I actually think the first consumer model (HEV60) was released in the late '90s
HEV60 != Orpheus. Orpheus is the HE90 + HEV90. HE60/HEV70 is the "Baby O" and one of a few Sennheiser electrostat models. There's a thread on Orpheus in Summit-Fi for those interested.
Article is missing a lot:
- John Koss didn't actually design/invent the SP3 by himself, his co-worker/engineer Martin Lange is often credited with that (my understanding is that John Koss is like the Steve Jobs of headphones; Koss Corp is not a one man show is the point).
- Eugen Beyer invented stereo dynamic headphones in 1937, the Beyerdynamic DT48. They are likely to end production this year due to reported supply issues.
- Orpheus came out in the 1990s and cost nowhere near $40,000 (that's higher than any used gouge I've ever seen); I think actual MSRP was something around $9500.
- Should also mention the Koss ESP/6 or the first STAX (SR-1 I think), as the first electrostatic headphones (it's contested as to which one is actually "first" - and they're fairly different designs too).
- Could also mention Sony's invention of woodies, with the MDR-R10, as well as the bio-cellulose drivers they developed for them. In fact, there's a lot of Sony contributions that should be mentioned.
- The significance of Grado and Sennheiser on the development of the high-end headphone market should also be mentioned on some level.
- Ultrasone and Audio-Technica should at least be mentioned somewhere (they've both contributed a lot, AT more than Ultrasone (AT also has some 30 years on Ultrasone)); Yamaha and Toshiba as well, for their isodynamic and electret headphones.