Got a pair of 3-way infinity kappa 6x9's in the back of my car, 4" 2-way kappas in the front. The rears are starting to crackle when the volume is up even a little bit, I gotta listen to stuff real quite now, like quite enough that your mother wouldn't even say anything about it lol. WTF causes this? These speakers where like 300 bucks lol. Does it happen to all speakers eventually or only if they are abused or what? I know I am not driving them properly, they aren't amped and I know they should be. They are rated like 110w RMS each and they are getting 45, is that what killed them? Is it really necessary to amp speakers like these?