Explain this to me. My old head unit had one sub/rear pre-out. I decided to use that port to amp my front comps. But it made them sound like pure shit. So I picked up a new head unit with front, rear, and sub pre-outs rewired my comps and now it sounds no shit 200xs better. I don't understand if my original head unit had pre-outs why didn't it sound just like it does now?