Raul,you did not do your homework -:)
Since I assume you are still trying to convince "me" about the "why" I should add a second sub in my own set-up....
Well G.Morris "is" someone I like,and trust.....BUT....he has a completely different speaker/presentation/configuration/room than me.Also,my own speaker goes lower in freq(with more low freq weight than the "superb",but a bit rolled off Maggies.I know them extremely well,so I post from experience,not theory.
Besides -:)....I absolutely "love" my current "full range" sound.No complaints,other than still waiting for my table(coming on the 24th).My new Phantom and Orpheus "need" to play some vinyl!!
Raul,there are some times(I say this from experience)when things can be screwed up,if taken too far.In my room,with my equipment,and the "still surprising me daily" Ascent MK-II's I feel(from listening observation)that I can too easily make a mistake by adding a second sub,for "only" the lowest frequencies.Which(btw) I can "do" quite well,as of now!
Hope you can understand my point of view.
Best regards.