Help with setting impediance level for Polk rti a7 speakers


Hi guys I have the Polk rti a7s 8ohm speakers and I will be setting them up to A DENON poa 2800 200 Watts per channel at 8ohms and 400 watts at 4 ohms. My speakers are rated at 20 - 300 watts output. My question is how do I set the impedance level of my speakers from 8ohms to 4 ohms ? Sorry I’m new guys so yeah all help and tips are welcomed.

Thanks

Tony
daoki
The OP has a SS amp! Not a tube amp with multiple outputs! A Denon POA 2800! 
The POA 2800 has two sets of outputs per channel for driving two pairs of speakers.They are identical. Use either set with your pair of speakers.
So now you have Infinity Ref 60's! What happened to the Polk's? I doubt you have either!