Wire each sub parellel, Each sub will only have 2 wires coming from it.
Just because is has 2 voice coils doesn't mean you'll have to have 4 wires coming from it.
______VoiceCoil 1 VoiceCoil 2
You Have:Black*____red
_________red*______Black
So wire: Black* to Black and red* to red, then have 2 wires
leaving the red and black. that will give you 2ohms.
P.S. don't pay any attention to the ____ marks.