My own real-world experience echoes The Professor's post very closely. I bought a brand new pair of ProAc Response 1 SCs back in 2004 (I'm still listening to them) and was deeply disappointed when I got them home and listened for the first time. ProAc recommends about 100 hours of break-in time for these, but getting impatient after maybe 50 hours or so, I took them back to the dealer to inquire what was wrong with them. We hooked them up in the dealer's listening room, and the verdict was that to him they sounded tight and still too new. So I took them home again, played them a LOT over the next week or so, and I remember the moment when I started to hear their real personality. It was quite a revelation, a real "aha!" moment. From then on, I've been a firm believer in speaker break-in time. I imagine different designs behave differently and there's probably a wide range of break-in periods for various speakers. 1000 hours seems like an awful lot, though. (I'm old enough to remember the days when new cars couldn't be driven over 50 mph for the first 500 miles for fear of cracking the engine mounts. Maybe a similar principle at work here?)