I accidentally purchased a $400 Center Channel speaker with 4 ohm impedance, forgetting my Denon AVR-X4500H only supports 6 and 8 ohm impedance. How will this negatively affect my audio quality? Is there a a piece of hardware I can add to add impedance? Hopefully one the goes on the speaker wire and doesn't require opening the speaker cabinet. Am I better off selling my speaker and using the money to buy a similar one with 6 ohm impedance?