Sennheiser HD820 Closed Dynamic Headphones 
 
The new audiophile standard
The critics said closed headphones could never sound as immersive as their open-air counterparts. They said physics would never allow it. To that Sennheiser simply said, “listen”. The HD 820 combines an innovative glass reflector and ring radiator transducer technology for a benchmark listening experience.
 
Completely closed. Outrageously open.
The HD 820 fuses our cutting-edge transducer capabilities with exceptional ambient noise attenuation, transcending the perceived limits of closed headphones.
 
Reflecting within
A closed back headphone able to produce the wide, natural sound field of an open one requires rethinking the directional characteristics of sound waves.
 
Fellowship of the Ring
An achievement in its own right, the 56mm ring radiator found in the HD 820 leverages the key benefit of a large diaphragm transducer—air displacement—without losing the rigidity that favourably impacts rest and response times.
 
Exhaustive engineering
The deep, almost magical stereo imaging of the HD 820 is the sum of the exhaustive engineering poured into it.
 
An Ergonomic Treat
The HD 820 delivers on long-term wearing comfort too, providing a listening experience as plush as it is immersive.
 
It's all about connection
As a centerpiece of your constantly evolving rig, your go-to headphones should offer the versatility to listen on your terms.
 
• Reference class open-back audiophile headphones
• Closed-back earcups
• 56mm ring radiator transducers
• German craftsmanship
• Detachable cable
 
 
 
Features
The new audiophile standard for closed-back headphones
56mm Ring Radiator dynamic transducer system
Concave Gorilla Glass reflectors deliver impressive spatial sound reproduction
Acoustic absorber system prevents frequency masking for unheralded detail
Ultra-ergonomic adjustable metal headband with inner damping element
Luxuriously comfortable microfiber ear and headband padding on key contact points
Developed in Germany and precision-built at Sennheiser’s state-of-the-art Ireland plant
Impedance: 300 ohms
Frequency Response: 6 - 48,000 Hz (-10 dB)
Total harmonic distortion: 0.02 % (1 kHz 1 Vrms)