@twoleftears
Your quoted the Positive-Feedback report
"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."
The bass solution decribed by Magnepan's top salesman as "unique" is not really so. All dipole speakers need EQ and since the cost of DSP fell down, it replaced discrete electronics. Siegfried Linkwitz (RIP) was a great proponent of dipoles, both in his corporate audiotech guru capacity and later as the "people's constructor". Go to linkwitzlabs.com His last design LX521 is a four-way and DSP controlled dipole. You can still buy the license and plans for $150. Total materials cost, if I remember correctly, ca 2k. His bass is a two-way V-frame, with two 10 inch dynamic cone drivers working in opposition. The phase is inverted on the back one, so the drivers work in push-pull configuration. That's what Wendell probably describes as "dual-dipolar". The LX521 is 10x cheaper and likely also 10x smaller than the 30.7 Magnepans. I would love to hear them in direct comparison.