I'm going to stick to my opinion it is a lunatic design.
A sealed enclosure needs a driver Qts, of above 0.5 and a horn below 0.5, preferably below 0.3. So a low Q driver sealed at the back will have a high F3, and a high Qts driver will not properly load the horn.
That speaker makes no sense to me at all.
To be fair, PWK designed this contraption in 1946, using a slide rule and trial and error, in a tin shed in Hope, Arkansas. Design per t/s parameters didn't become a thing until the 1970's. It is what it is, and for it's time was innovative.
To the OP and the noob king, this Martion Orgon company has poached a design that harkens back to the primordial days of home audio. It does a couple things exceptionally well (high sensitivity, low IM distortion...really two sides of the same coin, as it turns out they're inversely proportional). Think of them as something like a Model T Ford that gets outrageously good gas mileage.
