I have an Eminence Cooperhead that I wanted to break in. So I get a frequency generator on my computer and I set it for 60hz. I come out of my soundcard into a Crown XS500 power amp. From the Crown I go into the speaker which I have sitting face up on my desk. I turn on the signal generator and turn up the power amp until I see the speaker working nice and hard. It's loud but by no means deafening. I go take a shower and then go downstairs to do some reading. All the while I hear the speaker humming merrily away. Then I don't. I go upstairs and find that the speaker is still vibrating but not at the low 60hz frequency. I load it into a guitar cab. No bottom end, all treble. I guess I over did it. My question is, what exactly did I do to it? There is no visible damage. Is there any repairing it?