yeah i understand that. i'd still prefer to use the preamp signal wires and control it myself. i hate how if you turn the volume up high enough, the amp attenuates itself. pisses me off.If you use the signal coming from the output side of the factory amp to the rear door speakers, there is no crossover to deal with, it is a full range signal. The factory speakers had a cap/coil crossover built onto the side of the magnet to protect them. I was using this signal for my LOC inputs and it rocked, but the OP's problem of the super high frequency was killing my tweeters as well. I am getting the parts together to build a resistor board to hook across the outputs of the Sony amp to see if it will stop that.