Bi-amping with Marantz 2285B

You should be able to connect two speaker cables from the Marantz speaker out 1 and out 2 and connect one set to the upper posts and the other to the lower posts of the speakers. As long as your Marantz can turn on both speaker one and two at the same time, it should work. Not sure if this will yield any change in sound, I personally would not bother. Your speakers are 8 Ohm and only 88db efficient, not a high efficient load but should be OK. 

It's a SS receiver with phono ins, aux ins, tuner, etc.,  and two pairs of speaker outs.

Is your maranta a receiver/integrated amp or a pre amp?

All you need to do is use a splitter on your normal pre amp outs. The crossover in the speaker tells the amps what to do. One stereo amp for left and right highs and one amp for left and right lows. I run a SS amp for lows and a tube amp for highs. Sounds smooth!