I could go through the whole story, but instead I'll just say that I got some new speakers for my car (just two rear ones to replace the stock ones that died). They are wired directly to the CD player. The speakers are basically brand new, the wiring is anywhere from 1-10 years old, I really can't say. One speaker is absolutely perfect, the other will crackle when the volume gets too high. I don't think it's a bad speaker, but I suppose it's possible. Is it possible that the wiring is causing this crackle?