Getting to know Stax
Stax has been around: longer than you and me, most likely. Founded in 1938 in Japan, Stax made their first electrostatic headphones in 1960, namely the SR-1. Over the next 36 years Stax diversified production to include amplifiers, tonearms, CD players, DACs, phono cartridges and other loudspeaker products, but have remained synonymous with electrostatic headphones, which they call ear speakers.
Despite their cult status, in 1995, 57 years after the company was founded, Stax could no longer keep the business running. As Stax became insolvent, fans and fanatics were crushed. But it was not long until one of these said fans came to the rescue. The said fan happened to be at the helm of Edifier, a Chinese audio equipment company, and Edifier promptly acquired 100% equity in Stax, breathing new life to the Japanese legend. This was December 2011. The rest, as they say, has been history.
As of June 2020, the Stax product lineup consisted of seven electrostatic earspeakers, seven electrostatic amplifiers and accessories for these products including extension cords and an iconic headphone stand. Stax is extremely popular for their “Lambda” design as well as for their “Omega” series.
In fact, Stax commands a loyal, near-cultish following, like no other headphone brand. “Staxists”, as Stax fans are often called, are virtually a community within the larger HeadFi community. They make for extremely passionate audiophiles, and will own several of Stax’s headphones, including discontinued headphones. Worth noting that Stax’s discontinued headphones are considered collector’s pieces, yielding considerable value in the secondary market.
Moving on…to the 009S
Interestingly, the Stax-SR009s is not the current Stax flagship. It was the Stax flagship until the recent launch of the X9000. However, the X9000 is yet to reach many hands in western markets, since production lead time has been substantial, in a post-COVID world of parts shortages, manufacturing delays and increased shipping times. Therefore, it suffices to say that for the most of us, the 009s is still the standard with which to judge electrostatic headphones.
What does it look like and how comfortable is it?
The Stax SR009S are rather beautiful to my eyes. They are not as peculiar looking as some flagships such as the Abyss AB-1266 Phi TC or the Raal Requisite SR1a, but possess a rather conventional form factor with dual headband design. The design language is unmistakably Stax, which I favor.
The headphone and accessories reach users in a wooden box with the brand logo on it. The aesthetics are rather vintage, true to Stax’s reputation.
Build-wise, the headphone is made mostly out of machined aluminum and leather parts and the stators are now gold plated so build quality is rather solid and everything is well put together. There are plastic parts such as the outer headband and the slider mechanism. However, the build has lasted for most 009S users.
As for comfort, it hits it out of the park, for me. The earcups are soft and supple and the head strap rests nicely on my noggin’, and I can wear the 009S for hours. It’s comfort is at the same level as that of the HIFIMAN Susvara, which is also exceedingly comfortable.
But how does it sound?
In my early days as an audiophile, reading other people’s reviews, I used to just skip to the sound section. However, of late, I find myself reading more and more background about a headphone. Reading about headphones’ backgrounds constitutes yet another way for me to engage with the hobby.
A big caveat before we get into a sound discussion, pun intended, is that the source pairing is critical for Stax. The SR-009S is like an electron microscope, revealing flaws, strengths, particularities and peculiarities of any chain that it is plugged into. For instance, the first time I tried the 009S, which is not off the most suitable chain, the SR-009S still sounded lovely, but occasionally bright and somewhat bass-light. That chain had the Cayin i-DAC6 MK2 and the Stax amp SRM-007 tII.
The best chain I have heard with the SR009S is incidentally my own, which has the Holo Audio May as the DAC and the rather impressive Kevin Gilmore Solid State High Voltage (KGSSHV) Carbon as the amplifier. Stax headphones are known to play well with R2R DACs and the Holo May is arguably the best value among flagship R2R DACs with many reviewers claiming that they hold their own against DACs worth two or three times more. Meanwhile, the KGSSHV Carbon is well-known for its pairing with the 009 and its bigger brother, the 009S. It is a transistor-based amplifier that aficionados laud for sounding “tube-like”.
All my impressions below of the SR009S is based on the Holo May – KGSSHV Carbon chain. I do want to add that I am no stranger to the finicky ways of flagship headphones. In fact, I have wandered the streets of various cities and countries to find the right amp to pair with my HIFIMAN Susvaras, which were my first flagship headphone, and in many ways, my first love.
With headphones like the Susvara, every aspect of the chain matters, even the cable. That said, given how much the 009S changed character from one setup to another, I have to say that the Stax may be more finicky and chain-dependent that any other flagship I have tried.
Now, with backgrounds and disclaimers out of the way, let’s get into sound!
In my first few hours of listening to the 009S, I was quite struck by how the headphones have a tighter, deeper and more impactful bass than I was led to believe, from reading reviews. For context, I own an Abyss AB-1266 Phi TC. While not TC-level bass, of course, the 009S bass is an improvement over the 009 bass, and the improvement becomes more noticeable off the KGSSHV Carbon. In fact, I even enjoyed metal with the 009S, which I didn’t expect to.
That said, the midrange is the star of the show. The 009S midrange is beguiling, detailed, natural, and even enchanting. In some ways, it sounds similar to the Susvara midrange, which is saying a lot, given the Susvara is priced at $6000, and to me, it is well-regarded and loved for its midrange performance, especially off a good copper cable, and of course, when properly amped. With regard to the 009S midrange, I particularly enjoyed female vocals for how delicate and emotional they sounded. Male vocals sounded quite soulful and romantic, while not possessing the grunt of an LCD-4. This is a nitpick though, and overall, the SR009S is easily end-game for any lover of vocals and vocal-based genres.
The treble of the 009S is interesting, because on the frequency response graph, it looks jagged, uneven and peaky. However, within normal listening volumes, off the Carbon, the treble sounds very polite, laidback, and even relaxed, while being sparkly and joyful. I would say the treble off the 009S sounds similarly polite to the Susvara treble, and perhaps a bit more well-behaved, especially if you are using the Susvara with a silver cable. There is a dip in around lower to mid treble, which works rather well for me.
Overall, tonally, the SR009S strikes me as more neutral than the Susvara, which many consider to be the benchmark for a neutral-sounding flagship headphone.
Technical Performance: The Devil’s in the Details
Speaking of detail retrieval, the Stax SR009S could well be the current king of detail retrieval. I find it at least on par with the Abyss AB-1266 Phi TC, but often surpassing it, on better-mastered tracks that take advantage of the Stax’s resolving abilities. However, there is a caveat here and it is that the 009S is ruthlessly revealing of all flaws in a track’s mastering, and even the TC and the Susvara sound forgiving next to the 009S.
If you are at the mercy of the arbitrary mastering quality of streaming services, the 009S might make you switch tracks often. But this is not necessarily a dig on the 009S. If you are going to invest in such expensive headphones – why not be prepared by having at your disposal – a library of well-mastered tracks, either online or using FLACs on a hard drive.
And it’s not just detail retrieval where the 009S excels. The 009S is a pure legend in how well it portrays transient responses, which can make for a highly enjoyable listen if you listen to genres that token its speed. However, there is a downside to this speed. The decay and linger of instruments that token the bass frequencies, such as a kick drum, can sound a hair faster than what is natural. But again, this is a nitpick, and for most people, the speed will be an unadulterated win.
The other drawback to a 009S, and this is something you need to pay attention to, is that although it has decent dynamic slam, it is not particularly impactful or tactile, even off the KGSSHV Carbon. If you are coming from an HE-6, LCD-4, Utopia or an Abyss AB-1266 Phi TC, you shouldn’t buy a 009S thinking it will slam like these headphones. It is a headphone you buy for the entire package, and the entire experience, and bass heads are encouraged to audition before purchasing the 009S. Worth noting that Stax has other phones that have stronger bass, such as the 007 series.
For soundstage and imaging, the Stax continues to excel. Off the Carbon amplifier, the Stax soundstage is truly 3D or holographic, to use the oft-misused audiophile terminology. I was particularly impressed with the distance, layering and separation between lead vocals and background vocals on certain tracks, and just the beautiful body to each image on a stage. The soundstage width is not spectacular, but what is impressive is that the stage is thrown in front of you, instead of close to your ears, which gives the presentation a certain “naturalness”.
With regard to timbre, the 009S does well. It does sound like an e-stat: fast, ethereal, and on the softer side. It will sound similar to a Susvara off a silver cable (but very different to a Susvara off a copper cable). The e-stat timbre is on the mellower side, and not even the HE-1 has the tactility, crunchiness, bite, and hardness that dynamic drivers can afford, as well as particular planars.
So, who is the 009S for and who is it not?
If you have heard electrostatic speakers, then you would have a sufficient imagination for what an e-stat headphone sounds like. If you have not, but have heard the Raal Requisite SR1a, then that’s helpful, but not quite all the way there. Because although the SR1a and the SR009S share some traits, such as speed, merciless detail retrieval, and so forth, the SR009S is still its own thing. I find that it pairs best with vocal-based genres and works the best for those who listen to classical music, jazz, and occasionally, pop and select modern genres. Perhaps comparisons with other flagship headphones will shed more light on whether the 009S is for you?
Stax SR009S vs HIFIMAN Susvara: The Susvaras may surpass the SR009S in natural timbre and body of the midrange and better bass impact. However, the SR009S are a tad faster, and a hair more resolving, and can sound more technically adept. What you choose will come down to whether you want unbridled naturalness, in which case, you opt for a Susvara with a copper cable. But if you want a combination of naturalness with extreme detail retrieval and speed, and don’t mind a lack of tactility, then the 009S is an easy choice.
Stax SR009S vs Audeze LCD5: The LCD5 is Audeze’s latest flagship planar magnetic headphone. Overall, the LCD5 has much better bass and dynamic impact and slam than the 009S. But as was the case with the Susvara, the 009S is more revealing, faster, and a tad more laidback in nature than the LCD5. It is both more technical and laidback than the LCD5, and that is the 009’s party trick. If you like modern genres, you may opt for an LCD5. For others, the 009S may be your thing.
Stax SR009S vs Abyss AB-1266 Phi TC: The Abyss AB-1266 Phi TC is a very different beast from the 009S. This beast will slam and is ideal for rock and roll. I don’t much like the TC for genres that the 009S excels at, i.e., most acoustic and vocal-based genres. In fact, the TC might be ying to the 009S’s yang. In other words, they are two brilliantly complementary headphones. If you consider owning both, you may be all set and never need to look at headphones again.
Stax SR009S vs Raal Requisite SR1a: These headphones are the king and queen for detail retrieval and speed. I do think the SR1a is a hair faster and a hair more resolving, but the 009S has much bass extension and impact, when amped properly. Both headphones are exceedingly technical, and their technical prowess makes them worth adding to the stable. I adore both headphones and would be hard pressed to pick one over the other.
Stax SR009S vs Focal Utopia: The Focal Utopia is a delightful headphone and does almost nothing wrong, except for having a narrow soundstage width and a metallic timbre. The 009S easily bests the Utopia for stage width, depth, detail retrieval while the Utopia bests it for slam. The Utopia is very fast for a dynamic driver, but the 009S is certainly faster. If you like slam, go for a Utopia, but for all else, the 009S might be a better headphone.
In sum, the Stax SR-009S is a truly world-class headphone in 2021, and without hearing the Stax’s X9000, may well be one of the best headphones on the planet. It’s unique combination of musicality and technical prowess makes puts it in the Champions’ League of headphones, a league inhabited by the HIFIMAN Susvara, Abyss AB-1266 Phi TC, the Raal SR1a, and so forth.
The one caveat I keep returning to is the importance of the chain with headphones that are so revealing. But if you have that covered, or if you enjoy mixing and matching gears, which is a lot of what this hobby is about, then the SR009S may well be for you.
That’s it from me. Happy holidays, stay safe, and enjoy one last picture of the 009S. 😊
About the Author:
Sajid Amit is an academic, researcher and practitioner in international development by day, and audiophile night and day. His YouTube channel is called the Amplify Audiophile Show.