bcschmerker4
That's bcschmerker4® to you!
I think the "fully open" in the quote is referring to sound not form factor, no?
Both, actually, Planar-magnetic transducers are by their very nature dipolar; Magnepan® has the rears of the Magneplanar® floor-standing speakers open so that the tweeters (and midranges where applicable) can function properly. With a planar-magnetic headset, the outside world hears what ye'd hear in the headset, only reverse-phase and softer.