weak speaker sound

Okay short and sweet.

All of my car speakers were factory. The two rear speakers sounded terrible, even crackly. Here's the real problem. My passenger side rear speaker had about half the volume as the driver side rear speaker. I thought it was just a speaker issue since it was so old. Well I replaced them and guess what the passenger side rear speaker still has about half the volume as the driver side rear speaker. Could the issue be with the radio? I was under the impression that the rear channel drove both speakers (driver side, and passenger side). If that's the case why would one side have a louder volume then the other? Would reversing the polarity to your speaker cause this type of issue (pos and Neg switched)? Could the factory have switched the polarity in the wiring harness?

I have a new radio to put in Ms. Roadie too, I'm just waiting on the install kit. I don't want the issue to still be there when I install the new head unit, if I can avoid it. Any idea on what might be causing this?

If those rear speakers are original they may be just worn out or dry rotted.To see if its the speakers just switch them and see what happens.

Here's a silly question, but have you adjusted the balance left to right and right to left? Is it centered? Could just be a weak channel in the old factory radio...

Change your radio.

I'd guess either the balance is not set correctly or the radio has a weak channel (in which case, I'd recommend replacing the radio)

Yeah I checked the balance and fade. That's how I can tell it sounds weaker than the other side.I found this other thread stating a similar issue. They replaced the radio and all was well. I just thought the rear channel drove both the speakers at the same time. I didn't know it would split the signal.