This is about the crosstalk cancellation (XTC) algorithm implemented in BACCH. Thanks for sharing. If the XTC-induced tonal distortion during playback with only two loudspeakers is the main factor affecting the perceived 3D sound effect, would reducing crosstalk (XT) be the ultimate solution? If so, one could use two mono amplifiers or a true dual-mono amplifier to greatly reduce crosstalk and enhance stereo imaging.
However, complete elimination of XT is not necessarily beneficial. If the sound reproduction had no crosstalk, as in pure binaural audio fed into headphones without processing, the outcome can be unnaturally wide or even disorienting. Simply put, our ears are accustomed to some crosstalk in real life—sound from the left still reaches the right ear, and vice versa. From this excellent article, I am not sure how Professor Choueiri addresses this aspect in an optimal way.
In addition to the aforementioned electrical XT, there is also acoustic crosstalk to consider. I have already addressed this with speaker separation, toe-in adjustment, room treatment (in process), and reflection control. Beyond that, it seems the use of digital filters such as BACCH will be the route but what else?