How bad is the damage to my speakers?

So I bought a Cambridge Audio Azur 851D DAC that can also double as a preamp. While hooking it up to my system (B&W CM10 speakers and Parasound A21 amp), I made a colossal mistake. While streaming music via my iPhone, I had the iPhone volume turned all the way up, and I mistakenly disabled the preamp/volume control section on the 851D, in other words the speakers started blasting at full volume. Obviously, I panicked and it took me at least 5 - 6 seconds to figure out what was going on before I could shut down the 851D. My ears are still ringing and I probably should get them checked out.

My question is how much has this mishap damaged the speakers? I've noticed that the bass is a bit looser since then and the slam is less obvious than before. Is this an expected result? What recourse do I have at this point? The speakers are only 3 months old. Does anyone know if the speakers have any built-in mechanism to protect against such stupid accidents? I'm just livid at myself right now.