getting new Mixer: Mackie???

[Monolithent]

Had a few moments to look at the manual for the Mackie M1400i you have.

Here's what you do........run stereo into the 1400 just like you already are from the 2 main outputs on your mixer. The 1400 has a THRU connection (basically two outputs that aren't amplified and are identical to what's going into the 1400). Get two XLR cables and run them from the THRU connections on the 1400 to the RMA 800 inputs. And then run out of each amp to your speakers as you already have been doing.

Or you can get a crossover.

Good luck with it. Gimme a yell if you need help.