Sennheiser HD 620S

My Mandopop Headphone
I will preface this writeup by saying this will not be the most technical review, if you can even call it that. Instead it will just be the experience of one person, experiencing a new headphone with bias.

This bias is impossible to hide, with the HD620S sharing the same store shelve as the HD600. For as much as possible, I will avoid comparing to the HD600.

I won't leave the important bits to the end, and will come out and say it. The HD620S is an easy win in my book, as a ballad centric headphone, piano loving headphone and has a characteristic emotional presentation. Pianos, guitars and instruments are it's strong suit.

Listening gear: ifi Zen Dac v1 and VE Megatron. Tracks are all 320kbps.
For easy sharing sake, I have used Youtube links below, but I recommend a lossless service of your choice, to match what you hear with what I'm hearing.

Occasional EQ used. Mostly stock tuning for testing.

茄子蛋EggPlantEgg - 浪子回頭 Back Here Again​

This is a Cantonese song with a powerful, unique male vocalist, drums, cymbals and electric guitar.

Adam Levine - Lost Stars (from Begin Again)​

This is a pretty popular song, with Maroon 5's lead singer Adam Levine, performing on a guiar in front of a crowd in a concert hall. The presentation here is likely different from anyone familiar with HD600. The sound signature that HD620S is going for here is definitely a little "hot". More treble, but not at my limit to call it sibilant. Voices are definitely sharper than normal, but not yet piercing. The guitar is pulled into focus here, which surprisingly, is not a presentation that I hate. Also, the guitar is frighteningly accurate, even if the vocals are not, in this song.

All in all, I don't think this song is rendered in the most accurate manner. Do I have a problem with that? No. I own many headphones. I have others that can do that. I am not a full fan of the presentation that the HD620S is going for with this song, but hearing additional details in guitar and a "hot" presentation, has it's place. I enjoyed this song. Less than my MDR-Z7, but I still enjoyed it.

W0LF(S) 五堅情【你是我這輩子最想愛的呀 Last Love】Official MV​

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For me, this song was made for the HD620S. This is an emotional song, with multiple different vocalists, harmonization's, drums and pianos. I am happy to say the HD620S makes you feel every kick drum and harmony powerfully. This genre plays directly into the HD620S wheelhouse, which is to let higher pitched voices shine and breathe. The song doesn't feel boxed in the way other songs might on this headphone. It is intimate yes, but not claustrophobic. At higher volumes, for more critical listening, the higher pitched singers sound absolutely beautiful.

This is a perfect song, and I am thankful the HD620S was able to make me revisit many mixed emotions about the song. The HD620S stops being a piece of gear for music like this, and starts helping you paint a picture in your mind. Just for being able to do that, the headphone is worth every last penny I paid for it and more.

Lady Gaga - Always Remember Us This Way​

Not to leave out my non-Mandarin speakers, this equally powerful song, has Lady Gaga's vocals paired with a variety of different drum types and guitars. The HD620S again, delivers a flawless reproduction of the piano and drums. Again, perfection.

陳奕迅 Eason Chan 《我們》Us [Official MV]​

This is yet another emotional song, that relies on violins, a single male vocalist and piano. When I say the HD620S performs best on Mandarin music, it means it is given free room to render the piano fully and without smearing into other frequencies. You never have to go out of your way to critically listen to pick it out. It is always there for you to pick out, and then there to marvel at during solos. But it wouldn't be perfectly good at Mandarin music if that is all it does. The little magic that HD620S does is in the little "spicy" sound signature. The moment the male vocals get higher, you hear it presented lightly, atop the blanket that of piano and other instruments. This is a cohesive presentation across all the frequencies that I need for this genre, yet a nimble enough reproduction that I am able to focus on vocals or piano depending on my listening fancy. It is technical but also, crucially, highly highly musical.

Our Times《我的少女时代》电影主題曲 -《小幸运》MV by 田馥甄​

The flipside of female led Mando-pop is also a homerun in my books. Female vocals are vastly different from male ones. And if you muck up the balance of a headphone, female vocals become shrill and piercing. This is already a "hot" headphone in the treble region, but I am happy to report that the balancing act between a "hot" headphone and female vocals is done masterfully again. I do not find the female vocals shrill. There is some treble focus on this headphone, but I do not find that to be a weakness on female vocals, or at least in this scenario. There is an angelic quality to the female voice, along with the aforementioned detail that the HD620S has a field day with, in letting the listener pick out easily.

茄子蛋EggPlantEgg - 閣愛妳一擺 Love You One More Time (Official Music Video)​

This is yet another EggPlantEgg song, heavy on the instrumentals and male lead vocalist. The focus here on the electric guitar solo in particular, showcase this headphone's technical ability. No distortion, no smearing, just a tasteful balance between drums and guitars. There is coloration, more towards the higher frequencies, but to my ear, the lower parts of the register such as guitars and drums remain untouched. This gives the headphone a skew that favors higher pitched cymbals and vocals. The end result is detail whenever a singer pushes the envelope into higher pitches, which incidentally is where all the emotion is, in Mandopop. When you belt your heart out, it is as though the HD620S is handing the singer the mic to take center stage.

Concluding Thoughts
I was initially harsh on this headphone. And I will maintain that it can be a bit inconsistent across genres. Let's get the bad out of the way. This headphone did not do Hotel California well at all, for me. It is not very good for rap music and can sound far too sharp with high hats, at least to me. It has some "spicyness" that manifests in songs that rely on high hats or other very high pitched sounds. That limits this headphone as a perfect all-rounder.

Then again, what's the point in another all-rounder. There are a ton of those, many from Sennheiser's own stable like the HD600 and HD650. I am a listener that doesn't care too much about having "one" perfect sound. I rather trust a headphone maker to come up with their own colorations, that can work magic with some genres or uses. The fun in individual headphones, is that they can please individual listeners, not a one-size fits all.

"spicy" treble presentations on some rap tracks with high hats.
not the perfect all-rounder as it is a colored (albeit lightly) listen
has some inconsistencies when moving from genre to genre. Closed-backs have yet to reach the accuracy and natural qualities that open-backs have.

this is truly a delightful listener for any ballad or Mandopop song. Artists like Li Ronghao, EggPlantEgg, Eason Chan and Hebe Tian move from powerful singers to angelic hosts on this headphone.
emotional, powerful presentation that is detailed and afford for separation across instruments and vocals. Good for incisive, critical listening.
while technically proficient, does not sacrifice musicality for that technical prowess.
rasp, strain and breaths on vocalists are clearer in the mix likely due to treble "spicyness". This "spicyness" enters the realm of elevating vocals and giving them the spotlight, but stops short of sibilant territory.

Understandably, different people have different tolerances for what is considered sibilant. But in my own listening, I did not hear or feel pain from that sharpness, nor felt that s sounds were rendered inaccurately. I think this is treble that is done both tastefully and even artistically, to make it a unique headphone.

Do I think it is a HD600 enhancement? Probably not. Have I reached for it often on my desk, despite having the HD600 and MDR-Z7? Yes. When it is time to sing or enjoy an album in all it's glory, I'm going to give the HD620S first dibs, before letting the vocal powerhouse that is the HD600 give it a go. I am extremely excited to say that the HD600 does not win all of those head-to-heads. This really is a unique headphone that I urge you to try if you like the same music that I do. It is divisive over on the discussion page for the product, but don't let graphs and opinions prevent you from enjoying something you enjoy.

The HD620S stays on the desk.

The audiophile community was on edge when Sennheiser announced that it’s looking for a partner for its consumer audio division. The name “Sennheiser” is almost sacred amongst audiophiles. It’s the company that made the world’s first open-back headphone, the HD 414—the bestselling headphones of all time—the legendary HD 600 and HD 650, and I think many of us will agree that the concept of a flagship headphone was introduced to the masses with the HD 800. Sennheiser also created the legendary HE-60 and the $60000 HE-1, neither of which require any further explanation. The community’s panic was fully justified, as that decades-long greatness was at stake. Just 3 months after that initial announcement, in May 2021, it was revealed that Sonova, “a hearing aid company”, acquired Sennheiser’s consumer audio division. This only caused an even greater panic, in fact, so much so that many fans were bracing themselves to bid farewell to Sennheiser’s legacy.

A decent amount of time has passed since then, and I think we can all agree that Sennheiser didn’t disappear, nor did any of its most loved headphone models. In fact, its over-ear lineup has grown, with the addition of the HD 660S2 and the HD 620S. Today, we are taking a look at the latter.

Disclaimer: HD 620S has been provided to me free of charge. I am not affiliated with Sennheiser, nor have I received any form of monetary compensation to publish this review. All opinions, beliefs, and findings are my own and are freely expressed as such. No company, person, or higher body overlooked or altered any contents in this article. This review is free of affiliate links.
All photography is my own. If you wish, you may view it in full resolution at: https://ibb.co/album/SDTrt2

Design​

If the silhouette of the HD 620S looks familiar, it’s because it’s the same one seen in the HD 5𝑥𝑥 series. But wait, isn’t this a headphone from the HD 6𝑥𝑥 series? It indeed is, but Sennheiser decided to make a design crossover between the two series. It was very interesting to learn that silhouette and design of the HD 5𝑥𝑥 series dates back to 2004! The initial lineup consisted of the entry-level HD 515, the mid-range HD 555, and the high-end HD 595 which was introduced the following year. I always found this design to be futuristic and appealing, but I never knew it was that old. Looking back, it was certainly ahead of its time.

The HD 620S features a fixed headband, and while it is quite plain, it plays an important role in shaping the headphones. The warmth and softness in the design language stem from the rounded-off corners and the thickness of the headband itself, and this is further emphasized by the subtle curvature at the rear end. We can see how the headband gradually extends outward at the rear, reaching its farthest point at the very top, where the it’s the widest. Branding is also kept to a minimum, with there only being a single company wordmark and two Sennheiser.

The 5𝑥𝑥 series’ trademark, however, was always the headphone yoke. The entire design is centered around this single element. Continuing the flow of that headband curvature, the yoke seeps into the ear-cups and unites the two elements into one. By departing from the traditional fork yoke design, Sennheiser was able to create an authentic yoke that connects to a single point at the rear of the ear-cups. Ear-cups have a shaved section that perfectly matches the curvature of the yoke, thus allow the yoke to rest within it. Small rubber pads between these two parts prevent wear. The shape of the ear-cups can be described as an oval shape akin to that of a musical note head. This resemblance becomes more apparent when looking at the entirety of the headphone’s silhouette.

The ear-cups can be divided into two sections: outer shell and the driver chamber. The driver chamber is seated within the outer shell. It’s the only part that embodies the Sennheiser logo, and it honors it in a sleek way. It’s as if the plastic were a cloth that was pulled over the raised logo section.

The design of the HD 620S is mature and elegant. I will continue being a fan of it as long as it doesn’t deviate too far from the original. It’s almost as if the design derives from the automotive industry. In fact, it reminds me of the McLaren P1. It’s sleek, stealthy, and sexy.

Build Quality​

I think many of us were disappointed with the quality of the HD 6XX, and left questioning whether Sennheiser had “sold out” and gone into the commercial direction. As of today, I can say that although Sennheiser has taken the more commercial route, it has done so without compromising the quality of its products. The HD 620S is a prime example of this. Yes, it is fully made of plastic, but it’s still unmistakably a Sennheiser headphone. I haven’t shied away from praising the HD 598 to the heavens. After 8 years of use, other than the pads, it has no signs of wear. I adore that headphone. In my eyes, it set a benchmark for what high-quality plastic should look and feel like.

The HD 620S implements 4 different plastics. The headband features cheaper plastic, while the yoke uses very smooth, premium plastic. It’s so smooth that it feels rubberized! The outer shell of the ear-cups also uses a premium type of plastic, but not the same kind as the yoke. The most intriguing part is the driver chamber, which uses a top-tier plastic—the same kind you’d find in professional cameras. The only other headphones I know of that use this kind of plastic are from Japanese brand Crosszone.

Overall, the HD 620S met my expectations for build quality. There’s no creaking, and they feel tough and durable. I don’t doubt for a second that they can withstand a lot of wear and tear.

Comfort​

With a weight of 326 grams, it’s neither the lightest nor the heaviest headphone. But being in the low 300s, it’s fairly light and below average. Sennheiser has always excelled in the comfort department, and the HD 620S is no exception. The ear-cups offer enough horizontal movement to adapt to the shape of my head, and there’s a good amount of tilt as well. The protein leather ear-pads and head cushion are soft and remain comfortable even during extended listening sessions. I experienced no hotspots or sweaty ears, so no complaints in that regard. The oval ear-pads, which worked for me on the HD 598, have also been improved here—the issue of my ears touching the raised part inside has been resolved. Something that I enjoy in general is high clamp force, especially when it concerns closed-back headphones. Thankfully, the HD 620S has higher clamp force than the HD 598, allowing the headphones to stay in place while maintaining a tight seal around the ears.

If you’ve tried previous models with this silhouette and found them comfortable, the HD 620S will likely fit you just as well. The only notable difference is the slightly increased clamp force.

Having logged countless hours with the HD 598, I can confidently say that it’s high up there in terms of comfort. I now use the HD 620S on a daily basis, as they offer what I consider to be an ideal level of comfort.

Cable​

The included cable is pretty basic. It’s 1.8 meters long, 2.5mm TRRS connectors on the headphone end and 3.5mm TRS connectors on the source end. While the rubber quality doesn’t quite match the level of the HD 598’s cable, it’s still good—flexible, tangle-resistant, and pleasant to the touch. I’ve always been a fan of the twist-lock mechanism because it prevents the cable from getting yanked out. The cable has a bulky (in a good way!) 3.5mm housing with a thick strain relief for added durability. The rubberized material of the housing makes it very grippy and easy to handle. Altogether, it’s a good cable.

One welcome addition from Sennheiser is the availability of an official balanced cable, a 4.4mm TRRRS cable that you can purchase.

Isolation​

They offer solid passive isolation for a closed-back headphone. Everyday noises such as a laptop fan, passing cars on the street, or even the hum of a loud vacuum cleaner, all get effectively masked out. While noise isolation is nowhere near the noise-canceling levels of ANC-equipped headphones, their isolation is more than sufficient for creating a focused listening environment at home or in quieter settings.

For all individuals with hair on their head, make sure to scoop it out of the way all around the ear-pads, allowing them to sit flush against your skin. This step is crucial for achieving a vacuum-seal, which not only enhances isolation but also ensures optimal sound quality. Small adjustments like this can make heaps difference in the listening experience.

Sound Performance​

Sennheiser has never been about delivering overly flashy sound profiles. Instead, they focus on precise tuning, creating headphones that perform exactly as intended. Some of their tunings have been universally praised, while others have sparked more polarized opinions. If you’re looking for a colored and exaggerated sound profile, you’re going to have a hard time finding a match from Sennheiser’s portfolio. But for those in search of a more neutral and refined sound, Sennheiser offers plenty of choices. The HD 620S prioritizes balance over boldness. Above all, the HD 620S delivers a pleasant and engaging listening experience.

Setup: foobar2000>FiiO KB3>Sennheiser HD 620S

Lows​

Starting off with what appears to be the determining factor for headphones these days—the bass. The HD 620S delivers. Quality is prioritized over quantity, which is not to say it is lacking the latter, quite the opposite, actually. Before expanding on that, I would like to point out that this is a mid-bass dominant headphone, which is somewhat atypical for a closed-back headphone. The significance of this choice shouldn’t be underestimated, as that’s what shapes the overall sound character of the HD 620S. The mid-bass is gently elevated, having a solid amount of presence without being disruptive. A close relationship is established between the quantity and the quality, creating a bass response that is both impactful and technically defined. The technical performance here is remarkable, offering a tight slam, hard impact, all while retaining a tactile transient response. What caught me off-guard, however, was hearing the texture in the bass. It extends to the physical dimension, where you are able to feel the nuance in sound—a layer that is usually uncovered in a rare handful of TOTL models.

The sub-bass takes is more reserved in comparison, presenting a delicate but defined rumble that adds fullness without overwhelming the mix. It supports the mix rather than dominating it. Those expecting an intense, club-like sub-bass might find it more restrained than anticipated, but the overall presentation is one of subtlety, offering just enough presence to reveal itself where needed. If it were cranked up any further, I feel like the fine balance would be disrupted and it would perhaps add an unwanted weight to the sound. Several problems could arise from this, one of them being the degradation of sound quality, but also how long you can listen to them without experiencing fatigue.

The low end is certainly impressive and it allows for other parts of the frequency spectrum to shine.

Mids​

Unsurprisingly, the mid-range is the highlight of the sound signature. After all, the legacy of the “6” series has been long established on neutral and accurate mid range. If you’re someone who appreciates reference-grade headphones, the HD 620S’ mids will appeal to you.

The HD 620S truly shines in its reproduction of acoustic instruments, particularly the acoustic guitar, which stood out in quality. It captures the authentic resonance and texture of metal strings, whether they’re strummed or plucked. This level of detail in the mid-range is uncommon in this price bracket, adding depth that pulls you directly into the music. I actually found myself listening to acoustic music far more than usual, which should carry over just how much I enjoyed the listening experience. I’ve spent close to a dozen hours just listening to classical music with these headphones. Perhaps this sounds like a light number to some of you, but for someone who might normally listen to only 20 minutes of classical, if that, it was very much out of the ordinary.

Vocals, on the other hand, are more in-line with the expectations. Male and female vocals are comparably neutral, though I noticed a slight hint of forwardness coming through some female vocals, which adds a nice touch of intimacy without veering into sibilance or harshness. Given that our ears are particularly sensitive to mid-range frequencies, where any tonal imbalance is immediately detected, I’m happy to report that the HD 620S presents an impressively even response across this range.

I did not expect to enjoy the sound of both electronic and acoustic instruments this much! Vocals? It’s Sennheiser, I knew I’d be in good hands. But the way it handles instruments has been a surprisingly delightful discovery.

Highs​

Of the three frequency ranges, this one put the biggest smile on my face. I have a personal love for treble, and the top-end performance often dictates whether a headphone makes it into my private rotation. While I can appreciate various tuning approaches, a well-executed treble response is almost a guaranteed ticket to becoming one of my go-tos. The HD 620S, with its crisp, snappy, and energetic treble, ticks all the right boxes. It has a lively top end that keeps the sound engaging. Percussion pops, vocals that reach into this range have grit and texture, and sparkle is present in instruments of all kinds.

Above, I undersold the transient response speed as simply “snappy.” In truth, the HD 620S is lightning fast, so much so that I would go as far as calling it exceptional in that regard. It can keep up with demanding genres whilst still retaining the definition of the treble.

With its neutral tuning, however, it’s worth noting that the HD 620S can be somewhat unforgiving on poorly recorded tracks. These highs won’t shy away from revealing rough edges—not sharp enough to sound fatiguing or bothersome, so don’t be deterred! But for listeners accustomed to smoother mids that mask imperfections, this edge might be something to note.

Soundstage & Imaging​

As many have noted, openness and soundstage size are standout characteristics of the HD 620S. You hear it right off the bat, and it’s interesting, because the HD 620S is a closed-back headphone. It’s nothing groundbreaking for closed-backs to sound like this, but they do tend to be in a higher price bracket. Here, I found the soundstage to be impressive width-wise, extending beyond the ear-cups, while I found it to be average in depth. This can be attributed to the angled driver placement, which shifts the entire presentation forward. Another design factor that impacts the acoustics is the absence of vents in the ear-cups. We are especially reminded of its closed-back nature, as sound isn’t as airy as on open-backs… It doesn’t take a genius to make that observation. However, this is not to say that the sound is heavy, weighty, or congested—to my ears, it’s fairly light, actually.

On another note, the entirety of the soundstage is well-utilized thanks to the accurate imaging. Each element occupies a distinct position within the sound plane, which makes for a quite exciting listening experience when putting on intense segments like rolling drum passes. You’ll be in for quite a ride!

Conclusion​

I can safely say that the HD 620S is the proof that Sennheiser is here to stay. It’s in good hands. The company successfully expanded the HD6𝑥𝑥 lineup, and this latest addition is one worthy of its spot. This headphone not only won my heart, but also made it to my personal rotation of headphones. I found it to be a superb choice for watching movies, playing video games, and above all, listening to my favorite tunes! It’s pleasant to the ear, it has a nice light sound, it’s well-built, it’s comfortable, replaceability is not a concern, the cable isn’t bothersome—it meets the criteria for a good headphone. When I have it on my head, it feels like I have a private theater all to myself.

Despite my rich collection of headphones, which, mind you, consists of some very fine and exceptional models—headphones that redefine the listening experience—I still found myself reaching for the HD 620S the most frequently. Its versatility allows it to fulfill my casual needs, and perhaps that’s what makes it such a great overall choice. It’s not overly flashy in any aspect and doesn’t seduce you at first glance, yet no matter what you throw at it, it performs well. I felt like my pair opened up after 150 hours, so I suggest you give your pair some time to break in.

My audiophile journey started with the HD 598, and it was also the first headphone I ever reviewed (my first review on Head-Fi!). For me, it’s a full circle moment to reunite with Sennheiser.

The HD 620S can be found for $100 off on some websites, and if I’m being asked, at that discounted price, it’s a no-brainer. If you are in the US, Sennheiser has it officially listed for $250. In my eyes it’s worth the sticker price, but if you’re having a hard time pulling the trigger and there are no deals for it in your area, it’s worth asking your local dealer for a generous discount, or you can at least try finding one online. The HD 620S hasn’t left my head since I received it, making it my new daily driver for the past 4 months. I hope that answers the question whether I recommend it or not

You have two thumbs up from me, Sennheiser. Well done!

As an recording engineer who does a lot of location recordings, I have been looking for a pair of good closed-back headphones for a while. Everyone else in the industry use Beyerdynamic DT770s, which I have and like, but they are not quite good enough compared the open back cans I use at home (mostly Hifimans). I certainly would not mix with the DT770s, although I know some engineers do. For a while, I tried using open-back Hifiman cans on-location. They work, as in, they provide enough spatial clues for me to place microphones correctly. The obvious draw-back is that the sound leaks both ways, and sometimes I would not hear the little details that could ruin a recording (such as the humming from a cable, or an orchestra conductor.) Therefore, I have been looking for a pair of good, closed-back headphones for about two years now. There were some obvious options (like Audeze LCD-XC) but I wasn't sure I wanted to shell out $1600 or more for something I only use on-location.

This June, when the HD620s came out, I was very curious. I had one other contender I wanted to try out- Audeze Maxwell. I have only read good things about it, but wasn't sure it was going to be the right pair for me, since everything passes through some sort of DSP, even analog signals. Therefore, I went to a shop to listen to them before I pulled the trigger.

I heard 4 pairs at the shop, switching back and forth. My source was my Sonosax SX-62R portable recorder, the device I use on-location, therefore it would make sense that I use this machine as the source. The four pairs were- Audeze LCD-XC, Audeze Maxwell, Beyerdynamic DT1770, and Sennheiser HD620s.

Very quickly, I ruled out the Beyer and the Maxwell. Beyer was uncomfortable to me, and didn't sound that different from DT770. Audeze Maxwell sounded good, but I think the DSP changed imaging too much for me to trust them. It was then between the LCD-XC and HD620s. After half an hour, I decided on the HD620s. Sonically, the LCD-XC had a slight edge, there were more spatial cues in the sound. HD620s were not far behind sonically, had very good isolation, didn't weight two tons, was easy to get a good fit, and cost about 1/5 as much as the Audeze. In the end, I bought the HD620s and went immediately to a recording session.

How do they sound?

Very, very normal. I don't detect any significant peaks or dips anywhere. No funny reflections from the housing, which ruin many otherwise high-end closed-back headphones. Good job to Sennheiser here. They sound more detailed than headphones like HD600 or HD650 (both are very good, I know, but they sound somewhat lo-fi to me in this decade). Soundstage is okay. It's not nearly as big/expansive like open back headphones, but it would be silly to expect that in a pair of closed-back cans. Initially, I expected to only use them for location recordings. However, I find myself using them much more than just that- movie nights at home, airplace travel, and on-the-go critical listening. They sound decent out of all devices I throw at them- Questyle M15, Hifiman Serenade, Prism Sound Orpheus, Apogee Boom, and even my laptop headphone out. I quite like the finish on the earcups too. Very Japanese.

I have taken them across three continents on my works trips so far. There is one cloth bag included, but I haven't been using it. I have, instead, beat them around and just threw them in my backpack. No problem so far. For me, the comfort is great, although a bit hot for summer, but that's all headphones. Definitely recommended.