ok i think one person should be helpin your. lets start from scratch!
turn the gain, freq, and eq all the way down on your amp. pop in a 50Hz test tone in your CD player and turn in up to 3/4 of max voulume. now start truning the gain on your amp till u get around 31 volts. u can go over a touch. now reconect the sub to the amp and play some music and lower volumes and turn the FREQ all the way up. now listen to the sub and not the speakers, turn the the knob down till u stop hearing voices. ruffly 1/3 of the way up. also the bass and treble on your CD player should be off, same thing with any other settin on your deck like bass boost or loud