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.
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?