Grado Signature S550 Review: A New Side Of The Grado Sound

Open-back headphones occupy a rather specific place in the headphone market. They are rarely the pair you buy for commuting, working in a busy office or taking onto an airplane. Sound leaks out, outside noise gets in, and most of their advantages only become apparent when you have a quiet place to actually listen.

For people who do have that space, however, open-back headphones remain some of the most compelling options for serious listening. Removing the need to acoustically seal the earcups can create a more natural sense of space around instruments and vocals, which is why open-back designs remain so common among audiophile headphones meant for a desk, listening room or private office.

Few companies are more closely associated with that kind of headphone than Grado. The Brooklyn-based company has spent decades building open-back models around an immediately recognizable formula: circular earcups, exposed metal rods, foam cushions and, on many of its premium headphones, wooden housings. Some of those designs have become classics in their own right, giving Grado the unusual challenge of introducing something new without losing what made its existing headphones desirable in the first place.

That is where the Signature S550 becomes interesting. Rather than simply sitting above or below one of Grado's established Classic Series headphones, the S550 belongs to the newer Signature Line, a range intended to give the company room to explore a different sound while its more traditional headphones continue alongside it.

So after decades spent refining one of the most recognizable open-back headphone families in the industry, what value does the Signature Line actually add to an already well-established lineup of classic Grado headphones?

Grado Signature S550: Key Specifications

• Price: $995
• Driver: 50mm S2 dynamic driver
• Design: Open-air
• Frequency response: 6Hz–44kHz
• Nominal impedance: 38 ohms
• Sensitivity: 112dB SPL at 1mW
• Weight: 335g
• Cable: Detachable Signature Silver
• Headphone connection: 4-pin balanced mini-XLR
• Source connection: 3.5mm with 6.3mm adapter
• Cushion: Grado B Cushion

Pros

• Surprisingly powerful and clean bass for an open-back headphone
• Highly detailed sound without needing an enormous soundstage
• Energetic presentation works exceptionally well with modern music
• Natural midrange
• Beautiful modernization of the traditional Grado design
• Detachable cable system
• Comfortable for long sessions once properly adjusted
• Interchangeable cushions provide another way to tune the sound

Cons

• Can become harsh with aggressive recordings or too much gain
• Soundstage and imaging are less expansive than some competing open-back headphones
• More particular about amplifier and source pairing than the GS1000
• Open-back design leaks heavily and is unsuitable for travel

The Signature Line Is Supposed To Sound Different

Understanding the S550 makes considerably more sense once you understand what Grado is doing with the Signature Line.

The Signature range began with the HP100 SE in 2024 and represents a newer direction alongside, rather than in place of, Grado's long-running Classic Series. The Signature family gives Grado more freedom to explore different sound signatures while its Classic headphones continue the approach the company has established over several decades.

The HP100 SE itself was created in recognition of Joseph Grado, who would have turned 100 in 2024. Joseph Grado's work, including the famous HP1000 headphones around 1990, is closely tied to the early history of high-end headphone listening.

That history matters because I initially approached the S550 expecting a variation of the familiar Grado formula. After directly comparing it with the GS1000, however, it became clear that the S550 is not trying to recreate that older sound, and I don't think it should.

This Looks Like A Grado Brought Into The Present

Visually, I prefer the S550, though the GS1000 has an appeal of its own. The GS1000 has an unmistakably classic high-end Grado appearance, and I suspect plenty of longtime audiophiles will prefer it precisely because they know what that design represents.

The S550 simply looks more modern. I particularly like the prominent Grado branding across the grille and the cleaner appearance of the mesh. There is still plenty of traditional Grado DNA in the exposed rods, circular wooden housings and relatively industrial construction, but it no longer looks like a headphone designed several decades ago. The wood also keeps that industrial appearance from becoming sterile.

Put the S550 and GS1000 on a desk together and I suspect someone who isn't already an audiophile would choose the S550 on looks alone, while an enthusiast familiar with Grado's history might have a much harder decision.

The construction also reminded me of just how recognizable Grado's basic headphone architecture has become. The exposed adjustment rods, headband and yoke arrangement even brought to mind headphones such as Audeze's LCD series.

I Didn't Expect This Much Bass From An Open-Back Grado

The bass was the first part of the S550 that made me reconsider what kind of headphone I was listening to.

Open-back headphones are often associated with spaciousness and air rather than physical low-end pressure, but the S550 puts considerably more emphasis on the latter than I expected. There is enough bass energy that I sometimes found it difficult to believe how much pressure an open design seemed capable of producing.

More importantly, this isn't loose bass added simply to make the headphone sound bigger. Bass notes carry real weight without turning muddy, which gives electronic music, hip-hop and modern pop considerably more drive than I normally associate with open-back audiophile headphones.

The GS1000 can also produce substantial bass, but it presents it differently. The S550 feels tighter, cleaner and more concentrated, while the GS1000 lets that low end spread into a considerably larger acoustic space.

The S550 Doesn't Have The Huge Soundstage I Expected

This was the second surprise.

If I put on something like the Sennheiser HD660S, one of the things I immediately notice is the space between instruments and how distinctly different elements occupy recognizable positions across the stage. The S550 doesn't present music in quite the same way.

Its soundstage is noticeably narrower and the presentation is considerably more forward. Individual elements can merge together more than they do on the HD660S, and positional imaging is not one of the S550's strongest characteristics.

What surprised me is that this narrower presentation does not come at the expense of detail. I can still hear individual elements inside a recording, including vocal reverberations, small ambient cues and details that are easy to overlook with less revealing headphones.

That distinction became important during longer listening sessions. The S550 isn't creating the impression of detail by spreading everything across an enormous stage; instead, it brings the entire performance closer while still retaining a surprising amount of information within that more concentrated presentation.

The Midrange Is Natural, But There Is A Lot Of Energy

If I had to describe the S550's midrange in two words, I would choose natural and energetic.

Vocals don't strike me as artificially colored, but neither does the S550 present them in a relaxed way. There is an immediacy running through the mids that contributes heavily to the headphone's overall personality, and with the right music that can be very exciting.

With the wrong music, though, it can become too much. Listening to Deftones exposed that limit particularly clearly, as distorted guitars could become overly aggressive and, depending on the amplifier and gain setting, move from energetic into genuinely harsh territory.

That characteristic extends into the treble as well. There is plenty of upper-frequency detail, but I wouldn't describe the S550 as universally forgiving. Recordings that already contain a lot of distortion or aggressive upper-midrange and treble energy can push the headphone too far, which is why I probably wouldn't choose it primarily for metal.

This Grado Makes Much More Sense With Modern Music

The more I listened, the more I found myself gravitating toward pop, K-pop, electronic music and hip-hop, and that is where the S550 really started making sense.

Its forward presentation puts vocals right where modern productions often want them, while the strong, controlled bass gives electronic beats enough physical impact to feel convincing. At the same time, the energetic midrange prevents everything above the bass from sounding recessed or overly smooth.

That made me wonder whether describing the S550 simply as a more approachable Signature headphone misses something more interesting. It feels as though Grado is using the Signature Line not just to produce a different headphone, but to evolve its sound alongside the evolution of music itself.

The S550 doesn't need to recreate the GS1000 because the GS1000 already exists.

The GS1000 Sounds Like A Completely Different Grado

Grado specifically suggested the GS1000 as the Classic Series counterpart for this comparison, and after listening to both, that choice makes sense.

The GS1000 uses Grado's much larger G cushions, while the S550 uses its newer B cushion. Beyond the physical difference, the two headphones immediately present music in very different ways.

The GS1000 has the kind of expansive soundstage I originally expected from the S550. In terms of width, it reminds me considerably more of the HD660S, but the GS1000 doesn't sound like the Sennheiser either. There is more bass and considerably more raw texture.

The analogy I kept returning to was a guitar amplifier. The HD660S can remind me of hearing a carefully reproduced guitar through good studio monitors, while the GS1000 is closer to standing in front of a Marshall stack. The guitar becomes grungier, vocal textures become rougher and there is more emphasis on the surface and character of the performance rather than making everything sound perfectly polished.

Another way of putting it would be the difference between a carefully controlled digital recording and hearing jazz in a smoky bar. The second isn't necessarily cleaner, but it can feel more alive.

The GS1000 Is For The Music I Wouldn't Choose The S550 For

That difference increasingly dictated which headphone I reached for.

For electronic music, modern pop, K-pop and hip-hop, I would generally choose the S550. For jazz, classical music, acoustic recordings and unplugged sessions, I would take the GS1000.

The GS1000 gives acoustic instruments more room to exist, and its larger stage makes the atmosphere of a recording more obvious. That slightly raw quality also gives guitars and voices an organic texture I really enjoy.

The S550 brings everything toward me instead, trading some of that spaciousness for energy and immediacy. Neither approach is inherently better; they simply make sense with different music.

The S550 Is Easy To Drive, But Surprisingly Difficult To Match

On paper, the S550 is not a particularly difficult headphone to drive, and that was certainly true in terms of getting enough volume. What surprised me was how sensitive it seemed to the equipment behind it.

The GS1000 proved considerably more forgiving. I could connect it to something as modest as the Fosi Audio ZH3 and still get a result I was happy listening to, while the S550 could sound noticeably flatter with less suitable pairings.

Pairing it with the iFi iDSD GR 2 brought considerably more energy and life back into the presentation, but there was another problem waiting at the opposite extreme: too much gain could make the S550 sound harsh.

This creates an interesting balancing act. The S550 does not necessarily benefit from simply having as much amplifier power as possible; finding the right source and gain level seems to matter more.

Balanced Didn't Automatically Sound Better

The detachable cable system is one of the S550's most welcome practical changes. Each earcup uses a mini-XLR connection, while the supplied Signature Silver cable terminates in 3.5mm and includes a larger adapter.

I also had a custom four-pin XLR balanced cable available, so naturally I tried it through my FiiO K9 Pro AKM.

I expected the balanced connection to be an upgrade. It wasn't.

I actually preferred the S550 from the conventional single-ended connection. That doesn't mean balanced is inherently worse, just as it doesn't mean 3.5mm is inherently superior, since amplifier topology, gain and listening level can all affect the result.

What it did reinforce was how noticeably the S550 responds to what is driving it. More power isn't automatically better, and in my setup the stock cable with the right gain setting simply sounded more natural and easier to listen to.

Changing The Cushions Really Does Change The Headphone

The S550 ships with Grado's newer B cushions, while the GS1000 uses the much larger G cushions. They are interchangeable, and Grado considers its cushions another way for listeners to alter both fit and sound depending on their preferences, music and associated equipment.

Naturally, I swapped the cushions between the two headphones.

After experimenting, I ended up back where I started. I preferred both headphones with the cushions they came with, as the GS1000's G cushions complement its spacious presentation while the S550's B cushions make considerably more sense with its tighter, more forward and energetic character.

That doesn't make cushion swapping pointless. Someone who wants to alter either headphone's presentation has a remarkably simple way to experiment, but for me Grado's original pairings worked best.

Getting The Headband Adjustment Right Matters

My initial impression of the S550's fit wasn't perfect. There is some heft to the headphone, and the rod adjustment system can make it feel much tighter than it needs to if the cups are positioned incorrectly.

The solution turned out to be counterintuitive. Rather than extending the rods farther, I shortened them until the cups only just reached the correct position over my ears. Once I found that point, much of the vice-like pressure disappeared.

After getting the adjustment right, I had no problem wearing either the S550 or GS1000 for longer listening sessions. The S550 still feels substantial, but it never became uncomfortable enough to interrupt my listening.

These Are Definitely Headphones For Your Own Space

There is no getting around the realities of an open-back design. Everyone in the room can hear what you're listening to, and you can hear the room as well.

I don't consider that a flaw because this is exactly how I expect headphones like these to behave, but it does define where the S550 belongs. This isn't a commuting headphone, and it isn't something I would take onto an airplane.

The S550 makes sense at a desk, beside a dedicated listening system or somewhere I can close the door and enjoy the advantage of an open design without worrying about anyone else hearing my music.

Final Verdict

The Grado Signature S550 surprised me because it wasn't the Grado I expected, and I think that's the strongest argument for it.

The bass is far more powerful than I anticipated from an open-back headphone, yet remains impressively clean. The midrange sounds natural but energetic, detail retrieval is excellent and the entire presentation sits considerably closer to the listener than something like the Sennheiser HD660S or Grado's own GS1000.

That forward character won't work for everything. Aggressive guitars and already-bright recordings can become harsh, particularly when the S550 is paired with too much gain. Its imaging also isn't as sharply defined as the HD660S, while listeners expecting the enormous open space of the GS1000 may initially wonder where it went.

Put on modern pop, K-pop, electronic music or hip-hop, however, and the tuning begins to make considerably more sense. The strong bass, forward vocals and energetic midrange give those genres an immediacy that the more spacious GS1000 approaches very differently.

The GS1000 remains the headphone I would want for jazz, classical, acoustic music and unplugged performances, where its huge stage and rawer, almost gritty character can give recordings an atmosphere the S550 doesn't try to reproduce.

The S550 does something else. It takes recognizable pieces of Grado — the open construction, wood, immediacy and unmistakable design language — and moves them in a more contemporary direction.

Even visually, that feels appropriate. I love the classic GS1000 aesthetic, and audiophiles familiar with Grado's history may appreciate it even more, but the S550 is the one I would rather leave sitting on my desk. The modern grille, prominent Grado logo and mix of industrial hardware with wood simply look fantastic.

If your library is dominated by modern music, I would choose the S550. If you mostly listen to jazz, acoustic, classical and older recordings, I would keep the GS1000. If your music collection spans both, though, the two headphones make a surprisingly convincing argument for keeping both.

The Signature S550 isn't Grado abandoning its classic sound. It's Grado realizing it doesn't have to have only one.

Frequently Asked Questions

How Much Does The Grado Signature S550 Cost?

The Grado Signature S550 is priced at $995 and sits as the more approachable entry into Grado's Signature family.

Is The Grado S550 Open-Back?

Yes. The S550 uses an open-air design. That means substantial sound leakage in both directions, making it much better suited to private home or office listening than commuting.

Does The S550 Need A Powerful Headphone Amplifier?

Not necessarily. It is relatively easy to bring up to listening volume. In my testing, however, amplifier matching mattered considerably more than outright power. Too little could leave the presentation sounding flat, while excessive gain could make its energetic tuning harsh.

Does Balanced Sound Better On The S550?

Not automatically. With a custom balanced XLR cable connected to my FiiO K9 Pro AKM, I preferred the S550 through the single-ended output. The result will depend on the amplifier, gain and listening level.

What Kind Of Music Is The Grado S550 Best For?

I found it particularly well suited to modern pop, K-pop, hip-hop and electronic music. Its strong clean bass and forward, energetic presentation work particularly well with contemporary production. For jazz, classical and acoustic music, I preferred the wider and more organic presentation of the GS1000.

Can You Swap Grado S550 Ear Cushions?

Yes. The S550's cushions can be exchanged with other compatible Grado designs. I tried swapping its cushions with the GS1000 but ultimately preferred each headphone with the cushions supplied for it.