Car stereo speaker terminals - which is + ?

Factual Questions
1

I’m hooking up some old Infinity Kappa car stereo speakers and I can’t tell which is the + terminal. The only difference I can tell is that one tab is wider than the other. Both seem to follow the same path through the cone to the tweeter. Is there some kind of standard (wide is +, thin is -; right is +, left is -) or do I have to experiment?

2

It actually doesn’t matter, as long as you’re consistent all around. The wire should have some kind of marking or color coding; as long as you put the same side of the wire on the wider terminal on all the speakers everything will be in phase, assuming these are going to be the only speakers in the car. Now, if there are existing speakers and you’re adding these, say, as a new front pair it gets a little more tricky. You may have to experiment a little to see which of the two possible ways sounds best. If you can’t tell the difference, it doesn’t matter.

3

Really doesn’t matter that much. If you’re just setting up two speakers, pick either terminal as the + and do the same on the other speaker. This way, each speaker will be pushing or pulling at the same time.

If you have one pushing while the other is pulling, they’re “out of phase,” and you’ll have severely reduced bass output.

Otherwise, you’re not going to damage anything by reversing the wires to a speaker - the real world effect will be more like “Sounds good” or “Sounds funny.” If it sounds funny and the bass is weak, reverse the wires at one speaker.

4

Easy test, put a battery to the terminals, and watch which way the cone moves. A battery is DC so once the power is applied, the cone will stay in maximum deflection. Figure out which terminal pushes the cone “out” (towards you) when applied to the + side of the battery, and call that positive on all speakers.

Then apply Q.E.D.'s consistency attitude in your wiring.

5

Be very careful when you do this not to energize the coil too long. An alkaline battery can easily push enough current through to do some damage if left on long enough, particularly on small, lower-wattage speakers.