common background separation

[atenzor]

@Trebor

assuming you are still reading this topic, just one last thing to ask you.

Since I never used this sort of method before and I used a lot of methods, I was wondering about the IDEA behind it.
I mean you mentioned combining two left channels and two right channels and for each apply center-isolation. But why? what is the reasoning behind doing it this way? did you come up with this or did you saw this method somewhere before?

thanks