The nature of breakin is a continuum. Designers have had the task of soft selling breakin to make it easier on the end user. Saying 40hrs, 400hrs or 400days is really nothing more than a selling point so that the designer (and listener) can have an excuse for why their system sounds the way it does. Truth is, anything that passes a current or is subject to the fundamental forces on this planet continues to mature forever.
When you think about it, it's really cool that our audio systems (including room and environment) are so flexible. I like using the term "mechanical conduit" to describe the parts of everything in our audio chains. As much as HEA has tried to paint the picture of isolation, it really comes down to our systems are moving all the time and that means is in constant change in performance. It's nothing to freak out about in fact, once you get it, the hobby takes an interesting turn for you. It's very much like having a guitar and playing a guitar.
Michael
