I want to combine the audio out put from my Garmin Zumo and my radar dectector and run them into my IPOD type ear pods. Both units have their own volume controls, and I am not concerned about a microphone out put. I am remembering something about it not being as simple as a "Y" connector. Is there a commercially available unit to do what I need? Or if someone can post a schematic of a diagram, I could make one up.