Earlier this year I purchased a pair of older Avatar 410 cabs with the kappa pros in mint-y condition. After playing with them for a while, I found what I thought was one speaker squeaking. So I called Dave at Avatar and he told me that its possible that one of the voice coils may be rubbing, so I was all set to buy new speakers from Dave when I thought to check all of the screws first. Most of the speaker screws were loose, so I tightened them up and it still squeaked. Then I tightened up the handle screws and they were loose but not by much. Low and behold, the squeak was gone!