Im planning on buying shit from my paycheck every time i get payed from ebay,,, im gonna try and get two 15 inch l7 subs (square) buy that vented box for both of em and they sell some weird ass brand of amp that puts out 4000 watts... but ifi used that kind of amp,, would i need another car battery or some shit ,, compisator or some weird shit i have no clue about, lol.. right now im just used to one 12 inch cvr kicker,, but now since i got rid of my crown vic to my parents with 44k miles on it,, cuz i had to pay full coverage insurance on it and car payments ,,,, im finally gonna have a lot of spending money for a system etc.... but im wondering how do compinsators and extra car battery's work???