I have a 2002 Honda Civic and recently installed an Apline CDA-9853 head unit. It still has factory speakers.
I have a weird problem, such that when I connect an iPod to the unit (via a KCA-121B), on the vast majority of the songs I can't hear the lyrics.
I thought that this might mean my head unit is trying to output to more speakers than I actually have, but the radio sounds fine. I also thought it might be improperly grounded, (I connected the ground from the head unit to the ground coming from the car, rather than bolting it to the chassis). But again, radio sounds fine so that seems odd. Also, touching the metal back of my iPhone changes the sound (in fact, makes lyrics more clear) so that makes me think it's a grounding issue as well.
I thought I'd see if anyone has seen this before. I'm going to ground it properly today and see if that fixes it, but in the interim any light that could be shed on this would be appreciated.