New head unit brings crackle

Alright, i had an old piece JVC hooked up that was horrible so i decided to put it my pioneer from my jeep which is a really good head unit, just a few years old, so i cut off the wire harness going from the jvc to the honda off and sawdered the pioneer harness to the other end of the jvc so it could connect to my accord ... so once i did that i plugged it in and everything seemed to be alright except for a horrifying crackle in the rear drivers side speaker.. only that speaker none of the others, pretty much just crackles when it is loud or theres bass, its not a bad speaker though, its definatly distortion crackles..... any thought on what it could be? wiring for that particular speaker?, bad ground....? help me out i need this system up and running