The Sennheiser HD 620S headphones offer exceptional ergonomics, comfort, and dynamic, realistic sound with deep bass, making them a solid choice for those seeking a closed-back design. However, they don’t fully match the clarity and openness of Sennheiser’s open-back models and lack a balanced connection option. Despite these flaws, they provide a unique listening experience within the Sennheiser lineup, catering well to those needing sound isolation.
Sennheiser HD 620S
The Sennheiser HD 620S headphones deliver a comfortable listening experience with solid noise isolation and durable construction. Designed for extended use, they feature ergonomic ear cups and reinforced materials. The sound is dynamic, with strong bass and clear midrange, though it lacks the openness of Sennheiser's open-back models and some of the brand's signature warmth. While they don’t offer the detail and soundstage of higher-end models and lack a balanced connection, their comfort, isolation, and bass response make them a good option for closed-back headphones.
What we like
- Excellent Comfort
- Solid Noise Isolation
- Strong Bass Response
- Durable Build
What could be better
- Lacks Openness
- Sacrificed Tonal Warmth
- No Balanced Connection
- Average Design
Intro
If you follow the head-fi market and headphones are a part of your audio-video system, you’re probably aware that Sennheiser belongs to a group of manufacturers primarily focused on open-back audiophile headphones. However, from time to time, this well-known German company surprises us by launching closed-back headphones, which offer slightly different qualities and certainly have their audience.
Construction & Design
Although the label might suggest that the new HD 620S headphones belong to the 600 series, after a brief inspection, it became clear to me that they borrowed their design from the lower 500 series. I noticed this in the hinges that connect the headband to the resonators, which aren’t directly connected but instead are attached via a curved arm that visually blends into the resonator—just like in the 500 series.
When I compared them directly with the HD 560S model, it became evident that the resonators are identical in their oval shape and dimensions, meaning they’re slightly smaller than those of the 600 series. I can say that the resonators and hinge mounts seem to be directly taken from the HD 560S but with closed covers instead of the metal mesh-covered openings. After consulting the accompanying materials, my observations were confirmed, as the manufacturer doesn’t hide that the HD 620S combines features from both of these series. However, I soon noticed some differences, as the HD 620S, unlike the entirely plastic 500 series, comes with stainless steel sliders and chrome-plated surfaces, which I’m sure will provide greater durability.
The upper headband is also made of sturdy plastic on the top, but the two-part cushion on the underside is covered with artificial leather and filled with soft polyurethane foam.
When I looked closer at the resonators, I found that the outer covers are also reinforced with stainless steel, while the inside features polyurethane cushions covered with the same quality artificial leather as on the headband, which clearly sets them apart from the 500 series.
The speaker units are protected by a plastic mesh and a fine, acoustically transparent fabric, and the drivers have an overall diameter of 42 millimeters. The diaphragm itself is 38 millimeters in diameter and is equipped with an aluminum coil, which has low mass and easy mobility. As expected, Sennheiser’s patented E.A.R. (Ergonomic Acoustic Refinement) technology is applied here, meaning the speaker units are positioned at a precisely calculated angle so that sound waves reach the ear shells slightly from the front, simulating a hi-fi system.
In terms of technical specifications, the HD 620S offers a frequency range of 6 hertz to 30 kilohertz, and the manufacturer highlights that the most significant difference in response compared to the HD 600 is in the lower part of the spectrum, where these closed-back headphones provide significantly higher loudness and sound pressure. In other words, they deliver stronger and more impactful bass. With an impedance of 150 ohms, the HD 620S falls into the category of moderately demanding headphones, which should work well with portable battery-powered headphone amplifiers and lower-powered headphone amps.
Sound Test
Given that I’ve been a satisfied owner of the more affordable HD 560S model for several years, I was eager to see how the HD 620S would compare. As I began using them, I quickly realized that the HD 620S delivers the same exceptional ergonomic qualities. They offer a high level of comfort, with cushions that completely cover the ears. I did notice they exert slightly more pressure on my head—something I assume is necessary for better isolation from the surrounding environment. The isolation these headphones provide is excellent, allowing me to enjoy great sound even in noisier environments, without worrying about disturbing anyone nearby. While I couldn’t find specific data on the weight of the headphones, my subjective impression is that they feel slightly heavier due to the metal components, yet they’re still light enough to be considered among lightweight models. As expected, the resonators can be adjusted on all three axes, and the metal sliders have clearly marked increments, making it easy to get the perfect fit.
When I began critical listening, I used iFi’s latest portable DAC and headphone amp, the hip-dac 3. Just like Sennheiser, iFi is known for its balanced and relatively neutral sound, and the combination of the two resulted in a solid analytical experience.
iFi hip-dac3 - Portable Hi-Res DAC/Headphone Amp - True Balanced…
- Enhanced Design and Functionality - The hip-dac 3, now available in a Titanium Shadow hue…
- Advanced Connectivity and User-friendly Controls - Equipped with two USB-C ports for simpl…
- Optimized Audio Performance - A true balanced circuit design, the hip-dac 3 guarantees opt…
From the first tracks, the HD 620S lived up to their promise of delivering impressive low tones, with strong and firm bass. The bass volume was prominent, but what impressed me even more was the fantastic depth, all while maintaining complete precision. I believe that few Sennheiser headphones can compete with the HD 620S in this regard. Despite this, Sennheiser has managed to achieve this without placing the HD 620S in the bass-heavy category—they remain excellently balanced when considering the overall sound reproduction. Although they provide a solid sense of space, I did notice that they don’t quite reach the openness of the brand’s open-back models—something I somewhat expected, given the physical constraints. The ultimate definition is a bit lower than what you’d find in other models in the 600 series, particularly noticeable in the extremes. However, the HD 620S fully capitalizes on its strengths, delivering convincing and almost juicy notes across the entire spectrum. The focus is exceptional, as is the macro-dynamics, with a firm bass foundation that adds a special charm to every track.
Sennheiser HD 620S - Audiophile Closed-Back Wired Headphones - Premium…
- Distraction OFF, sound ON: Open, expansive listening with noise isolation that immerses yo…
- A panoramic soundstage: Angled, 42mm dynamic transducers with 38mm diaphragms mimic a spea…
- Superior sonic precision: Ultra-low distortion at all frequencies, lifelike vocals and cle…
For the second part of my test, I paired the HD 620S with the Musical Fidelity M6x DAC, which is an excellent DAC with a fairly capable headphone amplifier. It’s worth noting that, like the HD 620S, the M6x lacks a balanced connection option—a drawback in my opinion, but it does reinforce the similarities between the HD 620S and the 500 series.
With a higher-quality source, the HD 620S delivered even more detail and better definition, bringing them closer to what I expect from Sennheiser. Additionally, since I tested a brand-new pair of headphones, the break-in period clearly had a positive effect on the sound quality, making the overall reproduction more cohesive. There was more air around the tones, especially in the upper and midrange, which also improved the soundstage. On the other hand, the low tones retained all their described qualities, and if anything, their definition became almost perfect, maintaining both mass and powerful impact.
Overall, with the Musical Fidelity, I found the sound to be slightly drier and more precise, with very clear individual tones and outstanding analytical capabilities. This experience demonstrated that the HD 620S are more than capable of accurately reproducing the technical characteristics of any recorded sound.
Album(s) used for sound test:
Lady Soul
Sennheiser HD 620S Video Review
Sennheiser HD 620S Specifications
- Type: Closed-back, over-ear headphones
- Driver Type: Dynamic
- Driver Diameter: 38 mm diaphragm with 42 mm overall driver diameter
- Frequency Response: 6 Hz – 30 kHz
- Impedance: 150 Ω
- Sensitivity: Not specified by manufacturer (estimated based on similar models)
- Total Harmonic Distortion (THD): Less than 0.1%
- Sound Pressure Level (SPL): Not specified by manufacturer (typically around 103 dB for similar models)
- E.A.R. (Ergonomic Acoustic Refinement) Technology: Drivers are angled to simulate the hi-fi system soundstage.
- Connectivity: 3.5 mm stereo jack with 6.3 mm adapter
- Cable Length: 3 meters (detachable, single-sided)
- Weight: Not specified by manufacturer (estimated to be slightly heavier than HD 560S due to metal components)
- Build Materials:
– Headband: Sturdy plastic with artificial leather-covered cushion
– Ear Cups: Reinforced with stainless steel, polyurethane cushions with artificial leather covering
– Sliders: Stainless steel with chrome-plated surfaces - Accessories Included:
– 6.3 mm stereo plug adapter
– Carrying pouch (if provided with packaging) - Compatibility: Suitable for use with portable devices, headphone amplifiers, and home audio systems
- Colors: Predominantly black with chrome accents
- Warranty: Typically 2 years (varies by region)
- Price: Approximately $350 (may vary by region and retailer)
You can download & view the manual here->Sennheiser HD620S Manual
Final Verdict
The latest addition to Sennheiser’s 600 series offers me exceptional ergonomics and decent ventilation—though not quite at the level of open-back headphones, which is understandable. The key point is that the HD 620S keeps ear cups heating below the discomfort threshold, allowing me to use them comfortably for uninterrupted intervals of two to three hours. There is a certain compromise in the sound, as these headphones sacrifice some of Sennheiser’s recognizable tonal signature to provide isolation from the environment.
However, they make up for this with strengths like powerful bass and excellent dynamics. In the end, I can say that the HD 620S are simply different from what I’m used to expecting from this well-known German brand, but it’s precisely this difference that makes them unique.
