There's some clever custom technology, such as the dual-electrodes the HE90 have between the diaphragm that is the cornerstone of the push-pull principle, that go a long way to helping these cans use to produce their sound.
What a come-down for a cornerstone stalwart of Silicon Valley, which put the dynamic concept of Stanford University as feeding ground for technology greatness on the altar of a business culture that stood at the apex of American industry in the 1970s.