I recently installed the US Spec iPod interface (crutchfield) and now have a clarity/volume issue with my factory XM? The XM still plays, but is very muffled. The interface comes with 2 harnesses that plug together and then into the cd changer port on the backside of the HU. I have the XM plugged into the passthru port on the new harness. Has anyone attempted this set up or done something similar? Can anyone help me figure this out?