Strange problem with L/R Balance and Bass

[neomits]

Here is the deal. I have a 94 Camry that about 6 years ago my dad and I replaced the head unit on for a refurbished Sony CD player the cost like $50. I think we were just wanting to add a CD player, I forget the original intention for adding it. Anyway, we got it installed no problem and on life went. I have since purchase the car from my dad and a few months ago he wanted to up the sound a bit for me. Neither one of us have any clue to the first thing about car audio, but he figured a good first step would be getting new speakers for the rear. We got those installed no problem but the sound wasn't anything breathtaking compared to the old ones. For christmas my parents got me a new head unit that could read MP3s off a CD and had an aux input. We installed that tonight and I noticed something strange once it was all said and done.

While adjusting the balance from left to right the direction is reversed. Ex: if I up the left side the right gets louder and vice versa. A bigger thing I noticed is that while adjusting the balance, the sound (noticebly the bass) became much clearer and better if I put all the sound on one side or the other. So basically I'm assuming/wondering if this is just a mix up of wires and which wires are mixed up. One thing to note is that we did not do any wire adjustments when we installed the new head unit for the second time. The rear connector fit in perfectly so we didn't have to change anything.

My dad thought that maybe if we switched the postives and negatives on just ONE of the speakers that would fix it but I'd thought I'd ask here first.

Sorry to be long winded. I'm a newb.

[cam2Xrunner]

Your speaker wires are reversed. Sounds like you wired the left side to the right speakers and vice versa.

[touringcamry]

I would make sure that the polarity of the wires is correct. If one speaker is reverse polarity, it will cancel out the bass of the other one. It sounds like you might have the polarity of one side reversed.

Are both your head units Sony? That's the only way that I can see you being able to install the new stereo without doing any other wiring. Even if they're both Sony, the pin-outs might have changed over the years but the stereos may still retain the same connector for some reason.

[neomits]

no the new head unit is a JVC. The polarity of one speaker is what my dad thought might be causing the problem. The problem with teh balance isn't as big a deal but I'm most curious about the bass. Would changing the polarity of one speaker hurt it if we are incorrect in this assumption.

[touringcamry]

You did ZERO rewiring, as in crimping or soldering, and all you did was plug in the connector for the JVC? It used the same on the back of the radio as the Sony?

If so, there's definitely a problem because the pin outs on the JVC are very likely to be different compared to the Sony. I'm actually surprised that everything even works. This causes one speaker to be reverse polarity and reverse the sides of your speakers. The bass sounds louder when turned to one side because both sides are out of phase and canceling each other out.