RE. The reason titanium and aluminum are chosen as driver materials is that they're light and rigid. Why would you want them to soften up? It would muddy the sound. If you're referring the the other parts of the speaker breaking-in -- the surround and the spider -- then those are the same regardless of the actual cone material.
I guess I really wasn't sure of what 'break-in' is supposed to do. I apparently misspoke by using the 'softening up' commment. Here's an excerpt from the review that sparked my comment:
http://www.onhometheater.com/product/20020801.htm
(okay, explain how to paste this as a link. Rookie move)
...following, as it did, on the heels of the Thiel PowerPoints, which cost $1300 each, and the superb Polk LSi15-based system, which costs about twice as much as the Axioms.
And, I must confess, the transition was not a painless one. The Axioms definitely have a break-in period during which the tweeter seems quite rough and the woofers seem decidedly lightweight. But over time that began to change, and it wasn't long before I began to notice how much I was enjoying films and music through the system. ...
