Well, I always thought that people were crazy when they would talk about headphone break in. I have a pair of K701's powered by a Woo Audio 6 amp. I was very pleased with the sound when I first got the setup, but now I'm totally thrilled! These things have transformed almost within a weeks time. All of a sudden the low end has become much tighter and deeper. The highs. and mids have also improved in smoothness, and warmth. I don't know exactly how many hours I have on them, but they are now the best phones I have ever heard. I'm finding myself listening to these more than my B/W 801's. It's true, things do get better with time.