I was wondering if anyone know's of a tool that would let me find out which speaker wire would be positive or negative?

The speaker wires aren't color coded so its a guess game when I run new speaker wire into the door.

 

There are many tools that will let you do this, but what most people do and is the cheapest is to use a 9 volt battery. When you hook up the speaker leads to the battery the speaker will either move forward or backwards. If it moves forward the positve and negative are correct. If it moves backwards the positve and negative are reversed.

 

This is the easiest way. Its referred to as "pop testing"

 

So just try to to run the cable from the speaker to a 9v batteries positive and negative terminal and see what happens?

 

You should have the ends already exposed and hooked to the speaker. From the speaker take the wire, split it and strip the ends. Take the 2 ends and touch one to the pos. and one to the neg. on the battery. You will here a faint "pop" and you can see whether it is pushing out when "popping" or is moving in. If it pops out you have them correct. Typically as a standard I try to use the thread on the speaker wire with the writing on it as my positive. Coming from the power source (i.e. head unit) typically the lighter colored (or pastel for factory wiring) wire is positive and the darker (i.e brown) is negative. But your best bet is aquiring a wiring diagram for that.

You can also you a AA, since they are often more common and easier to find around the house.

 

ok, cool thanks for the info

 

Using a 1.5v battery will be easier on the speakers and won't push or pull it as much as a 9v. Just don't use your car battery!

Phase or polarity is relative, and I've seen different speakers label the positive and negative terminals in opposite fashion. It is of critical importance that all of your speakers are wired in the same polarity or you will get bass cancellation and it will sound horrible. If you've ever sat between a pair of speakers that were wired out of phase, the bass is diminished but the stereo image is completely destroyed and screwed up. If you have all but one speaker wired correctly, it won't be as noticeable but it will make a difference.

 

+1

 

qqqqq

 

what he said

also
buy a volt meter it will be very useful if your a DIY audio guy or gal

 

This is true, try looking for the wire with the black strip too. That's always or should be the negative.