Stax SR-007 Omega Reference Series II Earspeakers & SRM-007 tII Energiser (Hi-Fi+ 76)

Headphone amps and amp/DACs
Stax SR-007 MkII Earspeakers,
Stax SRM-007 Mk II Kimik Energiser
Stax SR-007 Omega Reference Series II Earspeakers & SRM-007 tII Energiser (Hi-Fi+ 76)

Recently I had need, as one occasionally does, of a decent pair of headphones and, given that opportunity the audio glutton inside of me reached unthinkingly for the best available. Now, I’m no headphone aficionado, indeed I’m barely ever a serious headphone listener, but even I know that when you are talking headphones in audiophile and head-fi circles, Stax is a good place to start, so buoyed with the sort of received wisdom that borders on outright prejudice, I set about obtaining a pair of the legendary ‘phones. And like so many people who operate on the basis of assumption and urban myth, when reality bites it surely comes as something of a shock.

The ‘phones I was fortunate enough to lay my grubby mitts on were the Stax SR-007 Omega Reference Series II, placed one from the top in their six model range: fortunate because they served as a timely and salutary reminder as to just why Stax have provided the ruler against which all serious phones have been measured for the last 25-years; fortunate because they also demonstrated that far from being a second-class option when it comes to listening, a decent pair of headphones actually offers a very different and in its own way, just as valid view of the musical performance. I may not be a regular headphone listener, but time spent with the Stax has convinced me that they offer a real alternative to my main system--one with its own very real musical appeal--rather than just a last resort when the big speakers and the big system that goes with them is off limits for one reason or another.

Being electrostatics, the SR-007s naturally need their own matching energiser, the SRM-007 tII, which amounts to a standalone headphone amp, complete with three line-inputs one of which is balanced, it’s own volume control and a line-out so that it can be situated within a tape loop if necessary. It’s a tube design, employing four 6FQ7 valves and can drive two pairs of Stax phones if required from handy, front panel sockets. Styling has stepped straight out of a 1980’s JVC catalogue ? which makes it pretty much up to the minute.

The ‘phones themselves employ surprisingly large circular ear-pieces, in contrast to the traditional, rectangular Stax style of old. Look closer and the surprises continue. The beautiful leather pads have ‘D’ shaped apertures in order to get up close and personal with your ears, while they also rotate independently to further enhance the fit and comfort. Meanwhile, the outer, open face of each driver also rotates, allowing you to ideally angle each three-core ribbon cable. Given this beautifully engineered attention to detail, I was slightly surprised to discover that the headband is not adjustable. Instead, the wide support strap is simply elasticated. While initially sceptical, this arrangement proved remarkably comfortable in practice, and equally so on Louise’s far smaller head, so chalk up another to Stax’s long experience in the field.

The headset is reassuringly solid and nicely weighty, but all that attention to fit and comfort ensures that in use it never becomes a burden, while its gentle fit, a world away from the vice-like grip of studio ‘phones, means that sweaty ear syndrome is also a thing of the past. The supplied cord is a generous 2.5M long, but extensions are available should you need them. In its standard form this system will set you back a cool £2,995 but, if that’s not rich enough for your blood, then there’s also a tweaked or Kimik version, with a matched set of cryogenically treated tubes, EAT tube dampers all round and up to four days on the test-bench to make sure everything is perfectly balanced. This treatment adds a mere £300 to the ticket so, under the circumstances, why not?

Enough of practicalities, how do the Stax ‘phones sound?

Resident amp/speaker combination at present is the Berning Quadrature Zs driving the “one down from the Grandes” Focal Stella Utopia Ems, a combination that manages to combine phenomenal transparency and resolution with real scale and dynamic range. It’s an impressive and imposing set up. Compare that to the Stax system--which nominally sets out to do the same job--and you might think the result is a foregone conclusion. But you’d be wrong. Sure enough, the Stax ‘phones can’t match the sheer power, the staging and the immersive presence of the big amp and speaker pairing, but there are other areas in which they can teach us a thing or two. Detail and intimacy are traditional strengths of both electrostatic transducers and headphones, and it’s no surprise to note that the Stax take these attributes to the extreme. But that alone doesn’t justify their status as a genuine alternative to more conventional replay systems. That comes from another attribute entirely--the elimination of the listening room.

Even the best-behaved rooms have an impact on what you hear. What the Stax ‘phones do is demonstrate just how big that impact is. Listen to a piece of music on your main system and then listen to it via the Stax; note how much clearer the musical phrasing is, the subtle shifts in level that characterize the playing, the ease with which you can follow the musical line. Now, both my system and the room lean towards clarity and a direct, explicit presentation, shorn of bass thickening or cosy richness. Yet the Stax still present a noticeably more connected and directed version of the musical performance. To quote a phrase, they let you hear the conductor--and I’m not referring to his breathing or tapping feet, but his musical influence, binding the orchestra and music as a whole.

The effect is program dependent. The bigger and more complex the work the more obvious it becomes, so downsizing from the Brahms violin concerto to Bach mitigates the effect, but it doesn’t eliminate it. It’s just not as obvious. Downsize again to girl and guitar and you can barely pick it up, even when you know what you are looking for. Here the difference tends to get swamped by the contrast in presentation--perspective and acoustic versus detail and immediacy--with the speakers’ more naturalistic musical viewpoint carrying the day. But as soon as you ramp up the number of instruments or the musical density, the ‘phones start making ground and it’s not long before their particular appeal starts to vie for your attention. Am I about to give up on my loudspeakers? No. But I am thinking that it’s about time I invested in some serious headphones, not because they sound better than the speakers, but because they offer a different perspective. That perspective lays bare different aspects of the music, performers and their performance. It’s not just about detail, but what that detail can tell you, and in some cases that’s a night and day difference. Just try Neil Young’s Road Rage on for size and you’ll exactly what I mean.

Right about now the naysayers and “everything should be free on the internet” brigade will be spluttering their outrage at the proposition of spending more that £3K on a set of headphones. After all, you can pick up a set of ‘phones for a lot less than these will set you back--and they too, will eliminate the listening room. But there’s more to this than simply stuffing the speakers in your ears. Not only is there the question of the quality of the hardware involved, the transducer technology and the implementation, but there’s also the issue of the precise relationship between the driver and the ear canal. With a speaker that’s connected this intimately to a device as sensitive as the human ear, tiny differences will become readily apparent--with potentially ruinous results. Where the Stax score--and what you are paying for--is not just the engineering that’s gone into the electrostatic drivers and their energizer, but the thirty plus years of experience that informs the placement of those drivers relative to not just your ears, but the whole range of human ears and the heads they’re attached to.

That’s the really scary thing. Just as a loudspeaker manufacturer has to make certain assumptions regarding the range of rooms his products will appear in, and average their response as a result, the headphone designer is faced with the self same compromise, and although the variables are smaller, so too is the margin for error. The thing that impresses me most about the Stax is not the level of performance they achieve (which is impressive enough) but the utter consistency with which they do it, irrespective of the listener’s size or shape.

Stax refer to their systems as ‘earspeakers’. It’s an attempt to separate them from the run of the mill ‘phones with which we are all familiar, but it also reflects the level of performance they have achieved. Headphones have never been treated particularly seriously in hi-fi circles, as reflected in the slang moniker ‘cans’--redolent with image of tins and bits of string. That’s changing, largely driven by the iPod revolution, but that’s still predominantly a budget concern. What the Stax ‘phones demonstrate is that it’s time to raise our sights and enjoy the lessons that these earspeakers (and their competitors) can teach us. £3K is a lot of money--but it’s a lot less than a pair of Quadrature Zs and the Stellas! Besides which, there are four more affordable models in the Stax range. Give them a whirl; you might be surprised, you might be seduced, you’ll definitely be impressed.


Stax SR-007 Mk II Earspeakers & SRM-007 Mk II Kimik Energiser
Price: £3,295

Distributed by:
Symmetry Ltd
+44(0)1727 865488

US Distributor:
Yama’s Enterprises, Inc.

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