hey guys i have a dual voice coil sub where the coils look like this: http://www.mcmelectronics.com/conten...s4/4000628.jpg
I have looked up plenty of wiring diagrams on how to connect a dual voice coil sub but none of them look like this. the terminals on each voice coil do not have + or - on them, how can i hook this sub up?

 

does it have a little-,+ sign stamped into the white piece of plastic like the old rockford fosgates?

 

Get a regular 1.5v AA battery, a piece of speaker wire and a few inches of electrical tape. This will enable you to test it and determine the polarity of the terminals. Tape the wire to the battery, one side of the wire to positive, the other to negative. Now take the negative wire from the battery and connect it to one of the speaker's terminals. Using the positive wire from the battery, briefly touch the wire (just for a fraction of a second) to the other speaker terminal, while watching for the motion of the speaker cone. If the cone moves outward when you touch the battery positive wire to the speaker terminal, then you've found the speaker's positive terminal. If the speaker cone instead moves inward, then that's the speaker's negative terminal. Since it's a DVC sub you'll have to do this twice, one for each set of terminals. Be sure to mark the polarity of the sub's terminals, as you don't want to wire a DVC sub with each coil out of phase relative to the other.

It's a good idea to do this even when there is an indication of the terminal's polarity, as manufacturers sometimes make mistakes, or mark the polarity for a different implementation than the user's intended application, so this way you'll be assured of the absolute polarity.

I should also point out that it's not intended to test tweeters, as the 1.5v and frequency produced could possibly damage them, and it's unlikely a person would be able to observe their motion anyway. It's a safe test for mids, woofs & subs, as they can easily handle for the short duration required.