Anyone ever hook up 2 passive 8 ohm subs(with a seperate power amp) with a powered mixer? The mixer is a Peavey XR2012. It has 2- 600w amps. One powers the mains and the other powers the monitors. I'd like to hook 2 Peavey PV-118 passive subs at some point with a Peavey pv2600 power amp. Not sure if I need a crossover. The amp has a crossover feature that I'm not familiar with...The mixer has an aux send and a mono out. The mono is a blend of both channels and has its own slider to control it. Any Ideas??