If the sub is stable for a 4ohm MONO load (which I'm almost positive it is, post the model number so I can verify), wire them like so:
(1) On each sub, wire the voice coils in parallel. Connect the one of the (+) leads to one of the (-) leads on the same speaker. Now, each sub will have an impedence of 8ohms.
(2) Wire the subs in parallel to the amp in bridged mode. The positive lead on the amp should go to the positive lead still left open on each sub. The negative lead on the amp should go to each open negative left on the subs.
(3) The subs are now making up a single 4ohm impedence circuit. This should draw the most power out of the amp. Theoretically, each sub should be receiving 300w.
(4) Make sure you're running your amp in bridged mode. Check the manual. You usually use a single positive lead and a single negative lead on the amp. It converts two separate channels into one channel.
(5) Enjoy your subs!!!
