Recently installed 4 brand new Infinity Kappa 6x9 in my truck. The other day I hooked up my Pioneer CD player that I have had in several cars over 13 years. And I've always had different versions of Infinity Kappa 6x9s hooked to it. They sound pretty good compared to factory speakers with the factory CD player but sound like crap when I hooked up the Pioneer. So either the newest versions are junk or the wiring in my truck is to small gauge to carry the extra power to the speakers and cause distortion.