Having a bit of an issue, just installed my amp and components today, and for you to hear anything the gain has to be turned all the way up I know this is not correct, im running a Pioneer DEH P660 and a massive audio nx2 amp, I have the amp crossover set to hpf and the gain half way. everything is hooked up as it should be and all the settings on the deck are off and im letting the amp do the work,but you have to turn the volume up crazy high for it to even sound. my question is, the pre outs on the head unit is only 2v is this my problem or what could it be.thanks for any advice.