Stax SRS-3100

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STAX SRS-3100 Earspeaker System : L300 + SRM252S

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500+ Head-Fier
Pros: Improvement in staging & imaging, and build quality vs older lambdas
Cons: Avoidable design flaw affecting fit (YMMV)
Preface: Since there is an abundance of well-written pieces on entry-level Stax already and the SR-L300 doesn't represent a significant deviation from the lambda sound signature, these notes are primarily concerned with the incremental changes in this iteration. If you're unfamiliar with the lambda sound, I'd refer you to @JustinBieber's SR-202 review on this page for a good idea of what to expect:

I've been meaning to check out the advanced lambdas given their departure from ye olde lambda design to see how Stax is doing and where they're taking their products. And so I picked up a SRS-3100 a little while ago. After spending some time with the SR-L300, I find it's two steps forward, one step back. Sonics first, then a once-over outside and in. Reference is another basic lambda, a SR-202 with SR-507 pads.


The most significant change to me was in terms of staging and imaging, as you may have expected with the new angled baffles. Space in all directions is pushed out a tad, left/right channels are pushed forward slightly, and the space between L/R and center is better filled in. So with a top-down perspective, suppose one was to represent the 202's acoustic volume as bounded by the aquamarine trace, relative to that the azure trace would be the L300. Nice job by Stax here.

Response from 2 to 4kHz is reduced a bit, resulting in things like vocals being a bit less upfront. This would be a welcome change for those who can do with a bit less shout and glare present in the upper midrange with previous lambdas. Bass on the 202 starts gradually rolling off at 80Hz, reaching down to 30Hz though at which point it's nothing more than a mere sputter. With the L300, roll off starts lower at 70Hz but drops off a cliff after 50Hz. In listening, I find bass on the L300 to be preferable, with a bit more thump.

With the redesign Stax dumped the "Basic" moniker and made a couple changes to the labelling. The serif font used struck me as slightly out of place, especially since everything on the box is in sans-serif fonts, apart from the Stax logo of course. The serial number sticker is now located at the bottom of the left baffle, instead of underneath the headband arc. Considering your eligibility for after-sales service is partially determined by this serial number, putting the sticker here where it's more susceptible to wear doesn't seem wise. And then there's the asymmetry.








On the gimbal you can see a vestige of the old design, a recess that mates with a restraining tab on the driver cage. A similar tab is now on the baffle instead and bumps up against the inside of the gimbal. Pads are now flat with the baffle responsible for driver angling. This allows for the drivers to be positioned at a more forward angle vs previous lambdas, thus, most likely, the change in staging mentioned previously. Initially I was concerned by how thin the pads were and if it would affect seal, but they posed no problems in and of themselves in practice. Apart from being angled, the baffle is also flared along the rear edge. Unfortunately, the sum of these design choices cause a critical problem with fit, at least for me, in that they restrict the top of the housing from rotating past the gimbal. As a result, clamping pressure is concentrated along the top, and the bottom of the pads will not sit flush against my cheeks. Weirdly, this also makes the sound seem as if it's coming from slightly above, since the drivers are no longer parallel to my ears, but at a slight downward angle. I'm a bit surprised that Stax made this design error considering they should be sensitive to this issue, what with their experience with the 4070. I assume this is common to all the advance lambdas.






Early 4070

Late 4070

A couple last points before taking things apart, the cabling is now the wide low-capacitance type, and the driver dust cover is a thinner more transparent mesh with plastic edging. Not sure why one side of the edging needed to be wider.



Another nice new feature is that the pads are easily removable. Taking off the pads, you can see that the baffle is hollow with ribs to support the structure. The pads are attached to mounting plates, held in place by pins that go into the baffle. Even with pads in place, the new design means that there is a gap between plate and baffle on the inside rim. On the baffle, you'll find a couple of ports that go through to outside air. Of course all this means that bass will suffer vs the old design where the pads are glued directly onto solid baffle plates, but my sonic impressions suggest Stax was able to achieve an acceptable result.
















Lastly, Stax gives us encapsulated drivers screwed to the baffles similar to the rest of the advanced lambdas. Stax transitioned to these resin encased assemblies for all models with the previous SR-X07 generation whereas earlier lambdas (eg SR-202) had bare drivers glued to the baffles instead. Still nice to see this kind of build even in a basic lambda.




So what did I learn? Well, it's encouraging to see that Stax continues to innovate and evolve their sound. There are some compelling ideas represented in the L300, but the execution leaves something to be desired. It seems to me their attention to detail is not quite up to the same standard of excellence as in the past. From a few recently published interviews and factory tours, I understand Stax has been hiring new employees, perhaps in an effort to get younger as their older original personnel must be hitting retirement now. It wouldn't surprise me if they were tasked with certain aspects of the advanced lambda project. Hopefully with future products we see a return to the impeccable craftsmanship Stax has so far cultivated.

A brief note on the SRM-252S since it's part of the SRS-3100 after all. For the tiny footprint, it's performance is not bad at all in driving lambdas. With the SRM-1/MK-2, there are subtle improvements in depth of image, clarity of sustain and decay, and dynamics in general, with more control at louder volumes. I'd expect even better results from the SRM-323X that is the current option a tier up from the basic amp but on the whole the SRM-252S is a perfectly capable little unit.
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100+ Head-Fier
Pros: Intimacy, detail, transparency, not even a grain of mud.
Cons: Stock comfort, channel imbalance below the second notch on the dial.
Warning I may speak poorly of a few headphones in this review, if you get offended, remember that this is just one man’s opinion.
The srs-3100 system is a combo of the SRM-252S amp/driver and the L300 earspeaker/headphone. The 252S is very nice and compact. I have considered upgrading this amp … but apparently, a proper electrostatic amp will cost $3000+. So I thought screw that and just compared the 252S to a 353X. the 353X opens the sound up a tiny bit... but from a quick blind test I only got 3 out of 4 right for choosing the 353X and the difference wasn’t major enough and surely didn’t seem worth the $900 I would have to pay for this new amp so I thought nothing more of it. (cough might be saving up for a BSHE)

Stock is not great, there is an oval-shaped mesh dust cover on the inside of the earcups that has an edge that might dig into your ears when you wear them. However, I found that if you rotate this mesh 180 degrees this gives your ears more room and no more discomfort. This is because the mesh’s surrounding plastic is asymmetrical, one side comes in farther than the other. This fix actually makes the headphones quite comfortable. However, I wanted more.
I had some Brainwavz pleather earpads lying around, and I thought why not. I tried affixing these pads onto the earpad adapter thing but something just sounded wrong. Probably from too much venting as now there was nothing stopping air from escaping around the edges as the brainwavz weren’t square shaped. So I just used some tape and put the earpads directly onto the earcups without any adapters with a small straw at the bottom (inspired by the straw mod) and the comfort was much better and so was the sound IMHO. More on that later as the whole review will be based on the sound with these pads on.
One thing to note is that there is channel imbalance below the second notch on the dial, and balances out just before you reach the second notch. I find that if I were to listen to music I would rarely listen below this and typically listen at notch 3 or higher. Only in modern and highly compressed songs would I turn it down back to 2, which is still perfectly fine, as it is only when I go below this that there is a problem. Plus this issue is very common and present on just about every analog knob if you go low enough. 
now with the cons out of the way…
Soundstage, Imaging, and Presentation:
Soundstage being the size of the sound "stage", Imaging being how well and easy it is to pick out each individual thing and separate it from the rest, Presentation being the package of these two things. A headphone's presentation is very important to me, there are many "high-end" headphones that I just can't stand because of this. Some of which are the LCD-X & Elears, as their presentation feels congested to me or everything just feels it its fired directly into my skull (no proper out-of-head sound). The SR207 and Utopias come close. 
In my head, the hd800s are the kings of soundstage. …well at least in terms of size but the SR009 are around the same level, speaking strictly of soundstage size.
However, coming from an HD650 as my last favorite headphone, I prefer a smaller soundstage with great imaging and presence. And for these reasons, the 009s and 800 just sound disperse to me and lacks the presence and intimacy.
(intimacy, the feeling that you can reach out and touch whatever’s playing). This the L300 does very well.
Speaking of just having a large soundstage. In this department, I prefer speakers. I used to think that headphones could never pull off a convincing presentation of something actually in front of you. But now...
Enter "Out Of Your Head" (OOYH) by Darin Fong.
What is OOYH? Basically, it is the best Virtual Surround software I've ever heard, and you should definitely try it out. The thing unique about it is that it is simulated from taking Binaural recordings from REAL speakers.
My favorite preset being PBN Audio Sammy Speakers which to my ears sound have the greatest transparency and depth of soundstage. (transparency: the perception that sound is not coming from your headphones, has to do with clarity, transient response, etc.)
This Software makes everything sound like a binaural recording. which makes out-of-your-head-sounds extremely convincing (basically everything). 
When Listening to music I switch it on and off depending on the song. But I leave it on all the time for classical/acoustic music.
With this software, it makes the HD800 soundstage seem obsolete to my mind, as just about any headphone can now have amazing soundstage.
Let me first say that I am very sensitive to highs, but I know them very well. I've been playing violin professionally and was part of an orchestra, so I know my string instrument timbres very well. 
In the string ensemble piece "Death and the maiden" by Schubert, with OOYH on and left right channels flipped (so that the violins are to the right and cellos are to the left), it is the single closest experience I have ever had to being in the center of the second violin section within the string ensemble without actually being there. If I were to close my eyes I can see the concertmaster (Roman Simovic in this case) giving it his all with sweat on his brow. The violins just sound so real so present. They are just so detailed, with such great clarity and transparency to produce what I illustrated above. However, the upper highs on the L300 might be a bit more in quantity than what might be considered "neutral" but I cannot find any fault with them for any acoustic instrument, as the slightly raised highs just come off as perhaps greater room ambiance. Only in synthetic music will it come off as a tad excessive, but keep in mind that I am sensitive to treble (which also scratches off basically all AKG and Beyers from my list).
Now compared to HD800, even though the HD800s have a greater quantity of highs. It is strange that in a side by side comparison, I find the hd800 to sound veiled. Possibly from the lack of detail compared to the L300. I was plenty surprised by this. (For those wondering the amp was an HDVD800).
HD650 remains my favorite for mids, not to say there is anything wrong with the mids on the L300s, just that I feel that the mids in the 650 are a hint colored to enhance the human voice and I think I prefer this. But the Mids are more transparent on the L300, It does no wrong here. Previous Lambdas have had issues here by sounding "shouty" I've experienced this personally, especially with the 407, but the L300 sounds much smoother sounding and do not have this problem.
Estats produce bass quite differently from other transducers. There is a distinct lack of pressure beating against your ear. Which some may call a lack of impact. While this may be true, I never really enjoyed listening to particularly impactful bass as I find it extremely fatiguing. I like my bass but I can live without it. With the Brainwavz pads, the Bass gets a nice boost extends a little further into the sub-bass and does not bleed into the mids at all. This boost really helps out with some modern music and is like adding a subwoofer to the room. True that there is a roll off at 50Hz, but this is not noticeable unless you are listening to a heavy synthetic bass genre like dubstep.
I find my only complaints are that I wish that there was no roll off simply because it is more aesthetically pleasing to see a flat line down to 20hz on frequency graphs. Now the Koss ESP950... its bass is the most *trigger warning* pathetic sounding bass I have ever heard … like a hamster fart ... ok not that bad but it flutters and chokes and has absolutely NO impact, Nada. 
As a Whole:
There is absolutely no blurring of notes, imaging is so good that you can just reach out with your mind and hear each instrument as a solo performance. The L300 are just so musical and well rounded. Everything it does, it does spectacularly. It's ability to reproduce the timbre of cellos, violins, the human voice is just fantastic, it does no wrong. With other headphones (non-estats especially) you have to take a leap of faith to believe there is an instrument in front of you. With these, they just appear out of thin air, and they just show you that they are right there in front of you.
While the L300 are not perfect, they are the closest I have had the pleasure of experiencing.
And that’s my review, It will be updated as I see fit, with new comparisons possibly.
Saw some people recommending songs in their reviews so.. this song sounds exceptional with these:
Billy Lockett - Wide Eyes 
(The first verse comes in and it's Just OH G***** ****)
Excellent review @RamenwithBroth. Concise and too the point. Do you mind sharing a picture of the pad mod you did? I don't quite understand what you mean, especially the bit about the straw. Thank you.
@Krisna13 Thanks, here's a pic of the straw sticking out from the bottom of the pad:
I taped a small section of a straw to the earpad, and the pads are secured to the earcups using a bit of scotch tape (pretty ghetto I know).
Front view:
(adding the straw might not be doing much in this case since I have the earpads pretty low and it leaves a small opening at the top, but anyways)

Stereo Skunk

Previously known as bledwhite409
Pros: Exotic/Exclusive, Warm, Rich, Smooth, Fast, Lightweight, Secure, Value
Cons: Transformer, Muddy, Dull, Unportable, Uncomfortable, Pricey, Higher volumes necessary for best sound, Panning at low volumes
Stax is a Japanese headphone manufacturing company probably most well known for their SR-009, regarded as the "worlds best headphone" by well respected audiophile/headphone reviewers Jude from and Tyll from

Z Reviews raves about the entry level Stax 2170 and Stax 3100 headphone systems

Head-Fi's own earfonia also has a well written review on the Stax 3100.

Now that we've had some context, it's time to respond.


I find Z and earfonia's report on comfort accurate. My ears, too, press up against the sharp plastic stator cover. I've only been using them for a week, but it's tolerable. After using them for a while, I notice that a ridge of my ear just fits within the notch on the stator cover, and no pressure point develops. I do not expect to modify the padding on the L-300s, instead, I look toward Stax's higher end models which may have better padding solutions. Unfortunately, I find the combination of thin earpads and considerable clamping force uncomfortable. At the same time, the L-300s feel secure. Unlike the HD800, the light weight L-300s feel agile, and you never feel as though they might fall, or that you have to be careful not to turn your head too fast. I also find the L-300s temperature warm, almost ear-muff like, which could pay off in colder temperatures, but is generally undesirable. Though the headband manages a very elegant and comfortable solution, overall the L-300 is quite uncomfortable.

Build Quality/Appearance
The L-300's construction is plastic. I can understand others' expectation for "better" build quality, though the weight savings are welcome on the head, and is almost in line with the thinness and light weight of the diaphragm it contains. Still, I'm even careful not to set them down too hard, or worse, drop them. (Imagine those plastic rulers in elementary school) I like the styling. It has a bit of a vintage look, but a look all its own. It looks clean. The build may be plastic, but if this is what it takes to lower the price, I respect the entry-level electrostat. The 3100's amp is quite handsomely built. Any criticisms of the fragility of plastic are somewhat tempered by desktop-tethering.

I don't mind taking full sized headphones with me to the office, in fact, I see it as a great way to continue to get value out of my headphones. I would rather have an excellent system that I take back and forth, than divide the budget into separate rigs and suffer any decrease in listening quality. The Stax, unfortunately, are unportable. I worry about dust and dirt collecting on the statically charged drivers and the plastic frame breaking in transit. Furthermore, I would also have to lug a 10 pound US-Japan voltage transformer around in addition to the 3100's amp. It's not impossible, but it was enough for me to not even bother trying.

Due to limited US supply, I purchased my system from Japan. The system was only compatible with 100V. I had to purchase a transformer from Amazon for an additional $40 (which isn't much when you're spending $700). The transformer I purchased ( though heavy, is compact, and tucks away nicely in cable management.

I managed to get the system for around $700 ( including shipping. This is cheaper than The seller, mmg0g0 was very easy to work with. For the price, I am happy with my purchase. The entire 3100 system is less than even a used pair ($800 as of 3/11/17) of HD800's without an amp. The 3100 makes for a unique listening experience that I find surprisingly entertaining. I also don't think many people have had the pleasure of trying Stax/electrostatic systems. The ticket to ride, in this case, is well worth, and risk of trying a less popular headphone, rewarded.

Perhaps a testament to the Ebay seller, mmg0g0, my package arrived in 4 days of shipping. Incredible. I've ordered things from Asia before that took a month to arrive.

Finally, we get to sound.

At lower (regular) listening volumes, a slight dip near 2.8khz, emphasis in the mid-high bass, and conservative highs, make the 3100 system sound downright dull and muddy, especially if your ears are acclimated to brighter cans like the HD800 and Beyerdynamic T1. You miss higher frequency information about reverb, and the "clarity" of vocals and instruments. Cymbals seem to get pushed back in the mix and snares no longer cut. Chris Botti in Boston is, in my opinion, already a smooth/warm recording, which benefits from brighter cans which bring out the lush acoustics in the hall, and make the horns and strings glisten and sparkle. Unfortunately, without listening at louder volumes, this is somewhat lost by the 3100. This can be pretty disappointing if you expected electrostatic headphones to have exceptional "clarity." With perceived mid and upper bass (80-120hz) emphasis, overall sound tends to lean a bit "thick." Furthermore, there's a lack of sub bass <50hz that I miss. This makes the 3100 system sound more round, and less full.

Also, the 3100's amp has the annoying habit of panning at low volumes. When wanting to listen at low volumes, you are forced to either listen asymmetrically or introduce another potentiometer into the signal path. I try to listen lower to save my hearing. Though cans like T1 and HD800 deter you to turn up due to ample (excessive?) mid and high energy, they avoid sounding muffled at lower volumes like the 3100. To hear a balanced amount of mids and highs, you get a considerable global increase in sound energy that may impact how long you can listen without fatigue or even hearing damage. That being said, at higher volumes, the 3100 system excels, however mids and sub bass remain recessed. (Sub bass may be a challenge for all open back headphones)

When you first hear the 3100, the thing that confuses you is how these cans sound FAST; fast in ways you didn't even know possible. You try to place a finger on how effortless it sounds, despite the dull frequency response. It teaches you that speed and frequency response are separate. At low volumes, the L-300s are transparent, and they're warm/dull too, almost oxymoronic. As you "learn" the 3100 system, you find that it's a much gentler listen than the T1 or HD800. Any songs you couldn't listen to on brighter cans, are now accessible (Michael Jackson - Don't Stop 'Til You Get Enough, bottle "clink" totally tamed!). Given the right song, and adjusted ears, the 3100 absolutely excels, even at the aforementioned lower (regular) volumes. The same dip in 2.8khz and polite highs makes for a very smooth presentation. Crisp, tight songs like Steve Gadd Band - Duke's Anthem, Michael Jackson - Rock With You, and Dire Straits - Money for Nothing present perfectly on the 3100, where the frequency response of the song and system are paired just right. The combination of speed and smoothness makes for a detailed yet relaxed listen. There are absolutely no sharp peaks or dips anywhere. (though there may be a slight peak in the highs responsible for some unnatural sibilance)

When you turn up, your highs "catch up," and the sound evolves to beautifully rich and crisp. It's almost a case of, "the higher you go, the better it sounds." If you like to listen at moderate-high volumes, and prefer a bit of scoop, these cans sound exceptional when you turn up. With the likely super-low distortion afforded by electrostatic technology, and higher volumes, "details" or softer sounds in recordings maintain their integrity. Reverberation, the brilliance of horns and hats, return at satisfying volumes with next-level transparency. Still, vocals can get buried with an overly-conservative midrange.

So was this purchase worth? It's a yes, with a but.

When I'm adjusted to the 3100's frequency response, and I'm listening quietly, I think I still wish for a tad less upper bass, more sub bass, and just a tad more high mids, but the more I listen, the more I just enjoy the music. There are moments, too, where the song's frequency response perfectly pairs with the 3100's presentation, and there are zero complaints. When I turn up, and find balance, everything sounds downright gorgeous. When I turn up for the Stax to sound their best, I do worry for my hearing, though. (It's not THAT loud, but still, It's a little higher than comfortable)

I find an irony that while the T1 and HD800 don't let you turn up without becoming harsh, the 3100's don't let you turn down without getting dull. With the T1 and HD800, you almost get all your highs "up front," or early on at quiet volumes. With the 3100, you start dull, and get your highs way later, at moderate-high volumes. It's like Zeos from Z Reviews says: "It hurts to listen (to the Stax) at anything but the loudest volume." Indeed you have to turn up to get a better balanced, full sound, and I do think the 3100 manages to still be easy on your ears at louder volumes, with slightly less listening fatigue. Perhaps each headphone has an optimal listening volume level. Maybe another way of looking at the 3100 inability to turn down, is the ability to turn up, because I sure can't do that with T1 and HD800. I wish either the HD800 met it's balance point a bit later, or the 3100s a bit earlier, because I don't want to HAVE to listen higher.

Having Stax, you feel a bit of exclusivity. I want to like them, though I miss the HD800 and HD650, and wonder about the frequency response of the other Stax models, and what the HD800S has to offer. I wonder if I missed an opportunity with the HD800 for a great low-volume listening can, or if the HD650s I returned are the more tamed version of the T1 that I'm now looking for. I find myself lucky to have both the 3100 and the T1s and understand why people have multiple cans. There really may be a perfect can for every occasion.

When the song, the system, listening level, and the mood all fit together, the system provides an experience that worth every penny, maybe more. Truly impressive clarity, warmth, richness, speed, and engagement. Though I'm quite happy with the Stax 3100, I'm left wondering if there's a system out there that's just as fast, more comfortable, and sounds just as good at lower volumes, so I don't have to worry about my hearing health. Volume aside, I do find that when I return to my T1s, I welcome the shape of the mid and high response. I think that instruments may present more cohesively. Over all, I'm happy to have taken the leap and tried this. The journey continues.

(Questions? Comments? Please let me know what else I can include in the review!)
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Ted, thank you for the response.
Have you considered getting any of Stax's previous line of headphones? I believe they will be much more to your liking, with no boosted mid-high bass and with a greater quantity of highs that should make it more exciting, less "dull" and "muddy" by your definition, at lower volumes. I also find the older series to be much more comfortable. The 507 is my favorite of these (although I prefer the L300 to them, for the qualities that you found were detriments) but other more vintage Lambdas are also brighter and can be found for cheap (~$200), since you do not need an amp to go with them.
*at higher volumes too^

Also the L500s are very similar sounding to the L300s, the biggest difference being better comfort with the pleather headband and thicker pads and the 5100 system's amp will do better at lower volumes because you can adjust the volumes of the left right channels independently.
Arthur Li
Arthur Li
Great review! There need to be more de-hyped Stax reviews like this.


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