I had a small clicking or ticking type noise in one tweeter a while back, I swore it was blown so I pulled it all apart and sent it in, they tested it and said it was fine, BUT sent me a new one just because they wanted me to be happy.... I put it in and the same thing happened, I checked all the wires everythnig was good, so I swapped speakers cables and it moved to the other speaker, I pulled the cable apart and the only thing I found was some splayed wires in the end of the banana plug, I soldered the end and dremmeled the excess off, noise was gone, about 3 months later the other cable did the same thing, I fixed it the same way and never happened again... It was driving me crazy for a while though, but you cant have a stereo with no wires...