Something that has been in the back of my mind for some time, especially with respect to headphones (but also with speakers) is the idea of a design that simply avoid the various design tweaks needed to shape frequency response, and relies purely on active correction. So I wonder of
@Dan Clark might be just the right person to ask. This strikes to the question of open backed versus closed.
Clearly open backed are advantaged by essentially radiating the back of the driver out into a near infinite void. With the energy never to return. A closed back design needs to manage stored energy in its multifarious forms. But both designs also have sculpted frequency responses designed to mimic the wearer's HRTF and manage interaction with the pinna. This means some interesting tweaks and frobbing with the mechanical and acoustic properties of the design in ways that might not be the best answer for best possible performance. One wonders if a closed back headphone that was designed with as perfect damping in the rear cup as possible could be made and its frequency response shaped with a bespoke set of equalisation parameters. Within the constraints of the size of the cup one might be able to achieve the best of both worlds. No stored energy issues, really good bass, really good isolation.
It seems that the market is not quite ready for such a product, but is very very close to the point where it might be. Most of the ducks are lined up. So maybe. Perhaps Dan could make an Æon DSP and test the waters. I would by one.