I too had issues with loud pops and crackles from my speakers and tried just about everything except picking apart the speakers (hardware is scary). Eventually

I too had issues with loud pops and crackles from my speakers and tried just about everything except picking apart the speakers (hardware is scary). Eventually I did investigate the speaker internals and the culprit turned out to be a bad potentiometer on the back of the subwoofer; I bypassed it with a wire which fixed the problem completely.