The Sennheiser HD-820 is a closed-back version of the legendary HD800 headphones, and uses some innovative technology that makes them stunningly transparent.
Closed-back designs have historically suffered from unwanted resonances, while open-back designs, famed for their natural, transparent sound, can leak audio and let in ambient sounds.
For the HD-820, Sennheiser have used a glass outer cover paired with internal absorbers to eliminate resonances, giving audiophile listeners the best of both worlds.
Sennheiser's Axel Grell, Chief Headphone Engineer, says:
"The HD 820 is a game changer that delivers exceptional sound while insulating the listener from their environment. I consider them to be the most transparent-sounding closed-back headphones in the world."