Thinking about it, I really may just be stupid because I think I'm putting the player in the output but there is no RCA input. But I can't seem to get my MP3 player to play with my cars speakers, only the subs and amp. The module uses RCA cables and a headphone jack. So I just used some Y connectors and "spliced" it. But like I said I only get sound through my subs. Now, besides buying a headunit which has an output/input. How am I supposed to make this thing work with my 4 speakers and two subs?