eric schmiedl photography

(Not photography related.)

A series of reviews I wrote some four years ago, comparing the Sennheiser HE90 “Orpheus” headphone with a number of others in its price-no-object class. Yeah, I used to be a headphone audiophile… and yeah the language gets a little overblown (the HE90 headphones originally went for $7500 a pair). Originally posted to Head-Fi, but recent downtime over there suggests these need a new home.

Reviews after the jump.

Associated equipment:
Kevin Gilmore Solid State electrostatic headphone amplifier with outboard high-end Condor linear +/-15V supply
Audiogeek Nitrogen cables
Arcam CD72T CD player though during the course of the review the headphones were compared on a broad range of sources from the 47 Labs Shigaraki transport/DAC to the Rockport Sirius III turntable. (yeah, the $90,000 one)

The Contenders
The Sennheiser HE90s are supremely comfortable. You barely notice that you have them on; there is a slight ring of pressure sensed around the ears and on the top of the head, but otherwise – nothing. The Sennheiser HD600s were evidently designed on a similar principle of fit, yet in comparison the HD600s feel tight, cheap, and crude. Even the cord of the HE90 is supple and flexible, which is a surprisingly nice feature since it doesn’t pull on the headphones.

The Stax SR-007 (Omega 2) are an entirely different animal. They use lambskin ear pads, which are very comfortable for about an hour before they start getting warm, at which point I either switch to the HE90s (which are good for hours) or open a window to cool the room down. The headband is supremely well designed — I don’t feel it at all. It requires no adjustment, unlike the HE90 headband that extends and retracts much like the HD600 headband.

The Sound
The HE90 sound is one of fantastic openness, of space. Partly the result of the insane frequency response of these headphones – up to 100kHz – and partly the result of the slightly bright tonality, I have with the possible exception of the AKG K1000 never heard imaging like this from a headphone. The perspective of the HE90s’ can be one of the conductor, with the symphony stretching out before you, the choir behind it, and individual instruments in their individual places. The perspective of the HE90s’ can be inside the machine, with the band eerily blocking your way. It all depends on what the performers and recording engineers wanted – not what the headphone designers wanted. Nearly everyone – including several musicians –who has had a chance to hear my system with classical music or jazz has commented on how it sounds exactly like being in a concert hall; one particular audiophile remarked that it was an experience he’d never forget.

In contrast, the Omega2s have more channel separation than the HE90. This manifests itself as a wider soundstage that’s not nearly as recording dependent as the soundstage on the HE90s. The Omegas take the instrument placement of the HE90s and shove it out a bit further and towards the rear. Most noticeably, however, the Omega 2 soundstage is incredibly three-dimensional and detailed, in that the Omega 2 are one of the few headphones I’ve ever heard that actively distinguish between the sonic foreground and the sonic background. However, it is important to note that the Omega 2s don’t attempt to duplicate the wide-open quality of the Sennheisers. The Omega 2s give the impression that they are giving the listener the music, the whole music, and nothing but the music. There is a sense of airy space occasionally, but it is highly dependent on the recording—whereas the HE90s place every performance in a defined, physical space with its own characteristics, the Omega 2s often give the impression that the music is performed floating in a space with no boundaries. Overall, this might be considered an offshoot of the more relaxed tonality that the Omega 2s have. They don’t try to express themselves, they just let the music flow.

Like most electrostatic headphones, the HE90s have incredible detail. I have yet to hear any driver – dynamic, electrostatic, headphone, or speaker – that matches the level of detail that the HE90s are capable of. The snap and boom of the cannons in Tchaikovsky’s 1812 or the crisp snap of the drums in a Sousa march are reproduced at a level head and shoulders above anything else. The headphone’s greatest strength could, in fact be considered an offshoot of one of its greatest disadvantages. Unlike speakers, nearly all headphones have a close-in soundstage, with no instrument located more than a meter or two from the head. Yet the HE90s turn this into a great advantage both by surrounding the listener and by reproducing the recording as if through a magnifying glass. These headphones allow you to pay attention and notice every nuance, every minor detail of the recording in unmatched accuracy. Many recordings with less than stellar productions become glaringly obvious. Fortunately, the HE90s do not let their fidelity get in the way of the music. Elvis Presley’s Jailhouse Rock, for example, may sound grainy and crude on the HE90s – yet it loses not a whit of its fun toe-tapping quality! In fact much of the distortion that sounds harsh and sharp on other components is revealed as even and round, making the recording considerably more listenable without covering up or smoothing over detail.

On the other hand, the Omega 2s don’t flaunt their detail. In fact, I once remarked that it sounded more like a dynamic headphone than an electrostatic one! For one, they have a much slower decay than the Sennheiser HE90. When playing a sharp, instantaneous sound – such as the claps on Strauss’ Banditen Galop (Telarc/ Kunzel) – the sudden spike is accompanied by a greater degree of reverberation on the Omega 2s. [1] Indeed, the Omega 2s seem dark and dominated by their lower end when one first hears them. The detail and treble that one normally associates with an electrostatic design are eclipsed by a feature that isn’t normally associated with electrostats. The bass is, in short, mindblowingly, insanely, unbelievably good. Like a truly fine piece of chocolate, it is rich and addictive, yet it is not boomy or restricted to a single note. At times subtle, at times powerful and overt, it is by far the most amazing feature of the Stax Omega 2. Drum hits are clean, deep, and dry while cello and double-bass notes are vivid and alive, their harmonics reaching into the depths of the frequency range and revealing an entirely new dimension to the music. Many headphones require a bass-boost function to reproduce certain low notes, and as a result, normally audible parts of the bass-region are accentuated unnaturally. The Omega 2s, on the other hand, handle these notes natively and without any exaggeration, revealing the great and majestic elements of the music in a fashion that is nothing short of utterly breathtaking.

All this assumes that you’re listening to music where fidelity and sound quality was a serious concern throughout the recording and mastering chain. With discs like the Red Hot Chili Peppers’ “What Hits?!”, all bets are off. The Red Hot Chili Peppers aren’t known for their well-recorded albums, which cause the HE90s’ brightness to be accentuated out of all proportion while they shows a an incredible aversion to bass notes of any flavor. The Stax Omega 2, however, gets its groove on. The soundstage is rich and three dimensional with depth and breadth and incredible spatial separation. There is a sense that the performance is more than simply a recording, that it is actually there. To compare the CD with the Red Hot Chili Peppers live concert the reviewer attended would be absolutely laughable, of course – there’s no way a rock concert could approach this level of fidelity. The treble issues that I identified earlier with well-recorded music do not seem to be present at all with, uh, less-well recorded rock music. While the HE90 still take home the prize in the detail category, you just can’t beat the Omega 2 in naturality and fun factor. Radiohead’s “Planet Telex” sounds liquid and clear with a slightly warm tonality and absolutely no headache factor. Don’t even get me started on the bass. Deep, powerful, and incredibly addictive, it is probably the single biggest feature of the Omega 2s and definitely one of the reasons that badly recorded music sounds so damn good. To make matters ‘worse’, the Kevin Gilmore solid state amp easily puts out, so that at several points I found myself reaching for the volume control when I realized I had been listening at unwise levels.

This is not to say, however, that the Omega 2 are only good for badly-recorded music. The midrange of the Omega 2 is warm and liquid in the sense of the best vacuum-tube amplifiers. The music flows like water, while retaining a warm quality akin to a down sleeping bag on a cold winter night. The trumpets in Tchaikovsky’s Capriccio Italien (Dorati / Mercury Living Presence ) are clean and creamy, accompanied perfectly by the pizzicato bass and wonderfully pure, textured clarinets. Though the HE90s do have better detail, snare drums on the Omega 2 most definitely don’t lack texture and in fact the whole treble region has the high resolution that is a noted characteristic of electrostatic drivers. The soundstage is amazingly three-dimensional and precise down to the nanometer: the cymbals in Glieré’s Russian Sailor’s Dance (Telarc / Slatkin) stand on an island in the middle of an ocean of symphony washing around but not over them.

Similarly, the incredible detail, transparency, midrange (and did I say detail?) of the HE90s takes the meaning of the word “fidelity” to a whole new level. In my system, the HE90s present the recording as it is, in perfect detail with almost nothing left out and nothing thrown in. They are the single most transparent headphones that I have ever heard and, as such, are truly the reference standard by which all components can be judged. When I audition cable prototypes, it is the Sennheiser HE90s that reveal flaws and nuances that are almost inaudible on lesser systems. At the same time, the HE90s’ transparency makes for an immediate and gripping quality that makes it almost impossible to get work done while listening to certain recordings. (The DG/Gardiner/Orchestre Révolutionnaire et Romantique recording of Beethoven’s symphonies (all of them!) springs immediately to mind as an excellent example.) When it comes to sheer attack, the HE90s have it. Drum hits rise up out of nowhere with thunderous results; listening to a Beethoven symphony becomes akin to riding a canoe through a picturesque South American river with an occasional drop off Niagara Falls. The HE90s simply sound more real than any other headphone I’ve ever heard.

Throwing the HE60s Into the Mix

There is something in the Sennheiser bloodline that infuses their electrostatic headphones with a kind of magic unheard anywhere else in the headphone world. They simply and effortlessly get out of the way of the treble, allowing it a kind of space and headroom that I’ve seen nowhere else. The result is the sensation of listening to the music live – in an actual venue, with room acoustics properly rendered and without the hint of a suggestion that there is a recording and playback chain in the mix. Granted, they render any imperfection in said chain with as much fidelity as can be imagined, but somehow the brain excuses those imperfections as if they lie in the instruments or vocalists themselves.
The HE60 is much, much better than I expected it to be. I had previously heard it on the HEV70 and found it simply unacceptable, being extremely flabby in its bass and simply off in everything but the treble.Off the KGSS, the HE60 is close to the HE90. The HE60 is warmer with a more bass-oriented presentation that gives it a more intimate feel than the wide-open spaciousness of the HE90. Whereas the HE90 is easy on the mid-bass[1], the HE60 took lessons from the Omega2 here. (the Stax is still the basshead’s headphone, though.) The HE60 gets its warmth from the combination of this bump with a tendency towards less detail than the HE90. Don’t read too much into that, though — the HE60 is at least 90% of the HE90.

If each component in an audio system is a window on to the world of music, the flaw of the Baby Orpheus is that it is made out of plastic[2]. High quality plastic indeed, but a plastic that manifests itself whenever bass comes into play. Whereas the Baby’s elder brother allows not a single note to get in the way of another, the Baby has a tendency to bloom. A bass-note with any kind of midbass content is always brought front and center in the soundstage, and once it is there the note proceeds to open up its peacock’s tail and obscure our view – like the play of a bright spot of light on a slightly cloudy acrylic window-pane, the blooming mid-bass of the Baby Orpheus reduces the contrast of the surrounding notes.

[1] The HE90 has noticeably deeper bass response, though it is less prominent.

[2] The HE60 is not the same driver as the HE90. The HE60 is considerably smaller, the same size as the HD580/600/650. It also uses plastic everywhere, instead of the metal and wood of the HE90. The driver uses plastic spacers instead of phenolic.