multichnl

I am working on a two to three channel converter, kind of like dolby pro logic, but with a much faster attack and release time. Does anybody have any info of any of such systems in use, or the possibility of such a system. The final product would be in a throw away the headphones experience. I am fully aware of the holes remaining in the mixed left or right channels by subtracting the center channel. To further complicate things the main center channel masking information is not there to cover up the resultant subtracted non lifelike mixing of two audio sources. Obviously I am not talking about ambience but resultant discrete three channel output.