Play the same tune and take the covers off the speakers and observe the cone. If it looks like it is trying to throw out too far you might just be bottoming out. This will sound pretty much like what you described.
Trouble in Paradise with my Danes?
Do I have a major problem? I was listening to some music (with heavy bass) on my Satellite through my new Danes tonight when I encountered trouble in paradise (and I wasn't even playing them loud! My 85 watt/channel Denon wouldn't push them that loud even if I had it blasted and I didn't even have the volume above 0). Anyway, the heavy bass resulted in some cracking sounds coming out of the lowest midrange of the left speaker, but there was no problem with the right one. I listened to some other channels with heavy bass (even some rap) and did not hear the same problem, but the bass wasn't as deep as when it occurred. Do I have a blown speaker? or did I go below their range? What does it sound like when you go below the capability of a speaker?