Don't ignore the fact it can take a solid hour for your other equipment to heat up as well...That may have been what you heard that you described so profoundly. I doubt a speaker broke in so suddenly, not to mention in such a short time...Break in time is long and slow, and usually so slow you don't notice the difference right away. I only noticed the difference when one random day I realized that all my equipment just sounded consistent every time I turned it on. So look for consistency in sound when looking for break it, thats how you define it IMO, not by looking for major sonic gains. Because essentially you get a very good idea for the sonic signature of ANY piece right out of the box. Although if I had to choose which link in a hifi system that logic applies to the least, it would be speakers. Give em time, lots and lots of time and patience. Don't fall for the banana in the tail-pipe either by leaving stuff on for weeks at a time either...Its unnecessary for most modern equipment today, they are designed to be turned on and off.