A brief trip back in time:
I've heard most of the world's best headphones, but somehow missed the Sony MDR-R10.
Only 2,000 were made. Production started in 1989, and at $2,500 a pair, it was the most expensive headphone in the world.
The MDR-R10's 50mm "Bio-Cellulose Dome Diaphragms" are credited with producing the
headphones' superclear treble and oh-so supple bass. The headphone also sported real lambskin-covered ear pads, and the large sculpted ear cups are made from aged wood from
Zelkova trees. Sony did make a few other headphones with Bio Cellulose drivers -- the MDR-CD3000, 1991, MDR-E888 in 1995, MDR-CD1700 in 1996, and the MDR-CD2000 in 2000 -- but those headphones never attained the stature of the MDR-R10. No, it's never just one thing that makes the great ones great, it's the whole design.
So the question is raised: If Sony was clever enough to design a world-class, uber-audiophile headphone back in the day, why can't they do it again? Or make something almost as good and sell it for a lot less? I really don't have a clue, but the MDR-R10 may have really been the Holy Grail, at least as far as dynamic headphones go.
2016:
I want me some Bio-Cellulose Dome Diaphragms, please or will this new dome beat it?
footnote: content taken from http://www.cnet.com/news/sony-mdr-r10-the-worlds-best-headphone/
final thoughts: 27 years later - these are 200.00 cheaper than the MDR-R10