Sennheiser HD 820 Over-Ear Closed-Back Wired Headphones - 507435

Sennheiser 507435 HD 820 Over-Ear Closed-Back Wired Headphones

The Sennheiser 507435 HD 820 wired over-ear headphones combine a closed-back design with 56 mm ring-radiator drivers, concave Gorilla Glass reflectors and passive noise isolation for spacious, private listening. With 300-ohm impedance, they include both 6.35 mm unbalanced and 4.4 mm balanced connection cables for compatible audio equipment. Microfiber ear and headband padding, an adjustable metal headband and articulating earcups support sustained listening. Designed for audiophile and critical listening, their acoustic absorbers and angled drivers help reveal recorded detail and positional cues while preserving the focus of sealed earcups.

Key Features

Closed-Back Design for Private Listening

Closed, circumaural earcups surround your ears and provide passive attenuation rated at up to 25 dB. The seal helps limit incoming distractions and outward sound leakage, keeping attention on the recording during critical listening tasks or a private music session. The acoustic design brings a spacious presentation to an enclosed headphone.

Reflecting Within: Gorilla Glass and Acoustic Absorbers

Concave Gorilla Glass reflectors address the direction of sound waves so sealed earcups can still deliver a wide, natural sound field. Acoustic absorbers complement this reflector approach, supporting detailed reproduction without requiring an open-back enclosure. Together, these elements challenge the idea that closed headphones must sacrifice a sense of space.

56 mm Ring-Radiator Drivers

The ring-shaped driver is secured at both its inner and outer edges, with a voice coil acting through a V-shaped groove. This construction works with damping to support controlled reproduction, while individual transducer testing helps keep performance consistent. It is an acoustic approach built around precision for listeners who want to hear into their recordings.

Angled Drivers for Positional Detail

Developed in Germany and precision-produced in Ireland, the design pays particular attention to stereo imaging. Angling the drivers helps preserve positional cues, allowing you to follow voices and instruments within their recorded environment. That spatial focus supports critical listening to the placement of different elements in a recording.

Microfiber Padding and an Adjustable Fit

Microfiber padding cushions the ear and headband contact points, while each earcup pivots on two axes to conform to your head. An adjustable metal headband with internal damping lets you refine the fit for sustained listening. The composite headphone construction weighs approximately 360 g without the connection cable.

Balanced and Unbalanced Wired Connections

Choose the included 6.35 mm unbalanced cable for compatible headphone amplifiers, DACs and receivers, or the included 4.4 mm balanced cable for equipment with a matching balanced output. Both detachable leads are 3 m long, giving you reach from equipment on a shelf, desktop or studio setup. Their low-capacitance, impedance-matched design supports integration into a dedicated listening system. An optional XLR-4 balanced cable is sold separately and is not included.

Features

• Closed-Back Passive Isolation
  Helps keep room noise out and music from escaping into your surroundings.
• Concave Gorilla Glass Reflectors
  Support spatial sound reproduction within sealed earcups.
• Acoustic Absorber System
  Complements the reflector design for detailed listening.
• 56 mm Ring-Radiator Drivers
  Individually tested transducers support consistent reproduction.
• Angled Driver Placement
  Helps maintain the position of voices and instruments in recordings.
• German Development and Irish Production
  Combines development in Germany with precision production in Ireland.
• Adjustable Metal Headband
  Incorporates internal damping and lets you tailor the fit.
• Microfiber Padding and Dual-Axis Earcups
  Soft contact surfaces and articulating earcups support extended listening.
• 300-Ohm Wired Design With Detachable Cables
  Includes 3 m leads with 6.35 mm unbalanced and 4.4 mm balanced plugs.
• 6 Hz - 48,000 Hz Frequency Response (-10 dB)
  Reproduces a broad frequency range for critical music listening.
• Low-Distortion Reproduction
  THD is specified below 0.02% at 1 kHz and 100 dB.
• Included Storage and Care Accessories
  A storage box, microfiber cloth and instruction manual accompany the headphones and two cables.

Footnotes:

Performance figures are based on manufacturer testing under specific conditions and vary with the listening environment, settings and use.