These folks are rather clearly a lot more sophisticated than "What's a Fletcher Munson Curve?"
In all likelihood they've had to tune things to a very fine degree, both in dsp and in the physical driver design. Because these are used in the near field, with the specific intent of leveraging acoustic cues from the outer ear, they won't be able to just reuse a reference curve developed for headphones or speakers.
They have a dummy head for binaural measurements, so this isn't a particular hard thing for them to calibrate.
If open-back headphones are not closed-back headphones, these off-ear headphones are not open-backed headphones — there seems to be as much differentiation to me.
And they didn’t say “revolutionary” or similar anywhere, as far as I can see.
You're, if I can be frank, wrong. The difference between the two different types of headphones is the amount of isolation the headphones provide. Open back headphones provide minimal, if any, isolation. Closed back provide significant sound isolation. This difference was outlined by a sibling comment which was sadly downvoted.
These are simply open backed headphones that use a different method of setting the distance between the driver and the ear. That's all.
This is the first time I'm aware of anyone has used this class of driver for headphones, and they have novel properties that support their idea of a spaced nearfield monitor rather than an open or closed back cup.
For "off-ear" headphones there are only 3 different ways to build them: closed, open or half-open, solely based on amount of air flow given to a driver (and the type of driver doesn't matter).
These are quite different from other open-back headphones such as HiFiMan, etc.
There's no seal on or around the ears like traditional headphones. Additionally, they sit much farther away from the ears compared to existing headphone designs.
Open ear headphones have no seal, either. The parts that contact your head simply set the distance between your ear and the driver. This is simply open ear headphones being held a set distance from your ear in a slightly different way. Anything else is pure marketing.
No, these are quite different. They transition from axial motion to radial motion at around 3khz. The source in the near field is quite a bit different from an open back headphone driver.
In all likelihood they've had to tune things to a very fine degree, both in dsp and in the physical driver design. Because these are used in the near field, with the specific intent of leveraging acoustic cues from the outer ear, they won't be able to just reuse a reference curve developed for headphones or speakers.
They have a dummy head for binaural measurements, so this isn't a particular hard thing for them to calibrate.