Audio Systems: speaker wiring, ohm voice coils, ohm subs

Question
I have a pair of 15 inch sub with dual 4 ohm voice coils is it possible to hook these up in series through the second voice coils to make them a pair of 8 ohm subs to maych the impedance rating of my amp

Answer
Yes, you can wire the coils in series or parallel.  If in parallel they will give you a 2 ohm load; if in series it will give you 8 ohms.

See these diagrams:

http://mobile.jlaudio.com/support_pages.php?page_id=161

You can google for others.  

And, you can sometimes get a better match by putting the two speakers in parallel for 1 ohm and bridging the output of the power amp - which can deliver more power when loaded into a 1 ohm load (usually for ClassD switching amps).  

Let me know the make/model of the speakers and the amp and I can give you further guidance - if you need...

Good luck,
Cleggsan