I put in an Aux jack (bought the cable and installed into the back my my non-nav head unit), and while it works well, I find I have to turn up the car sound to a very high level to get appropriate sound levels. This works fine, but of course when I switch back to AM or FM radio I get blasted with high volume. Do anyone else have this issue?

I'm using an audio cable from my ipod headphone jack to the aux jack. I've also turned up the ipod volume fairly loud.