Rear driver side speaker popping

I starting having this popping noise in my Rear driver's side speaker after I installed 4 neon lights.  It happens every now and then and only happens when i actually have the head unit turned on.  Even the volume is set to zero, the popping is just as loud (always the same volume).  When I installed the neons, I screwed the relay switch right next to the knob that controls the volume of the subwoofer I have in the trunk.  Could this have anything to do with it?  But then again.... why would only one speaker have this problem?  I also removed the head unit a few times, so I had to remove the wiring harness behind the head unit.  I am thinking that maybe some wire in the harness got messed up...  Any ideas??

Yes, sounds very suspicious.  You probably have either a speaker wire or the speaker itself shorted to ground, or just too close to a neon tube or transformer.  Sounds like an induced noise to me.Support the12volt.com