Stax SR-007 MK2
Stax SR-007 MK2 (about $1,800 direct from Japan, either through Amazon or through eBay). enlarge. This free website's biggest source of support is when you use these links, especially this link directly to the SR-007 at eBay or at Amazon, or this link to all STAX headphones and amps at eBay (see How to Win at eBay) when you get anything, regardless of the country in which you live. Thanks! Ken.
The STAX SR-007 MK2 electrostatic headphones are among the very best headphones in the in the world. In fact, depending on your preference for tonal balance, the SR-007 MK2 may be the best headphones in the world.
The STAX SR-007 MK2 are also called the Stax "Omega II MK 2," as I'll clarify at Versions. I'll refer to these as both "Omegas" and "SR-007" interchangeably throughout this review; it's the same thing. Stax has also made a different line of "Lambda" headphones since the 1980s to which I'll often be making references.
With these STAX Omegas, you can just sit back and enjoy the music. There are no artifacts, no distortion, no resonances, no exaggerations, and nothing artificial added. There's nothing but the music itself as it was recorded. You can shut up and listen. It's like getting sucked up through the mic cable and right up into the Neumann U-87.
I can listen to these for hours and hours every day, and come back wanting more. There is no fatigue; just more and more enjoyment. Just as Stax promises, nothing but sweet, smooth, detailed and fluid music, so long as your recordings are that good.
With these Stax Omegas, I hear everything that's in the recording, good and bad. Musicians spend days, weeks, months and years getting everything as perfect as they can, and with these headphones, I can enjoy it all. The sound from these Stax is effortless and natural; whatever's there is what you'll hear. Nothing is missing or exaggerated, there is no distortion or veiling, and everything from subsonics to ultrasonics are reproduced as they should be.
These electrostatic headphones make obvious the huge variations in quality, dimensions and timbres among recordings. We music lovers realize that this is the way the recordings are produced, while audio hobbyists may be thrown into confusion thinking something is changing on their end from one recording to the next.
These SR-007 MK2 are more neutral than other STAX headphones, which tend to err on the bright side. These SR-007 MK2 are significantly less bright, with much less upper midrange presence and treble than the Stax Lambda Pro. These Omegas give a perspective of sitting farther back in the hall, while the Lambdas put you in the first row. Everyone's tastes differ.
If you want a softer, warmer, darker, smoother, more forgiving and less-harsh sound, ideal for classic analog recordings, classic rock or LPs, get these SR-007. STAX describes the sound of the SR-007 as "deep and powerful." I describe it as less presence and treble, and most people would say "more muffled" than the other STAX offerings. Don't read this wrong: these SR-007 have less treble than other STAX headphones, but those other STAX headphones usually have too much.
If you want a brighter, more etched and completely unforgiving sound, optimum for enjoying the very cleanest modern digital recordings, go for the much less expensive Lambdas.
I can enjoy every kind of recording for hours and hours on end with these Omegas, while the brighter Lambdas can hurt my ears with harsh recordings. These Omegas make everything sound extraordinary, while the Lambdas are quite directly harsh with harsh recordings.
Unlike the great-sounding but dinky and all-plastic STAX Lambdas, these Omegas are toughly built out of metal. I can take them on and off and set them down on a console with worrying about breaking them.
These SR-007MK2 are supremely comfortable for hours on end.
These electrostatic (condenser) headphones work on the same principle as professional recording studio large-diaphragm condenser microphones: a large, thin, weightless diaphragm floats between a perforated plate or two and is charged with a polarizing voltage. Heck, U-87s and these headphones both protect their large, high voltage diaphragms behind metal mesh.
Ordinary "dynamic" headphones like Sennheiser, Beyer, Grado, A-T, AKG and Ultrasone still glue diaphragms to old-fashioned coils of wire inside magnets. No one would record a symphony with dynamic microphones, so why would anyone want to listen to serious music with dynamic headphones?
Presuming you're in the market for the best, I shouldn't have to tell you how superior are electrostatic headphones. There is no conventional dynamic headphone, not the the Sennheiser HD800, not the Ultrasone Edition 8, not the Beyer DT-990, and not anything with magnets that compares with these STAX for critical listening. I've owned them all.
Amplifier choice also determines treble response with STAX headphones. As a capacitive load, electrostatic headphone frequency response will vary with the amplifier's output impedance. These SR-007 sound best with a brighter amplifier like the SRM-1/MK-2, while the Lambdas are fantastic with a less bright amplifier like the SRM-T1.
For their intended use, the STAX SR-007MK2 are a bargain at only about $2,400 brand-new. To get sound this good, this accurate and over this broad a frequency range through loudspeakers requires at least a $100,000 investment in speakers, crossovers and acoustic studio design. Even if you had speakers this good, setting them up in a domestic environment just can't compete unless you also feel like dropping at least $75,000 into acoustic room treatment to get flat response without room nodes down to 16 Hz. Heck, a typically clueless "audiophile" won't think twice about spending three times as much as these headphones just on speaker and power cables. If you can afford to throw money at fluff, you certainly can afford these headphones.
Unlike a fine car, home or camera, these headphones should last a lifetime with no need for service or maintenance. Feed the leather every couple of decades, and you're good. My 40-year old New SR-3 still sound great after 40 years. If you want these, get them.
Frequency response extends comfortably to well above and well below the range of human hearing, so the entire audible spectrum is handled effortlessly without any resonances or phase shifts.
In fact, if you want to hear an example of just how pure is the sound from these Stax Omegas, hold your hands over their side screens. The sound changes dramatically just from the sound reflected off your hands! Move your hands slowly away from the Stax, and you'll hear varying comb-filter effects. The 007 are so devoid of their own coloration that even the slight reflections from your hands add or subtract audible changes.
Want clear sound? You can see right through these headphones! Just stick one up to your eye and have a look.
These earspeakers (as STAX calls them) must be fed from a specialized high-voltage amplifier that provides STAX' now-standard 580 VDC bias. The SR-007 MK-2 work with any STAX adapter or amplifier with PRO (professional 580 V) outputs. They will work with standard 230 V bias from older adapters, but with reduced sensitivity and maximum output.
I've never seen any US retail dealers. In the USA, we buy these directly from Japan. Better than paying retail, if you hate them, most Japanese direct sellers offer a money-back return policy.
Stax started in 1959 with the SR-1. I won't cover the earlier models here; see STAX' site for the history leading to this SR-007.
The original version of the SR-007 was the SR-007 Omega of 1998. They look the same, except for colors, as the current models. I'm not reviewing this first version, but seeing how it uses the same drivers and STAX describes the sound the same way, I'll betcha they sound the same as the newest models of SR-007.
There was a slightly improved SR-007 Omega II made from 1999-2006.
In late 2007 the current SR-007 MK2 came out, differing mostly by having real leather earpads for the first time, compared to the vinyl earpads used on all other STAX headphones since 1959.
"Mark 2" really just means leather earpads.
More formally, these current SR-007 MK2 may also be referred to as the STAX SR-007 MK2 Omega II. Once you add that many words, you'll see any number of variations, like STAX Omega II SR-007MK2, etc.
All 007s are Omegas, and all MK2s are Omega IIs. Laymen will also swap "II" with "2." STAX doesn't use "Omega" when referring to these MK2, but others do. The completely illiterate will call these the "O2 M2."
STAX usually writes this model number as STAX SR-007MK2, while I prefer to keep a space between 007 and MK2.
This STAX SR-007 MK2 is the USA import version. It's all black, including the outer protective screens through which you can see the gold diaphragms.
The Japanese domestic version is called the STAX SR-007A, and is the same thing, except with silver housings and screens.
STAX does this to try to confuse importers and exporters; choose your favorite color and enjoy.
This USA SR-007 MK2 has its gold diaphragm visible throughout its protective rear mesh as seen at the top of this page, and seen from the side, looks all-black:
Stax SR-007 MK2. enlarge.
The STAX SR-009
Stax announced a $5,000 STAX SR-009 on 28 March 2011.
It uses a different transducer, and oddly, takes a few step backwards to an ordinary gimbaled headband with click sliders.
Push-Pull Open Back Electrostatic Headphone.
6 - 41,000 Hz (no tolerance specified).
170 kΩ at 10 KHz.
94 pF, including cable.
100dB SPL at 100 V r.m.s. at 1 kHz.
Optimum Bias Voltage and Amplifiers
Works fine at 230V DC, but with reduced sensitivity (92dB SPL at 100 V r.m.s. at 1 kHz) and corresponding 8 dB reduction in maximum output level.
1.) "L" and "R"printed at the cable entrance points.
2.) The cable is marked with a solid line for left, and dotted line for right, exactly as STAX has been doing since 1959.
Lamb leather on the faces.
Surrounds made of some other sort of leather; it all looks like the same nice leather as the earpads of the Ultrasone Edition 8.
The surrounding piece that slips into the recess to hold on the earcups is made of some kind of black plastic.
The insides have a slight "D" shape. The original Omegas had thinner, more rounded earpads, while these MK2 earpads have a thicker surround at the rear.
Cable and Connectors
Stax SR-007 MK2 cable and connectors. enlarge.
Very supple, flat cord.
PC-OCC (Pure Crystal Ohno Continuous Casting).
The dotted side is the right channel.
2.5 meters (8.2 feet) long.
Molded 5-pin plug, Stax SR-007 MK2.
Molded 5-pin plug.
Raised black index.
0º to 35º C (32º to 95º F).
0-90% RH (no condensation).
I measure 390g (13.5 oz.) without cable, 529.4g (18.675 oz.) with cable.
STAX specifies 365 g (12.9 oz.) without cable and 512g (18.1 oz.) with cable.
Included Case, Stax SR-007 MK2. enlarge.
Size: 284 x 264 x 150 millimeters (11.25 x 10.375 x 5.9 inches), HWD.
Weight (empty): 1,327.8 g. (46.835 oz.).
2011 August: About $2,400 direct from Japan.
Box Front, Stax SR-007 MK2.
Box, Stax SR-007 MK2. enlarge.
What's inside the box, Stax SR-007 MK2.
UPC & SKU
In better grocery stores in Japan, these are on the shelf in the home goods aisle.
STAX SR-007MK2 SKU and UPC: 4 996476 000452.
Sound Quality top
The STAX SR-007 MK2 is extraordinary, like most electrostatic headphones. It's warmer and less bright than most other electrostatics. The SR-007 Omega II MK 2 is natural, clean, open, delicate, powerful, and precise, all at the same time.
Everyone's ear differ, and on my ears, there is about a 4dB less response from about 2kHz and up on these Omegas compared to the Lambda Pros (the Lambda Pros have a lot of output at 2 kHz and above). Which balance is better or flatter or more correct depends on your preferences, your ears and your source material.
Stax electrostatic headphones win on subtlety. If you want to enjoy every nuance of your music across hours and hours of careful listening, these are your headphones. If you prefer something that boosts everything for a screeching 30-second demo spin, these aren't for you, although they do go extremely loud.
There is no distortion. Every instrument, voice and multitrack layer is heard distinctly, never mushed into anything else. Instead of loud walls of crud, one hears everything separately, regardless of how loud you enjoy your music.
For instance, voices in popular music are often doubled-tracked or chorused to give them a fatter sound, and this effect will come in and out on different lines. Casual listeners never notice this, while with these SR-007MK2, it's obvious.
Listening with these headphones, all the distortion and coloration of conventional speakers and headphones is stripped away, leaving only pure music. I hear no distortion on sine waves at any level.
If choral masterpieces are your thing, you know these are up your alley, and likewise, if Metallica and Aerosmith are for you, you may for the first time hear every one of the hundreds of mixed, deliberately distorted sound layers individually. You can separate every voice in the chorus, and hear distinctly every one of the hundreds of layers of sound added in multitrack recording.
Whatever distortion was in the guitar amp is all you're getting; you won't get any more by turning up these headphones.
These Stax headphones excel because they are electrostatic, which have numerous advantages over conventional headphones like most Sennheiser, Ultrasone, Beyer, Grado and AKG.
Unlike electrostatic speakers, these headphones play LOUD, easily hitting 118 dB SPL without distortion. The sound quality is spectacular, and they crank out more sound than I'd ever want.
Personally, I prefer headphones to loudspeakers, so this sounds better than anything I've heard over monitors working in recording studios.
One caveat from the professional world is that these headphones are often used to monitor classical recordings, but be careful. Since the sound is reproduced so cleanly, your brain thinks that it's in the original performance space, and it sounds great even if the microphones aren't well placed. In other words, these headphones may trick your brain into thinking that your recording is better than it really is. Yes, technical problems like distortion will show up first over these headphones, but more subtle things like sloppy mic placement might not become apparent as you get sucked into enjoying the performance.
The ultralight diaphragm ensures no acoustic energy storage, meaning that there is none of the time-smearing and resonances of other headphones to muddy the sound.
Since everything is so clearly rendered, and bass is effortlessly and completely reproduced, these need not be played loud. They sound great at soft levels. There are no resonances or short-term echoes hiding any of the music, so it's all audible at any level.
Bass is just about perfect to well below audibility.
Bass is never distorted, and never rings, hangs-over, resonates, doubles, or does anything other than reproduce the sound as recorded.
These Stax Omegas easily reproduce subsonics without distortion, but since our body doesn't feel it, we can't hear it. Heck, I can feed a Stax amp with a 16 Hz sine wave at 100 mV and run it at full gain (probably 100 V output), and still not hear any distortion; the SR-007 just gives you 100 dB SPL at 16 Hz and looks forward to the next note.
Unlike my Beyer DT-990s, no matter how loud I crank these with low bass or subsonic test tones, I can't get them to buzz or to rattle.
Compared to the Stax Lambda Pro, there is very slightly more bass around 50-90 Hz, and slightly less at 20 Hz, but if you press these Omegas to your head, 20Hz comes in even more strongly than on the Lambda Pros.
It could be my imagination, but the soundstage seems to extend slightly out of my head compared to most headphones.
Otherwise, the soundstage is what we expect from headphones.
I love it, and prefer it to speakers.
On-center sounds are solid, centered and coherent.
These are circumaural, meaning they sit around the outside of my ears.
These are extremely comfortable for all-day continuous use. They feel soft and warm, and there are no compression points to bind. The earcups are deep enough so that my ears don't feel as if anything is touching them anywhere.
There is no headband adjustment; it's magic!
The top harp is fixed.
The lower headband is attached with elastic. Thank goodness someone at Stax figured out that if you use elastic with the same force as the weight of the headphones, they will stay exactly where you put them. Put them on any sized head, and they stay there all day. This is so much better than having to screw with click stops as on every other headphone (and even the new $5,000 STAX SR-009).
The beveled earpads rotate 360.º Just turn them until they lie flat on your head. I prefer to have the flat part of the D-shaped cutout towards the back.
The drivers also rotate 360º separately from the earpads, so you can place the cord anywhere you like, even straight up.
Unlike other Stax headphones, these stay tight on your head as you move. You can look up and down and they stay put.
They seem to be sealed with no ear ventilation for the best bass response, and that wasn't a problem for comfort.
Mechanical Quality top
The STAX SR-007 Omega II MK2 are far better made than any previous Stax headphone; they're all metal.
There are no gimbals or pivots to flop around. Ear adjustment is via rotating the beveled earpads.
Even though each driver and earpad rotates on its own, everything stays locked as one piece as you handle these. Handing them to a colleague is simple; it's not like tying to hold a pile of delicate hummingbird guts as with most other headphones. The only addition I'd like to see is a rubber outer covering to protect thee Omegas when they're laid on a console.
Included Case, Stax SR-007 MK2. enlarge.
Yes! Finally an expensive headphone with a real case, not just a fancy box.
The case is only about 10½" (275mm) square, so it's much daintier than you think; it's half the size of cases used for rackmount gear.
The case is great for travel. You can throw it off a loading dock and your fancy headphones ought to be fine.
This case is so great that some rich guys are buying these just for this case. They use the case for other headphones, and throw away the Stax Omegas, of which they already own a few pair.
The case has no lock, but what would it do? The case is half the size of a briefcase, and has a big $2,500 HEADPHONES INSIDE plaque on it, and a handle. What sense would a lock make? A few layers of duct tape will do a better job against hoodlums armed with screwdrivers. If you're trying to deter theft of a portable object, make it look like trash.
These are the best looking, most comfortable and best-built Stax ever.
These Omegas are so much more comfortable and pleasant to use than the dinky all-plastic and vinyl Lambda Pros.
These Omegas have significantly less treble and upper midrange than other Stax headphones, which usually have too much. Tonal balance halfway between the Lambda Pro and these Omegas would be perfect. When I say "significantly," I mean significant to the very precise listeners who buy these for careful evaluation of recorded music; all these headphones sound great. It's probably only a few dB, which is significant to those who know dBs.
As these are on the dull side, they sound great with harsh or bright recordings that can be downright painful with the Lambda Pros.
I prefer these with the SRM-1/MK-2, with which these Omegas are neutral to slightly dull.
The New SR-3 has better low bass below 40 Hz (honest), but more congested highs.
The Lambda Pro also has slightly better low bass.
If you press the Omegas more tightly to your head, the extreme low bass (< 32 Hz) becomes stronger than the other STAX headphones.
The Ultrasone Edition 8 has more bass, but less bass below 30 Hz, and a much more closed sound. Any of the Stax sound far more clean and open than the closed Edition 8s.
As a bass and tuba player I pay a lot more attention to the very low bass. I doubt most people will ever notice any of the effects I hear below 40 Hz, and when the going gets deep, holding the Omegas more tightly gives me the best low-bass I've heard yet. Most people are happy just to get bass that has pitch and dynamics instead of just thumping; I expect it to be most of the music. For most people, even sitting on your head all by itself, the SR-007s will have slightly more bass where most people hear it than other recent STAX headphones.
I haven't auditioned the $5,000 STAX SR-009 yet, however it sadly returns to the old gimbaled mount and click-stopped headband, and comes with just a fancy box; not a road case. Since the Lambda Pros are a little bright, and these Omegas are a little dark, maybe the SR-009 finally have the perfect balance. We'll see.
Rotate the earpads until they lie flat on your head. I prefer to have the flat part of the D-shaped cutout towards the rear of my head.
The drivers also rotate, so place the cord outlets anywhere you like them.
Tonal balance varies with amplifier. It sounds best with a brighter amplifier to balance the Omega's relative lack of treble and high midrange (2k-16kHz).
I prefer these with the SRM-1/MK-2, with which these Omegas are neutral to slightly dull.
The SRM-T1 sounds marvelously smooth, which means much darker and distant because of less treble. In fact, with a dull recording and the SRM-T1, I preferred it with a slight treble boost in an iPod's iTunes/Music App's EQ preferences!
If you want to boost the midrange, try holding your hands outside to introduce comb filtering.
Your Mom Says Turn it Down top
Most of us unconsciously gauge safe levels by the amount of distortion that accompanies it. We crank it until it starts to distort, and back off.
A live rock concert is only 100-105 dB, and PA systems have varying degrees of audible distortion at those levels. These Stax Omegas have no audible distortion, even above 110 dB.
It's easy to crank them to insane levels and love it. Be careful if you're new to these: you'll thoroughly enjoy damaging your hearing, leaving you with permanent ringing in your ears, making high-fidelity something you'll never be able to enjoy again.
Watch for High Voltage when unplugging the headphones from an adapter, energizer or amplifier.
It seems easy to grab the pins by accident as you insert or remove the plug from a socket, and if you touch them while energized, you may get a jolt of 580 Volts.
Beware: these voltages stay in this equipment for a long time, even when unplugged. Be careful!
Charge Time top
Better than other, older, Stax headphones, these SR-007 came right up and sounded great as soon as I plugged them in.
Owner's Manual top
The owner's manual is a folding card, printed on the very finest laid card stock. It's as if you've received an invitation to an extremely special event or concert. Here's how it looks:
The STAX SR-007MK2 are extraordinary. They sound great with every recording, even harsher older recordings because they slightly downplay the upper midrange and treble. This gives these Omegas very smooth, creamy, velvety, warm, powerful and deep sound, although some might simply say duller or muffled. They stick to your head and are soft and comfortable all day long. They're not particularly light, but so comfortable that I forget I'm wearing them after a few hours. No other headphone does that.
If you prefer a brighter rendition with more treble and high-end, the less expensive Lambdas are better. I've used and compared these Omegas to the older Stax Lambda Pro; today's SR-207, SR-307, SR-407 and SR-507 are the current equivalent to the Lambda Pros. I have yet to audition these newest Lambdas.
For enjoying all recordings, get these Omegas. For enjoying very clean recordings, you may prefer the Lambdas because they're brighter.
For professionals needing to hear anything and everything wrong with a recording before it's released, get the Lambdas because their added brightness makes anything bad obvious. You can hear so much more wrong with the Lambdas.
Want incredible sound from your iPad or iPod? Presuming you've made good transfers, any 99¢ 3.5mm to RCA cord between your iPod and the back of any Stax amplifier will quickly send you to goosebump territory. Transducers this good quickly make you recognize just how misguided are "audiophiles" who waste their time chasing cables or magic power cords instead of just getting some good electrostatic headphones.
As I covered at the beginning, these are a lot less expensive than speakers, and a lot less expensive than the baloney on which many audio hobbyists throw away their money. The poor man always pays twice.
Heck, professionals don't blink an eye spending three times as much on a decent pair of basic microphones. (U87s have been a standard in every studio for many decades.)
Because these are still so new and uncommon, used Omegas sell for about the same price as brand-new, so I wouldn't bother waiting for a used pair to come up. Heck, I've seen used ones sell for more than new, all on eBay.
For a fraction of the price, a used set of Lambda Pros or new modern Lambdas aren't as tough or comfortable, and sound just as good. In fact, many people who prefer a brighter sound will prefer the Lambdas.
The biggest advantage of these expensive Omegas over the Lambdas is comfort and solid mechanics. Sound quality is extraordinary on all of these; the differences between the Omegas and Lambdas is brightness and plastic. If you want brighter sound, you'll prefer the Lambdas, and you can get used Lambdas for $250 if you know How to Win at eBay.
If any of these is still too expensive for you, see How to build your own electrostatic headphones.
If you find this research helpful, this free website's biggest source of support is when you use these links, especially this link directly to the SR-007 at eBay and this link to all STAX headphones and amps at eBay (see How to Win at eBay) when you get anything, regardless of the country in which you live. Thanks! Ken.
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