Hey guys, I just joined Car Audio in sight for help. I have a 1989 Chevy Silvarado, with a planet audio 1800 5 channel amp, and a 10inch pioneer under-seat sub, also 2 4x6 planet audio 3ways in the front. Im not too impressed with the sound. My sub seems to stay at one volume even if I turn the amp up (im new to audio and have no clue how to "tune" a amp) I would like help on why this is happening. And I need some suggestions on a 4x10 rear speakers. I listen to metal but occasionally listen to dubstep and rap. I would like to have a really sharp sounding speakers, picking up good highs and lows. I know you might get annoyed by my questions, sorry im new to audio and would really like to gain some knowlage please help!!