I should have mentioned before, and I did. I'm trying to create a live rack, not download tons of plugins. Besides I'm on PPC Mac. So regardless of what plugins you think I need, I'm 85% sure I can't run whatever you throw at me. Voxengo are all Intel only. That Universal Binary logo on the download page is a lie. Don't get me wrong, if I NEED a plugin for this then by all means let me know. But this should only be if it performs the right operation for what I'm after. Which brings me to another point, I don't think you understand my problem/request fully. Did you even try to recreate my problem in live to hear it for yourself? I know how to create and use a traditional m/s decoder, even without plugins. (which by the way, you will deprive yourself of the useful things that you'll learn about audio, and how it behaves, by not creating tools from scratch whenever it's possible. plus not to mention CPU budget[sometimes])
Thanks for the effort, I really do appreciate the gesture, but try to read more carefully next time. and/or try to fully understand the true nature of what a poster is asking before trying to solve it. Keep in mind though I'm only going off what garyboozy has posted since he seems to have tried/failed to make the requested rack, and I can't actually attempt your plugin suggestion myself. So if previously statements about not understanding my quarry are incorrect I withdraw them.
I'm not sure I follow. If you are talking about flipping phase to cancel out against a clean signal when you mention "...inverted and then compared and subtracted from Left and Right.", then that is possible realtime. I just can't isolate a pure mid signal that doesn't contain hard panned material. If you are talking about a whole other process, then would you please elaborate?