Sorry Rev, but you cannot hook those two units together. The Onyko NR515 does not have a set of pre-outs in order to use it strictly as a pre-pro. You are stuck with the Onkyo's internal amps. If it did have pre-outs, you would simply use RCA Audio Interconnects and would need 5 of them.
You will need an AVR that has pre-outs if you are intend on using the Emotiva in your system. These are usually the mid to high range models in manufacturers line-uos. Find the cheapest one you can that has a full set of pre-outs (not just subwoofer) that meets your decoding and room correction needs. Do not concern yourself about the AVR's power output - you won't need it. Good luck.
You will need an AVR that has pre-outs if you are intend on using the Emotiva in your system. These are usually the mid to high range models in manufacturers line-uos. Find the cheapest one you can that has a full set of pre-outs (not just subwoofer) that meets your decoding and room correction needs. Do not concern yourself about the AVR's power output - you won't need it. Good luck.