Hey everyone i just inherited a Pioneer Premier deck, JBL500/5 amp and two RockFord Fosgate 12'' subs. Im having troubles getting decent sound while both subs are hooked up. I can make the system hit HARD with just one sub hooked up, but when both are hooked up sound quality degrades vasttttttttttly(i doubt they are hooked up right when they are both hooked up). What should i try? one freind mentioned something about bridgeing the voice coils??I have no clue what im doing, im some what of a car audio newbie... ANYHELP would be appreciated.