RE: pg 158, thank you Audiofan1 about the upside down configuration you are running.
My M&K sub is 23" high, but on two stack of 8-1/2 x 11 paper reams on it's back is 19" high.
The 4" lower height when used in the center between the main speakers opens up the soundstage because of fewer reflections off the cabinet.
It sounds great.
Bottom firing woofer pointed towards me, front firing woofer pointed towards ceiling.
And as far as "The M&K" sound goes, the latest speaker claimed to be a "game changer" Bayz audio copies the push push - pull pull double driver concept.