is interesting, the entire connection to the voice coil has burned away.
- Has it really burned away, I replied? I have a hard time believing that.
- Yes, uh well no it has not burned away. It is more like it is rotten.
- Rotten????
- Uh well, more like it has disintegrated. Vaporized. It can happen.
- Now look, I said. I am an electrical engineer working daily with equipment a tad bit more complicated than a loudspeaker driver. Things just don't "disintegrate". And if they do, that sure should not be considered "normal". I have operated these drivers at a fraction of a percent of their rated power and been far from exceeding Xmax. Surely if I had used them at 50% rated power for a year or so they could break and that could be considered more or less "normal". But not by more or less merely looking at them.
- OK, I will speak to the Eminence rep and see what I can do, the guy answered. But since the one year warranty period has expired, don't expect anything.

A couple of weeks later I received a new driver, having just to pay for the shipment (about $40). Fair enough.
But by that time I had already replaced the Eminence's with second-hand Fane Studio 12B's. Great drivers and I am not switching back. Distortion seems to be halfway between Eminence and JBL's. But then, these drivers retail for about the double as the Eminence's.

So bottom line, Eminence customer support seems really good. How about quality control then? I don't know. Most probably simple faults like this are rare. But it should not even happen in the first place IMO.

Cheers
/Magnus