I just installed a used Alpine chm-s600 cd changer and a Peripheral adapter that was taken off a 2000 Accord. The adapter has the blue plug that fits the back of my stock 2002 HU, but when playing a CD in the changer the sound is very muffled on the left hand side. When I move the balance all the way to the right, it sounds fine, but when I move it to the left, you can barely hear the singer's voice or most instruments. This is true front and back (Lucid's speakers) and with different CD's. If I play the radio or in-dash CD, everything sounds fine. Is there a way I can test the adapter and or CD-changer?

Thanks