3 channel stereo music processor

I have 3 identical Tekton S-Lores for my LCR. What is the best (most flexible?) way to process two channel stereo music to originate the center channel signal for listening without the rear surrounds. I know everyone says to listen to two channels. But my set up is strange thanks to my wife's mandatory furniture arrangement. At this point for digital manipulation for a center channel I am using my Marantz receiver. I am considering a Harman Signature Citation 7.0 analogue processor as an improvement. Dose anyone have a comment on this or a alternative that is not crazy expensive?
The gold standard in synthetic 3 channel from 2 channel source processing is Meridian trifield. They have been doing this for over a decade so you can stay on the lookout for anything from a used 568 processor in the $800 range to used G68 or 561v4. If you need HDMI, you would need their HD621 box, which you could only use with more current processors.
You can also consider the Trinaural Processor.
Look into the VAS pre amp I, essentially a Harman Citation I model knock off. It take the original HK and updates it with current state of the art parts. I have one, and it does three channel very well, but is pricey