So, I've searched the forum and there are some awesome DIY on the rear speaker replacement but I can't seem to find the answers to the following questions.

In the 2005 Z, for the rear speakers, if I am using the stock wiring, which one is positive and which one is negative? I don't have a volt meter and I was wondering if anyone could help.

Also, when I install the speakers (Polk DB651s) regardless of how I wiring the speakers, the sound is scratchy, any one know the reason?

Should I just buy and OEM replacement speaker or can I actually get these Polk speakers to work on the stock system? I've upgraded the stereo, so they should be getting plenty of power. My car is in pieces now

 

It's never a good idea to use stock speaker wiring imo. From my limited experience, scratchy sounds from from a loose connection somewhere. Are you sure you connected them properly?

 

I can't say that I connected them properly, because I couldn't figure out which one is a positive and which one is the negative. I assume that if someone can tell me that, then I can get a better connection.

I agree that it's not a good idea to use the stock speaker wire, but I didn't want to add to the hassle of replacing the back speakers and I went for something that was just a little better than OEM.

So, I guess the big question.......

At the actual speakers in the rear of the car, where they plug in to the OEM speakers, which wire is a positive and which is a negative?

Chances are tonight I will just buy a volt meter and test this myself, but I really thought this information would be easier to find, but it definitely isn't.....and I am pretty good at using Google

 

I havent looked at a stock speaker, but some may have a red dot near the speaker terminal and that one would be your positive.

 

ur magnet might be touching something.

 

remove factory speaker , cut off factory plug where - & + speaker wire terminate at the plug leave 2 " of speaker wire attached to the plug , strip a tab bit of speaker wire off of the 2" you left , take a 9 volt battery touch the speaker wires to the 9 volt , if the speaker moves in your wiring as it touches the 9 volt is backward, if the speaker moves out than the wiring is touching the battery correct

when speaker moves out note what color wires are touching - & + terminal of 9 volt as you have it correct when speaker moves out

 

Thanks for all the help, I read about the 9V battery trick, but I never thought about using the stock speaker with the wires attached to find this out. That's pretty clever. Also, with the magnet touching the edge, could be the issue.

I appreciate all the solid help.

Thanks