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    Josh Mound

    ZMF Atrium Headphones Review


    Certain headphones become “must hear” touchstones for audiophiles seeking a neutral frequency response. The venerable Sennheiser HD650 is perhaps the most prominent example, with something like the Focal Utopia a more recent entrant.


    Are these always the best or most engaging headphones? Not necessarily. As Audiophile Style readers know, I rate the ZMF Vérité (in its open and closed variations) and Rosson RAD-0 very highly and listen to both much more than often than either my Utopia or HD6XX, with the Vérité open comprising at least 2/3rds of my headphone listening.


    That said, the Vérité’s slight “W”-shaped tuning (particularly in its closed version) is at least something of an acquired taste, and the RAD-0 has enough of a high-end shelf that it’s fair to call it a “dark” headphone. As I’ve written before, I think the complexities of headphone creation (and measurement) make obsession with perfect “neutrality” a fool’s errand. But that hasn’t stopped headphone fanatics weaned on the HD650 from longing for a “super HD650” — a pair of headphones that comes close to the HD650’s frequency response but adds a cleaner and more impactful bass, subtracts some grain from the treble, and elevates the HD650’s detail retrieval.


    Well, with the ZMF Atrium, the “super HD650” is here and, to paraphrase Sidra Holland, it’s real and it’s spectacular. Even better, listeners can tune the Atrium to their individual preferences by swapping pads (incredibly easy) or the switching titanium mesh covering the driver (pretty easy) without losing the traits that make the Atrium such a wonderful headphone in its stock form.


    ZMF’s founder, Zach Mehrbach, has provided a copious amount of information about the Atrium on the company’s website, as well as in multiple videos. This includes extensive measurements of the Atrium (as well as other cans in the ZMF lineup), taken with both a Brüel & Kjær 5128 HATS rig and a Larson Davis AECM210/AEC206 fixture. Going the extra mile, ZMF also shows how pad type impacts each model’s measurements. (In a separate video, Mehrbach walks viewers through the measurement process, using the Vérité closed as an example.)


    It’s safe to say that no headphone company provides as many measurements or as much information about design to potential customers as ZMF does. Moreover, both of ZMF’s measurement systems outstrip my modest MiniDSP EARS setup.


    Given the above, while I’m going to provide some details about the Atrium’s design and present measurements taken with the EARS to provide frequency-response comparisons, the bulk of this review is a subjective comparison of the Atrium against the Vérité open and Focal Utopia, as well as a description of how various pad and mesh modification of the Atrium impact its sound.


    The Atrium, which currently exists only in an open-back iteration, slots into ZMF’s lineup as a co-equal flagship alongside the aforementioned open- and closed-variants of the Vérité. The Atrium retails at exactly the same MRSP ($2,499 USD) as the Vérité(s).


    The Atrium’s primary calling card is its sound and technology. But before we get to that, let’s do a quick rundown of the Atrium’s build and comfort.


    Like all of ZMF’s headphones (besides limited-edition resin models), the Atrium’s cups are solid wood. The cups are CNC-machined, then hand-sanded and finished. For the first run of Atriums, all models are cherry. Purchasers have several customization options, though, including chassis material (aluminum or magnesium), headband material, and pads. The most important cosmetic choice is between black grilles, which come with a natural cherry finish, and aged copper grilles, which come with an aged cherry finish (and cost a little extra).


    The review pair I received have the aged copper/aged cherry combination and are as gorgeous as I’ve come to expect from ZMF. The design on the Atrium’s grille has a leafy, bucolic vibe based on the rose windows of Amiens Cathedral, as compared to the geometric, Midcentury design of the Vérité open’s grille.


    As I did in my review of the Vérité, the main thing worth stressing about the Atrium’s construction is how solid it feels. The Atrium is nothing but wood, metal, and (depending on the buyer’s selection) leather or vegan leather. These are built to last, which is something I can’t say for many headphones in the Atrium’s price range. To that end, ZMF provides a lifetime warranty for the driver to the original purchaser (and a $250 driver replacement cost for those who’ve purchased a ZMF headphone on the secondary market). Cosmetic repairs are available at low cost.


    Anyone familiar with other ZMF cans will recognize the basics of the Atrium’s gimbal and rod adjustments. Like the Vérité, both provide an excellent range of motion to accommodate all head shapes. Because, under all that padding, the headband is spring steel, it can also be bent for better fit, both in terms of shape and clamping force. (Mehrbach has posted multiple videos demonstrating the proper way to adjust them.)


    Speaking of headbands, the Atrium did catch my attention because it sports a new headband. Like my Vérité, the Atrium’s headband has an inner leather strap that helps evenly distribute the headphone’s weight. But the headband itself is wider and more padded than the one on my Vérité. Whereas my Vérité’s headband is approximately 1.5 inches at its widest point, the Atrium’s updated headband is 2-inches across and has more cushioning. While I never found the Vérité to be uncomfortable, the wider headband on the Atrium helps keep the Atrium stationary on my head, even when I have it adjusted to have lower clamping force.


    In its stock aluminum chassis build, the Atrium weighs 490 grams, which is 60 grams more than the open Vérité (which comes with a stock magnesium chassis). However, it’s right in line with the Focal Utopia, which also weighs 490 grams. The Atrium’s optional aged copper grille adds 30 grams, while choosing the magnesium chassis reduces the weight by 34 grams. My review model weighs in at the advertised average. Perhaps due to the new headband, I never once felt as though they were too heavy. Nor did I develop a hot spot where the crown of my head touched the pad.

    ZMF’s ear pads — which are available both for its own headphones and several other brands — deserve special mention. The company takes pads seriously — in terms of construction, comfort, and how they can change a headphone’s sound. (Check out this amazing guide and FAQ on ZMF’s website.)


    Speaking of sound, the technology utilized in the Atrium departs from the Vérité in several ways, despite the fact that the Atrium’s impedance (300 Ohms) is exactly the same as the Vérité open’s and the added fact that its sensitivity is only one dB less than the Vérité open’s (96 dB vs. 97 dB). First, while the Vérité uses a Beryllium-coated PEN driver and N50 magnets, the Atrium uses a biocellulose driver and N52 magnets. According to Mehrbach, “Biocellulose drivers have always captured my attention. Their innate ability to be dynamic, punchy, and weighty, while also retaining a lifelike timbre allows the listener to be fully immersed in the sonic landscape. The challenge in any driver design is to retain a proper frequency response while maximizing the sonic capabilities of the moving coil.” That’s where the biggest innovation embodied by the Atrium comes into play.


    ZMF’s new patent-pending damping system allows the company to squeeze the maximum resolution out of the driver and have greater control over what the listener ultimately hears. As the company explains:


    Why damp the back of a driver? During the negative impulse a dynamic driver pushes back away from the listener’s ear, and then sends sonic waves back towards the inner chamber of the headphone cup.  How these waves bounce around (or don’t bounce around) the interior of the cup influences what the end listener will hear. In both closed and open headphones, the right amount of diffusion for each driver to work optimally is important. In our tests, we found that simple porting of closed headphones, or keeping open headphones completely free of damping didn’t optimize each driver. The Atrium system allows us to choose how little or much damping is needed, which back waves we want to keep, and which we want to get rid of for the optimal acoustic headphone system.


    How exactly does this all work? A big part of headphone tuning is distances. How far should the driver be from the ear?  How thick an earpad should we use?  What should the ear pad volume be?  What should the cup volume be?  When you change any one of these single distances, it affects the other, and complicates the damping and airflow systems of the headphone.


    With the Atrium damping system for open headphones, it allows us another layer of optimization, making sure that the airflow and damping system is perfect for each driver.  With so many possible damping materials in existence, from foams to alternative materials and beyond, the placement method of that material that the Atrium system imparts, allows the designer the ultimate voicing of each system.


    Just as the drivers themselves are matched for consistency, the damping material is laser-cut and weight-matched for each pair of Atrium “to ensure accuracy.”


    While the details of ZMF’s technology is contained in its patent application, Mehrbach was kind enough to give me a tour of ZMF’s office and workshop when I was in Chicago last month. There, I saw bins filled with the various damping materials — precision-cut into a variety thicknesses and shapes — that Mehrbach experimented with before landing on the Atrium damping system, which uses a type of Visco foam. The Atrium also uses a Titanium mesh to cover the driver. There are two varieties of the mesh —solid and perforated — which alters the amount of treble. (More on this later.)


    The tuning of the Atrium was guided by both the aforementioned measurements and by ear. As Mehrbach explained in one of his videos:


    I know a lot of you are like me — that when you put on a headphone you want to make sure you can still feel the weight of the music, and that it has that tactile [feel]…. When a low bass note comes, you can feel it rumble a little bit instead of just hear it. The atrium damping system, by giving me that multi-layered way of acoustically designing the system, is what lets me have that linearity of sound while still being able to feel the timbre and tactile…physical nature of sound as I’m listening to the headphones.


    To me, that quote best summarizes the overarching experience of listening to the Atrium.


    The pithiest description of the Atrium’s sound is “visceral-yet-nuanced.” Room treatment provides and imperfect analogy. Just as carefully deployed absorption and diffusion can smooth out an in-room frequency response, tame resonances, and allow a great speaker to reach its full potential, the Atrium sounds more in control of the source material than perhaps any headphone I’ve ever heard. Decays are natural, imaging is precise, and the background is pitch black.*


    In a change from my usual practice, I decided to conduct some of my critical listening of the Atrium prior to taking measurements, so as not to let the measurements influence what I heard. I did this, in part, because Mehrbach warned me that the treble on the Atrium measured very differently depending on the fixture used. That’s not at all uncommon. When I reviewed the Audeze LCD-1, Karthick Manivannan told me the same thing. I also decided to listen before measuring because, as we’ll see shortly, deciding where to normalize a comparison graph can not-so-subtly influence one’s perception of the differences between headphones.


    In my review of the Vérité, I pitted the Vérité open (and closed) against the $4,000 U.S. MSRP Focal Utopia. As I still have all of these headphones on hand, I want to update these comparisons by adding the Atrium to the mix. For these initial comparisons, I’m listening to the Atrium in its stock format: perforated lambskin Universe pads and solid titanium mesh. The gear used for this controlled listening comparison were a Crane Song Solaris DAC feeding a Benchmark HPA4 headphone amp. (At various points, I've also used these headphones with various DACs, as well as Schiit Ragnarok V1 and Auralic Taurus MKII headphone amplifiers. All three of the amps mentioned have plenty of power for the ZMF cans.)


    Naturally, the first track I used, “I Have Finally Come to Realize,” comes from Van Morrison’s transcendent 1998 collection of studio outtakes, The Philosopher’s Stone. As I wrote:


    The delicate opening acoustic guitar strums from John Blakey are panned hard left and right. Recorded at the Record Plant in Sausalito, California, in 1975, both of the guitars are close-mic’d, and each individual string should be easily distinguishable through a good setup. Both the Utopia and Vérité open easily clear this bar. There are some slight differences in sound, however, that speak to important tonal differences between the headphones. With the Utopia, the guitars sound as if they’re mic’d slightly higher up the fretboard than on the Vérité, which offers a touch more sound from the body of the acoustic guitars. Their presentation of the acoustics’ string articulation is uncannily equivalent. Likewise, due to the close mic’ing of the acoustics, there are some mild thumps when the strings are struck harder. Both the Utopia and Vérité convey this transient impact well. 


    Adding the Atrium to the mix while relistening to both the Vérité open and Utopia (and adjusting the volume for its higher sensitivity), I was surprised to discover that the Atrium’s presentation of the aforementioned acoustic guitars leans more towards the Utopia’s than the Vérité’s. The Vérité sounds like it has the most energy in the upper-mids/lower-treble “presence” region. This gives the acoustics’ attack a little more bite than on the Utopia, which (as noted above) tend to emphasize the string noise (relative to the note or chord being played) a bit more than the Vérité does. The Atrium splits the difference. Acoustic guitars have less attack through the Atrium than through the Vérité, and the balance between the strings and the bodies of the acoustics strikes falls almost perfectly between the presentation of the Vérité and that of the Utopia.


    The Atrium also might do the best job of allowing the listener to hear differences in exactly where on the strings the guitarist in the right channels is playing. (He begins closer to the bridge, then moves up towards the neck as the introduction progresses.) Listening for other cues, it sounds like the Atrium also has a bit more upper-treble “air” than the Vérité, but slightly less than the Utopia. The slight tape hiss on this 40-plus-year-old recording, for example, is emphasized on the Utopia relative to the Vérité, with the Atrium falling somewhere in between.


    Moving further into the song. Here’s what I wrote in my Vérité review:


    As the rest of the band enters on “Realise,” the broad differences between the Utopia and Vérité open become more apparent. In line with the general observations of their frequency response differences outlined above, the Utopia offers more “air” than the Vérité. On the Utopia, the ambiance of the Record Plant’s room is more apparent, whereas the Vérité offers a somewhat drier sound. 


    The Vérité, for its part, hits much harder than the Utopia. Indeed, the Vérité’s overall macrodynamic advantage is more dramatic than the headphones’ respective frequency responses suggest. While no headphone can ever convey the visceral impact of something like a kick drum or floor tom, the Vérité comes much closer to putting across this feeling than the Utopia, which presents a thinner, albeit solid, low end picture. The Vérité’s edge on dynamics comes without sacrificing much low-end resolution. Bass guitars, for example, come across as squarer, with sharp string articulation, on the Utopia, while the Vérité offers a rounder rendering. This gives the Utopia a slight edge in apparent detail, but a less clear advantage upon closer listening. 


    The Atrium hits nearly as hard as the Vérité, but the balance is shifted slightly towards the midbass, in comparison with the Vérité, which has an almost (but not quite) planar-like linear subbass. Whether due to this slight midbass emphasis or the difference in driver material, the Atrium’s presentation is somewhat rounder than either the Vérité’s or Utopia’s. I suspect this sonic combination is, in part, why the Atrium has been likened to a “super HD650.” However, whereas I tend to assume the combination of rounded transients and mid-bass emphasis means that the low-end is soft or muddy (something that I think is true of the HD650, for all its virtues), that’s anything but the case when it comes to the Atrium.


    Instead, I’d venture to say that the Atrium’s bass may be subjectively the cleanest sounding of the three headphones. That conclusion cuts against my preconceived notions, but it’s what I’m hearing. Both the Utopia and Vérité emphasize the initial attack of the great David Hayes’s supple bassline. When he plays his clever 16th-note fills, the Utopia and Vérité accent the initial pluck. This is most extreme on the Utopia, which (being nitpicky) tends to be somewhat unsubtle and one-note in its low end delivery compared to the Vérité, which — by slightly deemphasizing the initial attack relatively to the Utopia — provides more sonic room for subsequent string noise and the decay of the note. The Atrium takes this a step further. It presents Hayes’s bass with incredibly subtlety and texture. The tradeoff is that it lacks some of the Vérité’s initial punch with each string pluck. Neither presentation is more “correct,” but were I to paint with a broad brush, I’d say that the Atrium’s presentation is the most matter-of-fact, whereas both the Vérité and, especially, the Utopia present a somewhat more hyped, “hi-fi” sound. Someone listening for pleasure might prefer the latter, whereas an audio professional might prefer the former. (Again, one can see where the HD650 comparison fits.)


    Returning to my previous comparison of the Vérité and Utopia using Morrison’s “I Have Finally Come to Realize”:


    Both the Utopia and Vérité open do an excellent job of reproducing microdynamics, the small gradations in volume that come from the slight differences in strength of each individual drum hit or string pluck. Part of the Vérité’s excellence in this area is that it’s every bit the Utopia’s equal in speed. The Vérité’s driver can start and stop on a dime, with each instrumental impact rendered precisely.


    Like the string articulation, however, the two headphones’ slightly different frequency responses emphasize different elements in microdynamics. As Tony Day’s drums come in on “Realise,” both the Utopia and Vérité allow the listener to easily feel the varying force of the individual snare hits and distinguish the snare’s skin from the wires. Sonically, though, the Vérité leans towards the skins, while the Utopia toward the wires. Similarly, both headphones convey the fine strokes of each cymbal hit, but the somewhat brighter Utopia produces more sizzle, which some listeners may prefer and others might find grating. 


    Re-listening to the Utopia and Vérité open, I stand by this accounting. Snare drums occupy a vast swatch of sonic range — including the crucial upper-mids and lower-treble, where the Utopia and Vérité most diverge — especially on relatively naturalistic, live-in-the-studio recordings like “Realize.” Being ultra-critical, one could expand on my description above by saying that the Vérité’s presentation of the snare is a bit boxy, while the Utopia’s is a bit tinny (though keep in mind that we’re talking about small differences on superb headphones). Adding the Atrium to the mix, it presents the snare with perhaps the best balance between the wires and the skin. However, it’s somewhat softer attacks also makes the snare sound a bit veiled, at least relative to the more aggressive Utopia and Vérité. Again, this is a small difference, but a real one. It’s also something that — to a much larger extent — is true about the HD650, underscoring the idea of the Atrium as an HD650 with its flaws greatly diminished and its strengths greatly enhanced.


    The above comparison also points to how tuning is about tradeoffs. Yes, the Atrium’s somewhat softer attack diminishes the snare’s initial impact, but it also leaves more room for subsequent sounds, thereby increasing the listener’s ability to discern those subtle microdynamics and textures.


    This characteristic extends to other instruments, too, with varying effects. For example, hi-hats and cymbals don’t quite have the same metallic bite through the Atrium as through either the Utopia or the Vérité open. But, again, the metals seem to have overall better texture through the Atrium. The same general observation applies to Morrison’s sax solo later in the track. But nowhere was this more obvious than on the Moog strings played by the legendary Bernie Kraus. Entering a little before the one-minute mark, Kraus’s Moog sounds the most realistic through the Atrium. How much of this is due to the Atrium’s superior microdynamics as opposed to its frequency response — which is arguably more neutral than the Vérité’s slight “W”-tuning and the Utopia’s upward tilt — is difficult to say.


    Continuing my previous observations:


    One of the highlights of “I Have Finally Come to Realise” is Morrison’s emotive, unguarded vocal. As Morrison delivers the “Oh sweet release…” line at the 1:22 mark, the Utopia give a more front-of-the-mouth sound, while Morrison’s vocal is more full-throated on the Vérité. This different shading perhaps owes to the Vérité’s flatter presentation in the 300 to 800Hz range. While both are superb headphones, the Vérité does a better job of conveying the emotion of Morrison’s voice and, later in the song, his sax — a quality I tend to associate with superior microdynamics. 


    The vocal presentation is perhaps the hardest to characterize when it comes to the Atrium. Its midrange presentation is simply gorgeous, and it projects a wonderfully deep soundstage (more on this later), which accentuates what sounds like stereo reverb on Morrison’s mono vocal. However, this is one characteristic where I think I prefer the Vérité’s slightly harder-edged transients. That said, I find the Atrium’s rendering of Morrison’s vocal to be more three-dimensional than the Utopia’s.


    Back to the Vérité review:


    Looking at the overall picture presented by each headphone, the soundstage is roughly as wide on the Utopia and the Vérité open. Neither presents the expansive soundstage of the HD800S, but both are the width I’d expect from a good open-back headphone. The front-to-back layering of instruments and voices is excellent on both sets of cans. However, the Utopia offers an ever-so-slightly deeper soundstage. This subtle difference in depth ties in to the greater “air” presented by the Utopia, as mentioned earlier. 


    The Vérité open is, to return to our epigraph, a cozier, more intimate headphone than the Utopia. With the Utopia, I feel like I’m in the studio (or at least the control room) with Morrison and the band. With the Vérité, I feel like Morrison and the band are in my room. The difference is subtle, but undeniable. The Vérité’s staging is closer to the listener, while the Utopia’s is slightly further away.


    The Atrium presents a soundstage that’s slightly wider than either the Vérité’s or the Utopia’s, and I’d slot its depth between the incredibly deep, almost u-shaped soundstage of the Vérité and the comparatively flat and up-front soundstage of the Utopia. The Atrium’s combination of width and depth leaves plenty of room for the reverb, which is more apparent than on the Vérité, though still less so than on the Utopia. Moreover, the decay of the reverb sounds very controlled and natural through the Atrium, compared to the Utopia, which seems to sustain the reverb a bit longer than is natural due to its bright upper-treble.


    Before undertaking more subjective comparisons, let’s bring in my measurements of the Atrium. These measurements were taken with my MiniDSP EARS fixture, which has been calibrated with a slightly modified version of Marv from SBAF’s compensation curve, where a perceptually flat frequency response is represented by a flat line.


    As noted above, few companies provide more measurements than ZMF. Their fixtures are much higher-end than the EARS, and Mehrbach shown that the area above 8 kHz measures very differently depending on the fixture used.


    All that said, let’s start with a straightforward measurement of the Atrium:


    EARS Measurement - Atrium.jpg



    Using the 80 dB mark as a rough guide, we a slightly elevated mid-bass, a slight emphasis on the 3 kHz region, a gradual downward slope from there to 8 kHz, then a narrow dip above that, and, finally, a slightly elevated upper-treble. Particularly given the documented difficulty of measuring the Atrium’s treble, I’m hesitant to put much stock in the particularities of what I’m seeing. For example, the Atrium doesn’t subjectively sound like it has an emphasis in the upper-midrange, which I associate with a fatiguing sound (the total opposite of the Atrium). However, it does sound to me like the Atrium has a good amount of upper-treble, given its excellent reproduction of reverb and “air.”


    Now, let’s add the HD6XX (Drop.com’s critically acclaimed version of the HD650) to the graph, in dark green:


    EARS Measurement - Atrium and HD6XX.jpg



    Well, I’d say it’s pretty obvious why the Atrium has drawn so many HD650 comparisons. That said, this is a perfect illustration of why characterizing a headphone based only on its frequency response is flawed. As great as the HD6XX is for the price, it’s not in the same league as the Atrium in terms of resolution. The HD6XX’s bass, for example, is much muddier than the Atrium’s clean and controlled bass. (While I’m hesitant to put much stock in the EARS’s absolute measurement of distortion, I think it works well for relative comparisons, and on that count it’s clear that the HD6XX has much higher distortion across the board, but especially in the bass, than the Atrium.) Moreover, the Atrium doesn’t really sound like it has less treble than the HD6XX, either. The HD6XX’s treble is certainly more grating than the Atrium’s. Maybe that has something to do with the differences in the 3 kHz to 6 kHz region, but I think it has much more to do with the fact that HD6XX’s treble is comparatively grainy and low-resolutions relative to the Atrium’s smooth, resolving high-end.


    Finally, let’s compare the Atrium (still light green) with the Vérité open (violent) and the Utopia (pink):


    EARS Measurement - Atrium, Verite, and Utopia - 1kHz.jpg



    Before commenting on these measurements, it’s worth pointing out how much where one decides to norm a comparative graph can impact interpretation. The graph above is normed to 1 kHz. But what happens if we take the same measurements and norm the graph to 250 Hz (which also happens to bring just about everything below 1 kHz into closer alignment):


    EARS Measurement - Atrium, Verite, and Utopia - 250Hz.jpg



    Neither of these is more “correct,” but the latter does a better job of characterizing how I hear the differences between these headphones. Specifically, the second iteration of the graph makes clear that the Utopia is the brightest of the three headphones. It also highlights the Vérité’s slight “W”-shaped tuning, including its emphasis in the 5-6 kHz “presence” region, which helps gives the Vérité its good transient attack, despite being a somewhat darker headphone. Finally, the Atrium’s frequency response resembles the Vérité’s in some ways and the Utopia’s in others. In my opinion, its overall balance is somewhat closer to the Utopia’s, except with a less-hyped treble. The most noticeable difference to me, subjectively, is that the Atrium has more upper-treble than the Vérité, which creates a somewhat “wetter” presentation relative to the “dry” Vérité, though (as noted above) the Atrium definitely doesn’t emphasize reverb as much as the Utopia does.


    Looking beyond the frequency response, the Atrium’s channel matching (like both the Vérité’s and the Utopia’s) is excellent. In terms of distortion, my measurements show that that the overall level is roughly the same between the Vérité and the Atrium, with both having slightly less distortion than the Utopia when tested at my approximately 85 dB frequency sweep level. The big difference, though, is that the Atrium’s distortion leans much more towards the second harmonic. Whereas third-order harmonics compete with the second-order ones, particularly in the bass, on both the Vérité and Utopia, the second harmonic dominates across-the-board (including the bass) on the Atrium. While I don’t want to read too much into such low-level differences, that might help explain why the Atrium’s bass sounds so smooth and clean.


    Finishing with another subjective comparison, I selected the 2011 24/96 remaster of an audiophile classic: “Bali Run” from Fourplay’s 1991 self-titled debut. (Yes, folks, we’re going smooth jazz here.) “Bali Run” is an incredibly dense and nuanced instrumental that mixes traditional jazz instrumentation with synthesizers.


    The echoing hammer strikes of Bob James’s (synthesized) piano have more bite through the Vérité and the Utopia than through the Atrium. This is a case where the Atrium’s somewhat softer attacks are a weakness, though the Utopia tends to go too far in the other direction. Meanwhile, Harvey Mason’s cymbal work has the most shimmer through the Utopia, with the Atrium coming in a close second thanks to its upper-treble. Keeping with David Hayes’s bass work on the Van Morrison test track, Nathan East’s busy bassline is easiest to follow on the Atrium. It presents it with the most texture and subtlty. The auxiliary percussion panned far left is best defined through Vérité, with the Atrium a close second and the Utopia a somewhat more distant third. Meanwhile, Harvey Mason’s floor tom hits (such as the ones near the 1:30 mark) have the best macro-dynamic slam through the Vérité, but the most nuance through the Atrium. One can hear the recoil of the tom’s skin after the hit through the Atrium, a subtlety that gets somewhat overwhelmed through the Vérité. The Utopia, for its part, lacks the slam of either ZMF headphone and underplays the body of the tom. Lee Ritenour’s guitar solo sounds too aggressive and treble-y through the Utopia. It’s most nuanced through the Atrium, but slightly muted, while the Vérité provides the best balance of bite and texture. Finally, the deeply buried synth that comes in around the 2:00 mark is most noticeable on Utopia, partly due to its high-end emphasis and shallower soundstage, which pulls the synth forward. In short, “Bali Run” underscores the differences observed with “I Have Finally Come to Realize” (and other test tracks not recounted in play-by-play here).


    The above, I think, accurately captures the Atrium in its stock form. However, as noted in the introduction, users can not only swap pads on the Atrium, but also the titanium mesh that covers the driver.


    The stock mesh is solid, but one can install a radial vented mesh (or remove the mesh completely). Buyers can request to have the vented mesh installed at the factory or can buy an extra mesh set (three pieces — one for each driver and an extra) for $20 from ZMF to be able to experiment with both kinds. Moving from the solid mesh to the vented mesh slightly elevates the treble, and removing it entirely elevates it even more. (Mehrbach, naturally, has a video explaining how to install the mesh.)


    Here are my measurements with the solid mesh (light green) and the perforated mesh (light blue):


    EARS Measurement - Atrium Mesh Comparison.jpg


    Especially considering that the headphones (obviously) had to be removed from the measurement fixture to swap the mesh, these are tiny differences.


    Using ZMF’s more resolving fixture, Mehrbach has posted his own measurements showing the difference between the stock (red) and the vented (dotted brown) mesh:





    As well as between the stock mesh (red) and no mesh (dotted green):





    Returning to both “I Have Finally Come to Realize” and “Bali Run” with the perforated mesh-clad Atrium, I found the differences to be subtle, but real. Overall, the treble is ever-so-slightly elevated, making the balance of the Atrium’s treble just a bit closer to that of the Utopia. Initial attacks are just a bit sharper, metals have more bite, and reverb is a bit louder. There’s a tradeoff here, of course. While this tweak doesn’t negate any of the textural or microdynamic advantages that the Atrium has over the Utopia (or the Vérité), it does somewhat lessen them in the process of restoring some edge to the treble. Personally, I prefer the solid mesh. But I could easily see some listeners preferring the vented mesh (or maybe even no mesh). There’s no “right” answer, and it’s simply a benefit to the buyer to have these (reversable) options.


    What about pads, which can be easily swapped by stretching the elastic band over the lip surrounding the Atrium’s cups?


    The stock Universe pads, covered in perforated lambskin, have a relatively tall and narrow ear opening, a maximum one-inch height, and a gentle downward fall from front to back. All of the above listening was conducted with these stock pads, which are included with every pair of Atrium headphones. But buyers also get their choice of one other set of pads, and Mehrbach included a bevy of different pads with the review Atrium.


    The Vérité Be2 pads are ZMF’s flattest pad, with almost uniform height from front to back and an ear opening that’s slightly shorter, but also slightly wider, than the stock Universe pads (thereby creating a rounder opening). In their perforated lambskin covering, the Be2 pads provided a listening experience that was slightly different from, but overall the sonic equal to, the stock pads. Because the Be2 pads bring the driver slightly closer to the ear and change the driver’s angle, they sacrifice some soundstage width. Otherwise, however, their primary effect seems to be making the Atrium sound a bit brighter and, arguably, even more neutral and reference-ready without the tradeoffs that I found switching from the solid to the perforated mesh. (If I were someone who wanted more treble from the stock Atrium, I’d switch to the lambskin Be2 pads before trying the vented mesh.)


    While I don’t put much stock in the EARS’s measurements of pad differences, here’s what the Atrium looks like with the stock pads (light green) and the lambskin perforated Be2 pads (yellow):



    EARS Measurement - Atrium - Universe vs Be2 Lamb Perf.jpg




    I also tried the perforated suede version of the Be2 pads. They created a noticeably narrower soundstage, but also provided a little more immediacy and intimacy. The suede seems to sacrifice some low-end resolution while also taming the treble. Overall, they create a relaxing, pleasurably listen with roughly the same tonal balance, but slightly less detail, than the perforated lambskin Be2.


    For completeness’s sake, here’s how the lambskin perforated Be2 pads (yellow) compare with their suede perforated counterpart (red) according to the EARS:



    EARS Measurement - Atrium - Be2 Lamb Perf vs Be2 Suede Perf.jpg



    The Auteur pads have a slightly larger ear opening than the stock Universe pads and roughly the same maximum height, but more of an angle from front-to-back. Sampling them in their perforated lambskin covering, these were my least favorite option. That said, the effect was subtle, and I’m sure some listeners might rate the Auteur their favorite pad option (especially given how much individual ear shapes impact pad preference). To my ears, though, the bass seemed to lose a bit of focus with the Auteur pads. On the other hand, the Auteur pad did raise the treble, and could appeal to listeners who want a more aggressive high end. Even though my EARS measurements don’t support this, subjectively the Auteur seemed to change the frequency balance in the treble more than any other pads. With the perforated lambskin Auteur pads, the Atrium still sounds fantastic in an absolute sense, but I think it loses some of what makes it special. That said, this what the EARS fixture finds comparing the Atrium with the stock pads (light green) and the Auteur perforated lambskin pads (grey):



    EARS Measurement - Atrium - Universe vs Autuer Perf.jpg




    Where does all this leave us, in terms of the ultimate verdict on the Atrium? On one hand, there’re my own personal tastes. On the other, there’s what I think will agree best with most listeners. I want to evaluate the Atrium from both perspectives.


    As noted at the beginning of this review, the Vérité open receives something like 2/3rds of my headphone listening time. The Atrium surely is going to cut into that fraction, but I’m not so sure that it will overtake the Vérité. As noted above, the Vérité shades towards the famous Japanese hi-fi “W”-shaped tuning. I find that this type of tuning can help create a deeper, more speaker-like soundstage. It can also help throw certain details into sharp relief by somewhat reducing frequencies that tend to sound muddy on headphones. Moreover, the Vérité open’s slightly dark tuning helps avoid fatigue on long listening sessions. Combined with its stupendous dynamic impact, speed, and marvelous detail retrieval, those characteristics the Vérité a fun, but still audiophile-worthy, listen.


    However, when it comes time to do critical listening to albums for my TBVO columns, I balance my Vérité listening with the Utopia, the HD6XX, and (of course) speakers. The Utopia’s bright frequency response is superb at revealing any minor flaw in a mastering. However, that also means that listening to the Utopia alone would lead me to wrongly favor darker masterings. Moreover, the Utopia’s somewhat flat soundstage can understate depth differences between one-dimensional masterings and their more lifelike competitors. Meanwhile, I reach for the HD6XX largely for its frequency balance, but I never expect it to ferret out the small details that often make the difference between a good and a great mastering — something that both the Vérité and Utopia can do.


    That’s where the Atrium will come into play in my personal use. While I always try to use a variety of transducers when evaluating masterings, I’m confident that the Atrium — with the solid mesh and either the perforated lambskin Universe pads or the perforated lambskin Be2 pads — will now be my first choice for that task. The Atrium is the most truly neutral headphone out of the Vérité, the Utopia, and the HD6XX. Indeed, I suspect it could easily make inroads with audio engineers were ZMF to market to that crowd.


    cash@2x.pngDue to its neutral frequency response, excellent soundstage (width and depth), superb detail retrieval, and class-leading microdynamics, I’m convinced that the Atrium might be not just the top ZMF headphone for most audiophiles, but also the top headphone, period, for most audiophiles. The ability to alter the Atrium’s tuning to taste by swapping pads and mesh only strengthens the case for the Atrium. Add in ZMF’s build quality, accessories, and warranty, and the Atrium sets the bar for all other “summit-fi” headphones.


    Listeners looking for a slightly more high-contrast, macrodynamic listen might prefer the Vérité, while those who favor bright-leaning cans might lean towards the Utopia (or, on a budget, the ATH-ADX5000).


    But for most audiophiles — especially those who consider the HD650’s tuning to be neutral — the Atrium is the top option on the headphone market today. Period.


    * What makes these characteristics so interesting, too, is that I could swear that the Vérité’s driver is “faster” than the Atrium’s. Indeed, one would expect that a Beryllium-coated driver would be faster than a biodynamic driver, and I do think I still hear this slight difference in transient attack. But, generally, I tend to associate speed with blacker background and better imaging, since a speedier driver (all else equal) should lead to faster decays. However, it seems that ZMF’s new damping system allows the Atrium to upend these assumptions.



    Editor's Note: Josh is far to modest to put in a plug for his new Club TBVO, but I'm happy to do it, without his approval. Fans of his writing must check it out here.





    About the Author

    jm.pngJosh Mound has been an audiophile since age 14, when his father played Spirit's "Natures Way" through his Boston Acoustics floorstanders and told Josh to listen closely. Since then, Josh has listened to lots of music, owned lots of gear, and done lots of book learnin'. He's written about music for publications like Filter and Under the Radar and about politics for publications like New Republic, Jacobin, and Dissent. Josh is currently a postdoctoral fellow at the University of Virginia, where he teaches classes on modern U.S. politics and the history of popular music. He lives in Charlottesville, Virginia, with his wife and two cats.

    EARS Measurement - Atrium - Universe vs Be2 Lamb Perf.jpg

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    Hi @JoshM thanks so much for the detailed review. This is another great one. Your comments below are really something. Seriously, the Atrium must be on another level to be worthy of these statements. 


    After reading this, it's easy to see why you told me offline, that the Atrium should definitely be on the CASH List. 



    "I think the complexities of headphone creation (and measurement) make obsession with perfect “neutrality” a fool’s errand. But that hasn’t stopped headphone fanatics weaned on the HD650 from longing for a “super HD650” — a pair of headphones that comes close to the HD650’s frequency response but adds a cleaner and more impactful bass, subtracts some grain from the treble, and elevates the HD650’s detail retrieval."


    "Well, with the ZMF Atrium, the “super HD650” is here."


    "But for most audiophiles — especially those who consider the HD650’s tuning to be neutral — the Atrium is the top option on the headphone market today. Period."

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    I am curious how you would compare the Atrium to Meze Empyrean? I never found the Focal Utopia's to be convincing when auditioning, sounded synthesized vs

    natural for tone color. The Empyreans were an easy headphone to forget focusing on auditioning and lapse into enjoying for tonal nuance.

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    6 hours ago, The Computer Audiophile said:

    Hi @JoshM thanks so much for the detailed review. This is another great one. Your comments below are really something. Seriously, the Atrium must be on another level to be worthy of these statements. 


    After reading this, it's easy to see why you told me offline, that the Atrium should definitely be on the CASH List. 



    "I think the complexities of headphone creation (and measurement) make obsession with perfect “neutrality” a fool’s errand. But that hasn’t stopped headphone fanatics weaned on the HD650 from longing for a “super HD650” — a pair of headphones that comes close to the HD650’s frequency response but adds a cleaner and more impactful bass, subtracts some grain from the treble, and elevates the HD650’s detail retrieval."


    "Well, with the ZMF Atrium, the “super HD650” is here."


    "But for most audiophiles — especially those who consider the HD650’s tuning to be neutral — the Atrium is the top option on the headphone market today. Period."


    Thanks, Chris. As you can tell from the review, I'm both blown away by the Atrium and still personally a bit partial to the Vérité. There's little question in my mind that the Atrium are the more "neutral" of the two and the ones that I are a safe recommendation for most audiophiles. (Sometimes I think reviewers conflate their personal tastes with recommendations for others.) That's also what makes the Atrium a great tool for my TBVOs!

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    6 hours ago, davide256 said:

    I am curious how you would compare the Atrium to Meze Empyrean? I never found the Focal Utopia's to be convincing when auditioning, sounded synthesized vs

    natural for tone color. The Empyreans were an easy headphone to forget focusing on auditioning and lapse into enjoying for tonal nuance.


    I haven't had the Empyrean at home for a proper audition. I did, however, get to listen to them for an hour or so in a quiet location with a Mytek Brooklyn and music of my own choosing from Qobuz. (Based on the specs and other reviews, one would think the Brooklyn's headamp would be enough to drive the Empyrean well, but I've definitely encountered situations where specs don't seem to match subjective power.)


    With that proviso, I strongly prefer the Atrium to the Empyrean. When I auditioned the Empyrean, I also listened to the Focal Stellia and Rosson RAD-0. The Empyrean were my least favorite of the three. I found the Empyrean's bass to be a bit bloated and flabby, and thought the mids seemed a little scooped. I've definitely encountered situations where better amplification cleaned up the bass, so it's possible that characteristic of the Empyrean would've been better through a different amplifier. However, the RAD-0 also requires a lot of power, and I thought they sounded much better through the Brooklyn than the Empyrean did.

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    I just updated this review to replace the graph where I accidentally obscured part of the frequency response with REW's tools dropdown. I also added info on the DAC and headamp used for the critical listening. I'd included that in a previous draft, but accidentally excised it from the final draft.

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    Josh your headphones reviews are the most detailed and well written reviews out there.  I bought the Verite Open thanks in big part to your review and I am really happy with them. I am sure people looking for a super 650, finally will have their prayers answered. Great job 

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    Interested in the Atrium. I am currently a HD800s owner. So really curious how Atrium stack up against HD800s. Any thoughts?

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    On 1/2/2023 at 9:37 AM, micatske said:

    Interested in the Atrium. I am currently a HD800s owner. So really curious how Atrium stack up against HD800s. Any thoughts?


    IMHO, the Atrium is in another league from the HD800S, which I owned previously. You can probably get a sense of how the HD800S stacks up against the Atrium, at least in a transitive sense, from my ATH-ADX5000 review, where I used the HD800S and (like the Atrium review) the Utopia as comps.

    The one area where the HD800S might exceed the Atrium is soundstage width, but even that is probably less significant with the Atrium than with many other competitors, since the angle of the Atrium's driver creates more perceived width than the driver's actual distance from the ears might create otherwise.


    The only other potential difference is that -- depending on your individual HD800S -- the Atrium might have less "air." I say "potential," since the review HD800S I got was much brighter (subjectively and in measurements) than the unit I bought for myself. However, I think the quality of the Atrium's treble -- in terms of nuance and microdetail -- will be better, even if it's overt treble detail is less striking than a bright-leaning HD800S.

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    I had the RAD-0 and found it heavy and awkward to wear.  What is the “head feel” of the Atrium?  Clamping, balance, weight?



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    On 1/5/2023 at 9:46 AM, bobfa said:

    I had the RAD-0 and found it heavy and awkward to wear.  What is the “head feel” of the Atrium?  Clamping, balance, weight?




    The Atrium is over 100g lighter than the RAD-0. I also think the new ZMF headband does a better job of distributing weight than the RAD-0's. 

    In terms of clamping, the clamping force is lighter with the Atrium. However, the Atrium's spring steel headband can be adjusted to increase or decrease the claiming force, as well as the shape of the arch.

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