The Sennheiser HD820 is a closed-back audiophile headphone that pushes the boundaries of what was previously considered possible in this product category. Designed and manufactured in Germany, this high-end model stands out for its innovative approach and exceptional sound quality.
Design and Conception
The HD820 immediately stands out with its unique design. The outer shells are made of concave glass, a feature that is not only aesthetic but also plays a crucial role in the acoustic performance of the headphones. This glass panel covers the “Ring Radiator” transducers, a proprietary Sennheiser technology renowned for its sound quality.
Materials and Finishes
The attention to detail and quality of craftsmanship is evident in every aspect of the HD820:
- Robust metal headband with internal damping
- Handcrafted microfiber ear cushions
- Silver-plated OFC (Oxygen-Free Copper) cables
- Gold-plated connectors
These material choices not only ensure durability but also contribute to the overall sound experience and user comfort.
The Challenge of Closed-Back Headphones
Traditionally, closed-back headphones were considered inferior to open-back models in terms of sound quality, especially for audiophile applications. The HD820 aims to challenge this paradigm by offering a listening experience comparable to the best open-back headphones while retaining the advantages of a closed-back design.
Glass Reflector System
The key innovation of the HD820 lies in its glass reflector system. The concave glass serves multiple functions:
- It reflects sound waves from the back of the transducer towards an absorber.
- This reflection minimizes unwanted resonances.
- The process simulates the effect of an open-back headphone, allowing sound waves to be “vented” in a similar manner.
Ring Radiator Transducers
At the heart of the HD820 are Sennheiser’s Ring Radiator transducers. This technology, already proven in other high-end models from the brand, is optimized here to work in synergy with the glass reflector system.
Acoustic Performance
The HD820 offers an impressive frequency response:
- 12 Hz to 43,800 Hz (-3 dB)
- 6 Hz to 48,000 Hz (-10 dB)
This wide frequency range allows the headphones to faithfully reproduce the subtlest nuances of music, from deep bass to crystal-clear highs.
With a sound pressure level (SPL) of 103 dB at 1 kHz for 1V, the HD820 is capable of delivering significant volume while maintaining minimal distortion.
The HD820’s impedance of 300 Ω is typical of high-end audiophile headphones. This high value generally requires the use of a dedicated amplifier to get the best performance from the headphones.
Listening Experience
The HD820 is designed to offer an exceptionally wide and natural soundstage, a feature generally associated with open-back headphones. This performance is all the more remarkable for a closed-back headphone.
Sound transparency is one of the HD820’s strengths. The headphones are capable of revealing the smallest details of the recording, offering a faithful and precise reproduction of the music.
Unlike open-back headphones, the HD820 offers excellent sound isolation. The microfiber ear pads effectively reduce ambient noise, allowing for total immersion in music without disturbing the external environment.
Comfort and Ergonomics
The HD820 features a circumaural design, meaning the ear pads completely surround the ears. This approach contributes to sound isolation and enhances comfort during long listening sessions.
Weighing 360 grams without the cable, the HD820 is average for high-end audiophile headphones. The weight distribution and headband design are optimized to minimize fatigue during prolonged use.
Its handcrafted microfiber ear pads offer several advantages:
- Increased comfort due to their softness
- Improved breathability compared to leather
- Durability and ease of maintenance
Connectivity
The HD820 comes with several connection options to suit different audio equipment:
- 6.35 mm stereo jack (asymmetrical)
- 4.4 mm Pentaconn stereo jack (symmetrical)
- XLR-4 connector (symmetrical)
Detachable Cable
The HD820’s cable is detachable, offering several benefits:
- Easy replacement in case of damage
- Ability to use aftermarket cables to customize the sound
- Simplified storage and transport
The standard cable provided with the HD820 is 3 meters long. This generous length offers appreciable freedom of movement when using the headphones with fixed equipment.
Compatibility and Amplification
With its 300-ohm impedance, the HD820 requires quality amplification to reach its full potential. Portable sources like smartphones or MP3 players are generally insufficient to properly power these headphones.
Sennheiser specifically recommends using the HDV 820 amplifier with the HD820. This amplifier was designed in tandem with the headphones to offer optimal synergy.
Accessories and Presentation
The HD820 comes with a complete set of accessories:
- Connection cables (6.35 mm jack, 4.4 mm Pentaconn, XLR-4)
- USB key containing the user manual in PDF format and the individual frequency response curve
- Storage box
- Microfiber cloth for cleaning
Storage Box
The storage box provided with the HD820 is not just an accessory. It is designed to effectively protect the headphones when not in use, thus preserving their integrity and performance over the long term.
Main Advantages of the Sennheiser HD820
- Exceptional sound quality for closed-back headphones, rivaling the best open-back models
- Innovative glass reflector technology for unprecedented sound transparency
- Excellent sound isolation allowing use in various environments
- Robust construction and high-quality materials ensuring durability and performance
- Wide range of connection options for maximum compatibility with audiophile equipment
- Unique design combining aesthetics and functionality
- Optimized comfort for long listening sessions thanks to handcrafted microfiber ear pads
- Extended frequency response capturing the entire audible spectrum and beyond
- Complete accessories including a storage box and multiple cables
- German manufacturing synonymous with precision and reliability
