I replaced all the speakers, tweeters and the stereo head unit in 2004 LS 430 a few months ago with $1200 ken-wood DNX 893s navigational stereo unit. Every thing works fine except the fade from the front to the rear. As I fade it from the front to the rear, the sound fads out. there is no sound from the rear speakers. The right to left balance works fine and you can even hear the speakers in the rear with the left and right balance. I took it back to the professional installer that did the install and told that the unit was working correctly and that the premium mark levniston system amp has a two channel amp. He said in order to get the sound to fade front to back, I would to change the entire system using a 4 channel amp.Has anyone come across this and would know a less expensive way to correct the problem?You can call me @ 228 547 2111 & ask for GD. HELP!