What's wrong with my almost new speakers?

I purchased a pair of new speakers less than 2 yrs ago. They sounded just fine to begin with, but within 1 year they became "irratating" after a short listen. I have purchased new speakers since then from Focal and Harbeth, and both of these pairs sound wonderful. What's wrong with the speakers from 2 yrs ago? Bad crossovers? Bad drivers?
We do not listen to music at loud levels.