So I'm an audio tech. But most of my knowledge is limited to stage mixing and set up. So how does car audio work? I'm mostly confused on amps.I'm looking to put 4 tweeters and either 2x15" subs or 4x12" subs. I know I'll need a pretty big amp. But how many channels? Anything else I need. I know I'll need a faceplate and stuff like that. So explain it to me please? 