@pirad Description of the Magnepan subwoofer accompanying the "condo" 30.7.
"The bass unit was about 3 feet tall and about 1 foot wide. The cabinet or structure consisted of a V shaped open baffle with 8 total drivers—4 vertically mounted dynamic cone woofers on each side of the V. These woofers were approximately 6.5 inches in diameter. Though there has been several dynamic cone dipolar designs attempted before, Wendell commented that this was a unique design that utilizes DSP and would eventually be patented. Yes, I said DSP!
Though Wendell used the term "dipolar" for the bass units, I was told that the key design elements were the dual array and open baffle mounting along with the use of DSP. With this in mind, he also used the term "dual-dipolar" for the entire system to reinforce that this is a unique overall configuration and yet it still has the ability to be competitive with an all magnetic dipolar design."