“I will only say that his solution is not perfect nothing is but it is not a gadget improvised between other patented solutions... It is a bit more interesting ...”
You won’t say it but I will, the BACCH SP offers a near perfect rendering of spatial cues. The limiting factor is the source material. It’s easy to demonstrate. You can literally record a voice or musical instrument anywhere in the listening space with the BACCH in ear microphones -and compare the spatial accuracy that recording to the original source in it’s actual position anywhere in the room. The positioning is the n distinguishable if the system and room are good enough. What more could anyone ask than near perfect spatial reproduction?