Sennheiser HD 550 Review: A Legitimate Gamechanger

Two releases from Sennheiser’s audiophile headphone division in as many months is pretty wild, but here we are. Allow me to introduce the Sennheiser HD 550, their newest entry to the 5 series lineup coming in at $299 USD.

With the HD 505 I recently reviewed, we saw Sennheiser take a moderate step forward with the 5 series platform with regard to ergonomics and sound quality, but now we have the HD 550, which shares the clamp improvement of the HD 505, but with a slightly different approach to acoustics.

The questions on everyone’s mind are probably what typically follows a Sennheiser release: “How does it compare to the HD 6x0 series? Is it a better value than the HD 6XX?” but with a few more added on, like “What is the deal with this new naming scheme?” and “How different is the HD 550 compared to the still brand-new HD 505?”

Honestly, my question is this: Sennheiser has indicated that new headphones named “HD x50” should be neutral… but does HD 550 actually live up to that standard? Let’s talk about it.

Build, Design, Comfort, and Accessories

I’m going to keep this brief because the comfort and accessories are literally identical to the HD 505 that I just reviewed, so if you want all of the details, feel free to check out that review. HD 550 shares the same chassis as far as I can tell, the same pads, the same headpad, the same cable, and the same bag.

Touching on visuals, to be honest I prefer the look of the HD 505. This more muted grey and black probably works better for the people who want their headphone to be minimally distracting, but it also (partially due to the swirly single yoke design) looks much more dated and austere than the HD 505. Even if it doesn’t necessarily make me want to use it less, the HD 550’s somewhat drab visual design may well have that effect on others.

All of my notes on comfort from the HD 505 review could be pasted here with no changes, though. I actually kind of like the ear comfort of this chassis now that the clamp has been reduced, but I really dislike the headband pad. No notch in the center of the headband and insufficient padding make it among the less comfortable “lightweight” headphones I’ve tried for comfort.

I will note here that I wear the HD 550 the same way that I wear the HD 505: pushed as forward and low on my head as possible, which involves the flange of my pinna tucking underneath the backside of the earpad slightly. This has been a common recommendation for as long as I’ve been in the hobby, and it’s also how I measured the headphones to best reflect the response I may have gotten when wearing them.

Credit to Meier Audio

Unfortunately though, not everyone is going to find this position comfortable or natural, and as a result other people may get a different (likely brighter) sonic result listening to HD 550 than I get. All I can do is review the headphone as it naturally sits most comfortably on my head, so apologies to those who feel this review doesn’t accurately reflect their use condition with the headphone.

The HD 550 doesn’t do anything revolutionary here—especially given the last headphone I tested was identical in more ways than one—but it’s still an overall solid package that I think a majority of people will find eminently usable in their day-to-day listening. It’s just not as comfortable as I think it should be given how lightweight it is.

Sound

This is one of the best measuring headphones that I’ve ever had the privilege to review, and because of that I want to be clear that it’s not perfect… but it’s damn solid. Not “solid for the price” or “solid compared to its competition.” Just solid.

The bass extends better than most of the Sennheiser open backs I can remember testing besides maybe HD 800S, but it’s not “sub-bassy” by any stretch. It’s adequate enough for things like modern pop or electronic music to not sound like something is terribly amiss, while not being quite at the level of planar bass for how well fundamentals are represented in the bottom octave relative to their harmonics.

Because of the rolloff there’s a minor tilt towards the first harmonics of bass guitars that is noticeable as a slight puffiness, but I actually tend to prefer this approach to bass over the alternative; sub-bass emphasized considerably over mid-bass tends to sound more incoherent and sluggish to me.

The mid-bass (40-120 Hz) is—for me, who prefers a bit less than our current preference bounds dictate—right where I like it. I don’t get any of the cloying slowness typical of large boosts in this region, but also don’t get any of the thinness that arises on headphones like the Audeze LCD-5 which have too little mid-bass compared to their upper midrange, which causes a nasally and somewhat IEM-like smallness of presentation.

Those who like decisively bass-boosted headphones will not find their ideal presentation here, but I think those who already find the HD 650 or Hifiman Sundara present enough in this band will find the HD 550 on equal footing with regards to mid-bass presence.

The upper bass between 120-240 Hz is where this headphone really starts to impress me, though. Mostly because it’s an incredibly hard area to balance when you have to deal with bass rolloff. Too much emphasis in this area and the bass deficit will be more noticeable and the midrange balance will likely tilt too much towards warmth. Too little in this area and the headphone will sound thin, weightless, and potentially even harsh.

But the HD 550 accomplishes a balancing act few headphones I’ve ever heard have pulled off, having just enough warmth to lend intimacy and fullness to vocals, weight and density to snare drums, and woody resonance to electric guitars and pianos, all without contributing an ounce of occlusion or murkiness to the midrange.

Speaking of which… I’m going to have to actively try and stop myself from gushing hyperbolically in this review, but I can’t think of a headphone in recent memory that I’ve enjoyed this much when it comes to its midrange presentation. It somehow improves on even the HD 600 for my preference, having a bit less warmth in the lower-midrange than HD 600, while also having less upper-midrange to balance out the aforementioned reduction.

This is exactly how I wish the HD 660S series headphones were tuned in the midrange: different, but in a way that strikes essentially the same overall balance and still sounds just as natural. HD 550’s midrange is still—like HD 600—strictly-adherent to the anatomical baseline we know humans expect to affect incoming sound, but I think HD 550 is actually less likely to be heard as “shouty” compared to HD 600.

I could throw out a ton of audiophile buzzwords to describe the midrange’s effect on music, but the problem is it just sounded correct on literally everything I listened to… which doesn’t lend itself to interesting language. Voices, guitars, pianos, horns, bowed strings, synthesizers, all just sounded normal with no asterisks, disclaimers, or qualifiers. This is not common, but it is very welcome.

Moving upward from the midrange, this is where things get a bit more complicated. While listeners thankfully won’t find the same 4 kHz glare from the HD 560S, they will find a similar set of compromises in the HD 550 that were present in the HD 505 I recently reviewed. There’s a noticeable scratchiness due to a 5-6 kHz elevation on my head, which causes certain vocalists to sound like they’re singing through gritted teeth. For those who have typically found 5 series headphones to have a “dry” character to them, the HD 550 doesn’t quite buck that trend.

However, like the HD 505, HD 550’s treble works exceptionally well for me above the 6 kHz point. On my head most headphones have a large dip in the 7-8 kHz region and a large peak in the 9-12 kHz region, but HD 550 seems to curtail both of these issues on my head, filling in the 7-8 kHz region slightly while meaningfully reducing the shriek I often get above that.

As a result, bouts of upper-treble sibilance are exceedingly few and far between, even on records that I know have issues in this region. Unfortunately though, the grittiness from the lower treble boost still persists, defining the overall timbre of the headphone a bit more than I’d like.

I feel like because HD 550’s frequency response is so darn close to perfect for me, the one real flaw it has can stick out like a sore thumb at times. The bass strikes a nice balance of compromises, the midrange is one of the best I’ve ever heard, and most of the treble is excellent… it’s just that one presence elevation around 5-6 kHz that people should be aware might be an issue for them.

Presentation

The subjective aspect that matters most to me is timbre… if we’re counting this as a subjective aspect separate from frequency response anyway. To be clear, we really shouldn’t separate the two, but some listeners do. So I am going to touch on it here briefly because it’s where I feel HD 550 has a leg up compared to other headphones it’s likely to be compared to.

Everything with significant midrange presence is presented near-perfectly, but if something has significant lower treble presence, the HD 550 will likely color things to sound slightly sandy with a bit too much crash.

However, the perceived (see: subjective) correlation across the “frequency + time spectrum” is very good with HD 550. Treble arrives and decays first, then upper midrange, then lower midrange, then bass. Before moving forward I should mention more clearly that I’m referring to my subjective unpacking of frequency response here, not time domain measurements or CSD shenanigans.

Headphones with large bass boosts tend to have overly-long perceived bass decay, to the detriment of overall coherence; bass overshadows the other regions, especially the midrange. Other headphones with large treble elevations—or large bass deficits—tend to place too much emphasis on the first millisecond of transients, leading to the presentation sounding thinned or “ethereal”. HD 550 has neither of these issues, and sounds well put-together on basically all music.

Despite the perceived time coherence between regions of the tonality here, I would say the dynamics of HD 550 are neither great nor terrible. It keeps up very well with the changes of fast-paced music thanks to the lower-midrange not being quite as pushed as similar designs, and having a bit more in the 5-8 kHz band, but I wouldn’t say it’s traditionally “punchy” on the level of the (by comparison, overall more colored) Focal headphones.

Regarding detail, I don’t think HD 550 is going to direct the attention of listeners to new facets of their music unless they’ve been listening with very bad headphones prior, so I think it’s likely most people don’t perceive HD 550 as particularly “detail focused”.

However, for someone like me, for whom “detail” is more about minimizing masking than the exciting colorations that bring a new perspective to familiar music, HD 550 masks less than most headphones I’ve tried. In other words, it emphasizes the parts of music that should be emphasized, while not emphasizing those that shouldn’t.

Lastly, the sense of overall spaciousness is solid. Not incredible or life-changing, but less claustrophobic than some of the headphones I’m going to be comparing it to. The image placement is very fair with a natural but not exaggerated sense of separation across the x-axis. A benefit of headphones with minimally-problematic treble is that I don’t get any weird smearing of images or strange skewing of the overall stereo field like I get with brighter headphones. Everything is evenly distributed and sensibly placed, with no glaring exceptions.

Comparisons

Vs. FiiO FT1 Pro

By my estimation, the FT1 Pro hasn’t gotten enough praise for what it is. Yes, it has an excursion limit which limits the amount of bass that can be pushed at high volumes, but in terms of an overall tuning at this price range, it has meaningful upsides compared to its competition: more bass extension (and elevation) than any of the open Sennheisers or Hifiman Sundara, while having a much more sensible treble tuning than the Hifiman Edition XS or HE400se.

While still having important flaws—a scooped midrange that makes things sound soft, and a scratchy lower-treble character (similar to the HD 550, actually)—FT1 Pro represents probably the most fairly-priced planar magnetic headphone I can think of for people who want to try a headphone with that kind of presentation.

Compared to HD 550, they both share a similar treble character, but the HD 550’s is less apparent due to the upper-midrange being considerably more present. The treble above 3 kHz on FT1 Pro sounds more boosted because of the upper-midrange dip, and thus plays a bigger role in defining the timbre of the headphone. With HD 550, the treble as a whole sounds more on-level with the rest of the frequency response.

Importantly, HD 550’s midrange is exceptionally well-balanced and natural sounding, while the midrange is arguably FT1 Pro’s Achilles Heel. HD 550 sounds less soft and feathered on transient hits, more coherent in terms of its imaging (especially regarding how center-panned elements like vocals and drums are layered), and more textured on instruments like bass and piano. While the FT1 Pro is an important headphone that people should definitely be considering in this price bracket, I think the HD 550 is just more cohesive overall, sounding more correct with a wider variety of music.

Vs. Sennheiser HD 560S

Unless you really need to spend less, or really want a brighter headphone, I see little reason to entertain the HD 560S over the HD 550. The HD 550 fixes every major tonal issue I have with the HD 560S while having a more even dynamics presentation and better comfort.

Some people might find HD 560S more spacious or more detailed for one reason or another, but I personally find HD 550 better all around. It’s more spacious due to images being less close & in my face, more precise with imaging because the structure of sonic images isn’t altered by errant treble elevations, and more detailed due to the absence of masking factors that damn near ruin HD 560S for me.

Of course, your mileage may vary, but I really never liked this headphone or found it to be a particularly good value. The FT1 Pro is better for less money, and the HD 6XX is way better for less money.

Vs. Sennheiser HD 490 Pro

In my review of the HD 490 Pro, I mentioned that treble was pretty bad sounding for me, but the midrange (with the Mixing Pads at least) was viable, and represented an incremental step forward for Sennheiser’s non-6x0 series headphones. The HD 550 does away with incrementalism, goes full-send with an industry-leading midrange tuning, fixes almost all of my issues with HD 490 Pro’s treble, all while keeping the same level of bass extension at a lower price. It is a better sounding, better value headphone by any metric I can think of.

Unless one prefers the HD 490 Pro with the Producer Pads, in which case the extra bass and treble of the HD 490 Pro may very well make for a more exciting, electrifying listen. But to me, HD 490 Pro just doesn’t sound as normal as the HD 550 does, sounding softer in terms of dynamic contrast, a bit disconnected in its placement of images in the stereo field, and lacking critical transient detail on pianos and plucked strings.

The HD 490 Pro (with Producer Pads) is a much more comfortable and well put together headphone, though. So for those who care most about that and are going to be EQing, the HD 490 Pro does have at least one benefit over the HD 550.

But I’m going to say HD 550 is a better sounding headphone across the board. While HD 490 Pro sounds okay with the Mixing Pads, these pads are less deep which means ear comfort suffers considerably as a result. So if the choice is between the better sounding (but less comfortable) HD 490 Pro configuration, and the HD 550… the latter is both more comfortable, better sounding, and less expensive.

Vs. Sennheiser HD 505

HD 505 is where the competition starts to get tough. HD 505 is a solid headphone, and one of Sennheiser’s best entries to their catalog since the HD 800… but I think the HD 550 is considerably better.

The reduction between 2-5 kHz does the HD 550 a ton of favors when it comes to making the headphone more versatile across genres. It makes the bass more apparent & full sounding, and lessens—but doesn’t fully eliminate—the “thin, dry” timbral character that the HD 505 and HD 550 ultimately still share.

This one upper-midrange difference is enough to take a good headphone in the HD 505 and elevate it to a great headphone in the HD 550, such that I think if people are shopping between them, the HD 550 is going to be the no-brainer pick for a majority of people.

Especially because everything else about these two headphones—including performance in subjective aspects like dynamics, detail, and spaciousness—seems near enough to identical that it’s really just a question if you want a thinner, more intense midrange with HD 505 or a more all-rounder type of midrange with HD 550. One more detail for those who are curious: the two *are* acoustically different, as is eminently visible in the differences of the front volume—specifically the differences between the baffles of each headphone.

HD 550 on the left, HD 505 on the right

The HD 550’s baffle seems purely based on visual inspection like it may be a more restrictive / higher acoustic impedance material overall, but it also leaves more of the driver area exposed, whereas the HD 505’s baffle seems more permeable / lower acoustic impedance, while covering up a bit more of the outer circumference of the driver front.

You can’t really go too wrong with either, but I do think the HD 550 is my preference between the two since it represents a particularly well-rounded offering that is pretty hard to beat. Speaking of which…

Vs. Sennheiser HD 600 and HD 650

David, meet Goliath. The HD 6x0 comparison is typically the part of a headphone review where I say “this new headphone might be fine for a certain person, but it doesn’t come close to the well-roundedness or versatility that the HD 6x0 series headphones offer, so people should just buy HD 600 or 650 instead”

It’s more complicated this time around.

Despite the praise often lavished on them, HD 600 and 650 are not perfect headphones. They have legitimate—for some, dealbreaking—flaws that can and should be improved on. To my mind, HD 550 does improve on the HD 6x0 series in two important ways others may find reflected in their experiences (with one extra improvement I think may be specific to me). Before I go further I should also say, all comparisons from this point onward are made with fresh earpads, because the HD 6 series headphones lose a significant amount of treble as the pads wear over time.

Firstly, the HD 550 has more bass extension than HD 600 and 650, which I think is a rather unambiguous benefit. Thankfully it isn’t a trade-off like with the HD 560S where it technically had more bass extension, but was so much thinner in the upper-bass and lower-midrange that the bass quality and texture suffered dramatically. HD 550 has essentially the same tuning as HD 600 under 500 Hz, but with more bass extension under 100 Hz. Easy win.

The second benefit of HD 550 is that the midrange structure is actually a bit closer to what a typical person may find “correct”, specifically when it comes to the 2-4 kHz region. The HD 600 and 650 have a bit of what Resolve has previously called a “shifted” ear gain, where the primary resonance of the headphone actually rises a bit later than the ear naturally expects.

To me, this lateness of rise is actually heard as a more significant coloration than it may appear. I hear HD 600 and 650 as having a slight grain-exemplifying peak at 3.5 kHz, and a mild under-representation of 2 kHz bite.

The HD 550 addresses both of these things. It has more (but not too much) energy in the 2 kHz band, which helps it sound more focused and precise on plucked strings, piano, and snare drums. But it also has less intensity at 3.5 kHz, which is a region I think may be responsible for some hearing the HD 600 in particular as “shouty”.

The third benefit I want to touch on is more personal, but I find the upper treble of HD 550 considerably less fatiguing and sharp to my ear. This area is my main complaint when it comes to the HD 6x0 series headphones, but especially HD 600. Because the HD 550 has similar midrange tuning but the upper treble works better for me, I can confidently say I prefer it to HD 600.

But because we’re talking about treble, judgments of this region will be highly individual. It’s not only possible, but likely that people will find the HD 6x0 series to have a smoother treble presentation. The HD 550’s treble response above 6 kHz is darker overall—for me, at least—but this also means its lower-treble rise and dryness of timbre is more apparent.

The HD 600 and 650 have a similar (though not exactly the same) 5-6 kHz rise as HD 550, but also have an upper-treble rise around 10 kHz that actually ends up balancing it out somewhat. Because of this balance, the treble of the HD 600 and 650 sound moderately silken and “sweetened” in a way that HD 550 doesn’t.

Additionally, I think HD 600 and HD 650 are a bit more detailed due to the more forward upper treble, with HD 600 being a clear leader in this respect. That said, the HD 550’s imaging is bereft of the oft maligned “3 blob” effect the HD 6x0 series has. Now, HD 550 is not an incredibly spacious headphone or anything, it’s just a bit less helmet-like and eerily separated than HD 600 and 650.

While HD 550’s improved bass, midrange, and upper treble is enough for me to easily prefer it to the HD 600, HD 650 still has the smoothest overall presentation and is clearly the most forgiving of the bunch. So HD 650 is probably still the safest recommendation, but I prefer the HD 550’s bass and midrange presentation to either of them. For the treble I favor HD 650 slightly above HD 550 though, as the HD 650’s treble silkiness is pretty addictive when it works.

Vs. Sennheiser HD 6XX (The Value Question)

I think a good amount of people will find the HD 650 more comfortable, nicer sounding, or both when compared to the HD 550, and the fact remains that the HD 6XX is just an HD 650 but priced insanely competitively ($80-100 lower than the HD 550 most of the time).

So for those reasons, I don’t think the HD 6XX is going to be dethroned as the value king this time around. HD 550 is one of the rare “uncontroversially good” headphones in a market that increasingly looks like a sea of overpriced mediocrity, but I fear the HD 6XX is priced so aggressively in the United States that it’s unlikely we’ll see anything beat its value at full retail price any time soon.

However, it must be said, Sennheiser is a very large company that legitimately sells all over the world, and the HD 6XX is only available at the “aggressive” price in the United States. Everywhere else in the world, its price is much more comparable to that of an HD 600 because one would have to pay for shipping + customs fees.

With the release of the HD 550, a ton of people around the world are now going to have access to a great sounding, locally-cheaper-than-HD 600 option, made by one of the only headphone manufacturers known for consistently exceptional build quality, user-serviceability, and longevity.

That is a monumentally cool development for the worldwide headphone market, and its one I feel should not be undersold.

It may seem a bit banal to western readers, but I think we sometimes forget North America isn’t the entirety of the consumer base for these products. Even if it doesn’t beat out HD 6XX for value here, HD 550 coming to market genuinely represents a massive upswing in value for worldwide shoppers, and I’m truly so excited for headphone enjoyers around the world to get a chance to try these.

Conclusion

Not gonna lie, this review was pretty nerve-wracking to write.

I am hyperaware of reviewers getting hyped up and claiming a headphone is an “HD 600 KILLER!!!” either because they got swept up in the excitement, it’s a clickable title, or both. I really, really don’t want to be that guy; I’ve gone this far without resorting to a ton of hyperbole or undue fanfare, and don’t really want to change that.

But the HD 550 is an extremely rare headphone, and probably one of the most important releases for the world of headphones since I joined this community.

In case that sounds hyperbolic, let’s briefly recount what was accomplished here:

• Exceptional midrange tuning, at minimum on par with the best headphone midranges ever (but maybe even better)
• Better bass extension than HD 650 without sacrificing midrange tuning or clarity at all
• Less expensive than the retail price of HD 600 (and unlike HD 6XX, available worldwide)

Accomplishing one of the first two things is enough to make for a solid headphone.

Accomplishing all three is genuinely unprecedented.

While the HD 550 absolutely has flaws—the lower-treble may be an issue for some, and the ergonomics won’t work for everybody—the fact remains: HD 550 is one of the most sensible, normal sounding, fairly priced headphones I’ve ever had time with, and the headphone market is much better off because it exists.

If you have any questions or want to chat about this article, feel free to start a discussion below on our forum, or ping me in our Discord channel, both places where you can find me and a bunch of other headphone and IEM enthusiasts hanging out and talking about stuff like this. Thanks so much for reading. Until next time!