AR9 Sub Use

I am finishing my AR9 rebuild, 4 woofers due from recone shop next week, YIPEEEE!

I plan to discontinue the use of my faithful Velodyne CT1500 sub and use the sub features of the AR9's.

I plan on a single (on screen adjustable) RCA sub out from my HT receiver. What would you suggest from the single sub out RCA of the receiver to the L/R biamp woofer inputs of the AR9's
Thanks All!