If it is a crackle that occurs from being jarred around, it is obviously a bad connection somewhere around the speaker or somewhere in the wiring. It is intermittent because sometimes the connection is made fine and other times not.The trick is finding out exactly where the problem is at. It could be at the solder point on the speaker, in the speaker connector (assuming it is a factory speaker), or a break in the wiring somewhere. The best way to determine the problem is to lay in the trunk with the radio on and move the wiring and try to zero in on the problem area.
