Stax SR-Lambda (Λ)

Note: The rating and pros/cons above are for the normal-bias SR-Lambda. This review also makes mention of the Lambda Pro, which I also have in my possession.

Stax has always been a vaunted and controversial name in high-end audio. Their fans claim that no dynamic headphone can so much as touch the heights reached by the cheapest electrostat; their detractors malign their plasticky build, and plasticky, unrealistic sound. (As always, the truth lies somewhere in between.) But I was intrigued enough that when I had a free moment at CanJam NYC this year, I made a beeline to the Stax room to try out a couple of Staxen. I had always thought of buying some Lambda or other, you see. And after trying the L700 (and later on reviewing it - you can find that review on MajorHifi) I was moved to buy my own budget(-ish) Stax setup, an SRM-1/MK-2 and an SR-Lambda Pro that I ordered off Yahoo Auctions.

And the Lambda Pro came, and I liked it...but not that much. I was surprised by what I perceived as a sort of V-shaped sound signature, with a really quite recessed midrange and a really sharp, annoying treble peak at around 10kHz. The resolution was there, yes, but the tonality lagged far beyond what I had experienced with the L700. After digging around online, I discovered that, yes, the Lambda Pro tends to have a reputation for having a recessed midrange, and the original Lambda might be more my speed. So, intending to sell the Lambda Pro as fast as possible, I picked up a Lambda from another user on Head-Fi.

Yes, this is closer to what I was going for. I haven't yet had a chance to compare these to the L700, but I expect I'll find them to be more similar than not, because a lot of what I'm getting from the Lambda matches what I remember getting from the L700. But that's another comparison for another time.

The SR-Lambda is not totally linear. There are some emphases especially in the mids that can throw things out of whack from time to time - more in some recordings than others, though. Generally I do find that these sound "right," especially compared with the decidedly wrong-sounding Lambda Pro. They're great for classical, not really as plasticky-sounding as I've been led to believe, and have a great and agreeable tonality. Basically, the SR-Lambda sounds like a lambda, but a very good and competent one.

Bassheads need not apply. The bass is linear (do NOT believe any measurements of Lambdas before the current generation with rolled-off bass - the bass is rolled-off in the new ones, but not the old ones, and measurements that say otherwise were taken without a good seal), going audibly down to 20Hz, though it may be slightly reduced in level by the time it gets there. It has some impact and power, but the Lambda Pro does notably better here. But it's going to be a hell of a lot better than a stock L700, that's for sure. I'd say it's a bit better than, say, the Sundara as well. It's not "subby," though, so trve bassheads will hate these. I do have some trouble really discerning what's going on in the subbass with, say, Burial, but it takes bass EQ like a champ.

The midrange has that characteristic Lambda shout somewhere between 1kHz and 2kHz. This throws the tonality of instruments slightly off (but very slightly; I don't perceive these as very unrealistic at all). More importantly, the Lambda can play vocals kind of weirdly, emphasizing "ah" sounds more than it should. For a good example, listen to "Quitting Time" by the Roches - the "AH" part of "QUITTING TAAAHHHHIIIME" right in the beginning is certainly overpronounced and a little grating with these headphones. Looking at CSDs, there is a very small amount of ringing in this region in other Lambdas - I can't find a CSD of the normal-bias Lambdas, but I suspect its driver, too, is very slightly ill-behaved in this region.

Above that little emphasis, the mids are kind of laid-back all the way up to 4kHz. So the overall tone of the midrange is pretty agreeable, with that 1-2kHz bump lending a bit of an unnatural coloration especially to vocals. Piano can also be an issue, as well as flute, or any issue that plays notes in the 1-2kHz range - these notes will come across as hard. The emphasis is something like 3-4dB - not terrible, but not slight enough to go unnoticed. Very "sweet" midrange, whatever that means - kind of like a soft yawn.

There is an emphasis on the upper treble starting at around 8kHz and continuing up indefinitely (there is no roll-off); this is accompanied by somewhat of a hole from 6-8kHz. But while the treble in the Lambda Pro was near unbearable without EQ, it's fine with the normal-bias Lambdas. You sure get a lot of detail with these things, but with recordings that already have an emphasis on air it can be overwhelming, and cymbals as realistic as they could be, since they have a lot more "air" than they do "body." There might be a little smearing going on, but that could just as easily be my DAC (the Bifrost MB; I need to upgrade).

Soundstage is good. Pretty wide, airy (I keep coming back to that word, don't I?), with good instrument placement and imaging, though maybe not quite as wide as the Lambda Pro with its recessed midrange. The high resolution helps with staging, of course, because you get more of the reverberations of the recording space, giving you more clues to help localize instruments. Imaging is perhaps not the most precise ever. Some have accused these of having a "flat" stage, but I wouldn't entirely agree - I think the stage dimensions are fine and natural, personally. These are notably better at doing intimate recordings justice than the Lambda Pro or even the SR-009s.

OK, let's talk a bit about the Lambda Pro and some of the issues I had with it. My rating of that would be closer to 3 stars, and that's mostly because of unbearable colorations in the stock sound. For a while I tolerated it by using the EQ settings from the Stax ED-1, but to be honest, that didn't sound very good either - there's a 3kHz bump with that of about 6.5dB, which helps make up for the Lambda Pro's recessed mids, but it's too much. More importantly, the headphones didn't really sound fun with the ED-1 on. Tonal accuracy was broadly there, but there was nothing arresting about what was going on. Even more unfortunately, the Lambda Pros demonstrated that they were a bit less willing to take EQ than I would imagine. With EQ, the Lambda shout was still there, just subdued, but it would rear its ugly head every once in a while; and that 6.5dB upper midrange peak would get quite harsh from time to time. Treble retained a bit of its spiciness, too.

Build: The Lambda and Lambda Pro are both the cheaply-built monstrosities we associate with Stax, but since it was the 80s, I think it's forgivable. Frankly, I think the modern Lambda designs are forgivable, too. I like the boxy look, but I recognize that position puts me in the minority.

Anyway, more importantly, these are old, so you're going to get an old product when you buy one. On mine, the earpads have hardened considerably (though not so much on my Pro as on my normal-bias Lambdas). They're still very comfortable, though, as the clamping force is very light and the headphones themselves are pretty light too. There's also a list of "rules for use," so to speak, so that you don't damage the drivers. Don't push them into your head, don't play music without the headphones on, don't listen to them with wet hair (this one might be a myth, frankly), etc. When I was showing them to a friend of mine, I relayed this list of rules, and he said with very genuine confusion: "why do you own these?" It's a good question, and one that I consider every day. But if you want great sound, and you're not paying for that sound in money (because these are very cheap for what they offer), you're gonna pay for it with the fact that you own a piece of arcane technology that's very easy to destroy if you mishandle it. Channel imbalance is apparently common, although not a problem on my pair.

Value: For the "dynamic is best" faction, the HD600 may well still be a better value proposition than the Lambda. Obviously the 600 has less resolving power than the Lambda, but some will consider the timbre better and more natural (not me, although perhaps I should wait till I can A/B the two). But considering that the Lambda pretty much performs up to the standards of today's $1,500 L700 and can be had for $300 or under if you're lucky, I'd say it's pretty damn good. 10/10 value; you will not get better for the price except through a difference in taste or a stroke of luck (I feel like the ATH-AD2000, which I got for $200, is on the level of these, for example, but not in terms of absolute performance).

Conclusion: If you're planning to use the SR-Lambdas as all-rounders, let me just stop you there. They in no way give you an accurate picture of what your recording sounds like without heavy EQ - too heavy to be worth it, in my opinion. Instead, these are headphones that you get for the experience, for the "electrostat sound," to enjoy your recordings in a new way. And for that, they work wonderfully. Yes, the treble is hashy, and the midrange is uneven in the typical Lambda-ish way. The midrange unevenness can occasionally be grating and harsh, especially with operatic vocals. That said, they're definitely a cool thing that I'm happy to own.

1 star deducted for the Lambda shout & thinned-out treble. As for the rest, it depends on your taste. For $300, I'd say they're very, very good, but something like the HD600 or maybe the HE-500 or something would be a safer choice.

Hey audiophiles.

Audio set up used:

16/24bit uncompressed lossless music,

optical TosLink cable,

Nordost Brahma power cable,

Teac UD-503,

custom solid core copper silver gold XLR cables,

Stax SRM-006T,

custom solid core copper silver gold power cable.

This is a review of the Lambda Professional. These are just my impressions, opinions, views and experiences with them. I purchase all my many cans (all blind, risky but fun), no freebies or samples.

Design, build & comfort.

Well these use a thicker and stronger plastic than the SR-202 and Lambda Nova Basic, so slightly better build than them.

The design is all about practicality, yes the ear cups are tall and large (that’s because of the large oval stator). A non-detachable cable is something I do not like on any headphone.

The stock leatherette ear pads are decent but I would prefer more depth to them, my ears do not touch the inner metal grills.

The inner foam always deteriorates, a poor choice by Stax. I know they put it there to prevent dust and debris from the stators but the material was not suitable clearly. But Stax did change that to a fabric style one on their more recent Earspeakers, credit there.

They are very lightweight, plastic all the way.

And they are very comfortable, thanks to the lack of weight and the suspension headband (which stays in place).

Stax have been using this type of headband for many decades and for good reason (so many manufacturers need to adopt this style, honestly).

I personally do not like it’s retro look but that is not an important factor to me, comfort is far more important and these are very comfortable. You do forget they are on your head after a short while, just be sure to keep mirrors away. Haha.

Sound.

My Lambda Pros (LP) are almost 40 years old, forty!

I cannot believe how good they sound, sometimes old is pure 24K gold : )

Outstanding detail, treble, spaciousness, resolution, clarity, insight, airiness, imaging, highs, transparency, separation, etc.

It’s like a Focal Utopia (which I owned) but with a taller and more grand sound stage, it is quite something and such a wonderful experience.

I’ll give you an example of what I mean, Bachelorette by Bjork is a great test for cans. It has a lot going on during many sections, it gets very busy and this song catches out many headphones. I’ve heard it sound congested on quite a few high end cans but on my LP, it may be the best interpretation I’ve heard on any headphone at any price. And I’ve owned over 200 headphones over the years, that is saying something.

My LP may be the best can I’ve heard for low volume listening too, exceptional.

It can get a little bright but only when you crank up the volume. It’s like the cans are telling you you’re listening too loud, it’s trying to protect you.

The mids and vocals are so clear and transparent, a lovely tonality too.

The weakest part is the bass, if you’re coming from a bass emphasised headphone it may sound anaemic or subtle.

It definitely lacks some impact, depth, punchiness, extension and slam. But it is again very clean, tight and controlled. It has good size, warmth and fullness. It is nice but not great (you knew a negative was coming).

Oh, almost forgot to mention it’s extraordinary transient response. If you listen to fast pace music, well you haven’t been really unless you heard it on these. The way these things “stop and start” is really amazing, reference level. A good test would be Hunter Theme by Noisia, this track has caught out many high end cans and speakers.

They are also excellent value too, if you can get a pre-owned one in good condition. And they can last for many, many years as proven with my pair.

So I really, really like my LP and I’ve “only” heard it on a SRM-323S and SRM-006T. Not a KGSSHV Carbon, DIYT2 or BHSE (far too expensive for me, maybe one day though).

Highly recommended from me, happy listening all.

Update 1.

Audio set up used:
DCS Rossini Player,
Stax SRM-252S,
iFi iPower 12V low noise power supply.

Listening to Chan Chan by Buena Vista Social Club was marvellous. Easy to discern the different layers and elements of the song with the LP. This thing is just so damn clean! There is a purity to it’s sound, listening to Hello by Adele you can really hear the power in her voice. Very airy and spacious too.
Listening to Go Ahead by Alicia Keys, there is warmth on offer. Obviously not very hard hitting in the lows but very musical with the LP. A really nice tonality I find, especially in the mids.
Listening to Unravel by Bjork, you can hear the vulnerability and delicacy in her voice. There is a rawness in her performance here, quite beautiful and sweet. The LP shows that with ease with it’s stunning resolution.
Heart of Glass by Blondie was dreamy and surreal even, really good instrument separation by the LP.
Hurt by Johnny Cash was truly moving, you can easily hear his lips moving before he starts singing. Quite an epic song though, my favourite of his.
Listening to No Reason (featuring Nick Murphy) by Bonobo, there is a fullness to the sound. Pretty atmospheric and smooth, very enjoyable. It reached pretty low, the LP just never sound overwhelmed or flustered. Excellent composure and assurance by the LP.
Hearing Insomnia (Monster Mix) by Faithless, I just wish there was more power and presence in the lows but I know that will sacrifice the very high levels of detail and clarity on offer here by the LP. I love that song a lot, for me it’s a masterpiece. I guess you can’t have everything sonically but for me the Stax SR-007 mark 1 gets the closest I’ve heard.
Time by Hans Zimmer was another great experience, sweeping and involving.
Honey by Katy B & Kaytranada was really good, surprisingly good bass impact and extension. I really like Katy B’s tone and Kaytranada is very talented too.

Quick comparison with the great SR-007 mark 1, tested on the SRM-006T:
LP has a bigger sound stage, grander and taller. A bit more airy, clear, detailed but brighter and lacks some bass quantity.
007mk1 has an even more balanced sound, it's more nuetral. More musical, forgiving and pleasing. It has more bass presence and warmth, more fuller and smoother too.

Note: this review is for a Stax Lambda Pro. I'm not certain each review is for the same model here :/

This headphone (along with a Stax SRM-727a amp) is the finest audio experience of my life. If you're used to dynamic drivers, it'll be a shock the first time you hear what music is supposed to sound like. There is ZERO muddiness anywhere in the spectrum. Every frequency is reproduced cleanly and separately from the others. Voices and instruments sound so realistic, in unfamiliar music I'll often think someone is in the room with me, before realizing it's just the recording. Most concert venues don't sound half as clear.

If the sound balance right out of the box isn't what you're looking for, not to worry, they respond perfectly to an EQ, and will take on whatever sound signature you desire, at whatever volume (these sound just as good quiet or ear-bleedingly loud). Personally I like boosting 200hz ane below by 4db or so.

Most everyone talks about the mids or the highs, which are indeed world-class, and sharper and crisper even than any planar magnetic driver can manage. But for me (an EDM & hip-hop listener) the bass was the real revelation. Where even the best dynamic speakers produce a deep indistinct boominess, these can articulate the bass exactly, and you can suddenly tell the difference between a 20hz and a 22hz tone.

Even the sennheiser HD800 sounds slow and artificial sounding compared to the Stax. I haven't heard other electrostatic headphone systems (be it other Stax models, the Koss ESP950, or the absurd $10,000 Sennheiser HE50), but no dynamic, no planar magnetic driver can come close to doing what this Stax electrostat can.

Obviously your source matters, but even streaming soundcloud from the headphone jack on my phone sounds phenomenal through these. Using a hi-fi DAC such as the Mojo or GOV2+ is even better of course, but the gap between my phone (an LG V10 with a relatively great DAC to begin with) and those hi-fi dacs isn't nearly as great as the gap sounds when using regular headphones. I prefer a DAC that gives a lot of body to the music, such as the Hifiman HM601. Using a bright DAC might not be the best pairing.

While the astounding sound quality is the most important thing, I'd like to say a few words about build quality and comfort. The build quality is nothing special, they seem to be made of a cheap plastic, but I've learned that a cheap feel does not mean it's actually flimsy, but I baby mine anyway just in case. As these are the least portable headphone type on the market, that's not much of an issue. They will never leave the room where their amp is set up.

Comfort-wise, they are exceptionally comfortable. They weigh very little, and exert almost no clamping force on your head, but somehow they never slip off while you're wearing them either. The main issue related to comfort is the fact that they rely on static electricity to produce sound, and bumping your hand to the outside of the case can cause a quick grounding on that side, and you will only hear through the opposite side for a minute while it builds up a sufficient charge again. It's a minor issue that's inherent to the technology.

IN CONCLUSION, these are the best headphones I have ever heard, they put most $1,500 pairs to shame (ahem HD800 ahem), and if you know how to EQ for yourself, there is no reason you wouldn't be blown away too.