Sennheiser HD - 414 stereo headphones colour black The Sennheiser HD414 changed the game in 1968. At the time, hi-fi headphones were all large and bulky, with locked backs, and the compact HD414 was the industry's first 'open air' on-ear (supra-aural) headphones. It saw, felt and sounded like nothing else and predicted the future direction of the headphone sound. Manufacturer: Sennheiser Model: HD 414 Year of manufacture: 1968 to 1990s Made in Germany