SOLID AIR! The ZMF Atrium Closed Back Headphone
BACKGROUND AND FOREGROUND:
JM (John Martyn): Hey, SLC thank you for bringing me out of my deep dark place in order to ask you some questions out of my curiosity about the new ZMF Atrium Closed Headphone. I know you have listened to my music obsessively and thank you for appreciating my art. Please start out by giving us a little
background and
foreground before you start this review.
SLC: Can do John. It is a pleasure to be around you! Please say hello to Beverley from me. I know you are still in contact.
The Atrium Closed I am reviewing is a demo unit provided on loan to me by ZMF. It is the stained Cherry version of the stock wood and has gold rods. The change in shimmer as you look from one side of the face to the other is mesmerizing. This one has a lot of hours on it as a demo and was at Canjam. I have owned every ZMF headphone and what I can say is that they are, as with each ZMF HP, unique in how they present the notes to my cerebral space. I have not heard the Eikon for 5 years but some Eikon images are brought out as well as Auteur feelings of joy. I can hear that lineage in the Atrium Closed.
Another winner for Zach and Bev the owners of ZMF Headphones! Beautiful stuff. I have obsessed on certain HPs and certain audio companies. Such as Vision Ears, Sennheiser, and Noble Audio. Each for different reasons. ZMF is among the companies I admire. I admire ZMF for what it is seeking to do and how it represents itself and how it takes care of its clients. It is obvious that Zach is passionate about music and how notes are conveyed. That comes across in each one of his Headphones.
Each ZMF HP brings something different to the table. It is not at all about one being better than the other. It is about personal preferences. That is how good each one is.
For reviews, as of late, I use a fictitious discombobulated interviewer that is the unique interviewer for that audio company. John Martyn is one of my musical heroes. In honor of JM I will bring him back to life and he will be the ZMF fictitious interviewer from now on. A discombobulated genius he was! The title for my review will be “Solid Air” which is the title of one of his songs and for me the sound of the Atrium closed represents solid air. Each question from JM will include a quote from one of his songs at the end of my response to his question.
The goal of my review is to be as informative as possible and make it entertaining for my sanity/pleasure and hopefully for your pleasure. I usually include in the review an interview with the creator of the audio product. JM did ask Zach a few questions out of curiosity for this review. They ran into each other recently at a pub near Zach’s house. John can be found in many pubs around the world!
Along with my impressions of the AC, I will also dive into comparisons with other HPs. This will include a close cousin and a sister of AC: the Verite Closed and the Atrium Open. That will allow the reader that has heard those get a cognitive and maybe visceral feeling of what the AC is like. I will throw in a comparison with the Dan Clark Audio Stealth for those that have heard the Stealth. If the reader has not heard any of the comparison HPs, at least it will give you an idea of differences between them and possible personal preference you might have.
“I’m going home hey, hey hey, over the hill”. JM
SLANT OF FACE:
SLC: John, the evolution of your music is a pleasure to listen to. From your albums with your wife at the time, Beverley, up to Grace & Danger. I thank you.
JM: Well, thank you SLC but I am offended with “up to Grace & Danger.” That was 1979. I lived longer than that. Anyway, please tell me about the
slant of the face of the Atrium Closed. That is all you seem to talk about late at night.
SLC: The slant. So sexy. Only pictures can convey the slant and how the AC slant compares to the Verite Closed slant. Oh the slant.
Here are a couple pictures of the face angle/slant of the AC compared to the VC face slant.
First picture is with VC on top as she prefers to be. Sorry about the intimate mini XLR 4 pin female housing shots.
The second picture shows the slant well with the VC Leopard wood spooning on our left.
“If I can’t be a peaceful man, I will be who I can” JM
SOURCES AND CHAIN:
SLC: John, the 80’s were not nice to the late 60s and 70s musicians. Synthesized drums and adding your drinking buddy Phil Collins into the mix for Grace and Danger says it all.
JM: Those were my sources at the time and the direction recorded music was going at the time and I was starting to go to the very dark side. On the topic of
sources, what chain did you use for this review?
SLC: All my impressions will be with these setups: Khozmo passive pre + Ferrum OOR/Hypsos + Yggdrasil OG and Holo May KTE + Holo Bliss KTE.
I do have the Jotunheim 2 and Bifrost 2/64 at work but I was not able get a chance to listen to the Atrium Closed on that setup. Darn work always got in the way

Something like Bifrost with Jot or any quality tube amp is all that anyone “needs” for ZMF HPs. The rest is audio illness overkill of which I am very guilty of and most of you reading this are guilty of or will be guilty of. Is all part of the hobby/addiction. That said ZMF HPs scale up well with quality amp power and of course react well to quality tube amps. The Caldera was the only ZMF HP I have owned that did not change as much with each setup. That is most likely because it is a planar HP versus with a dynamic driver in all other current ZMF Headphones. The Caldera does not require as much massive power as for example the Susvara or Stealth or Expanse. The Caldera played happy with everything I threw at it. Obviously with a non powerful DAP or dongle it was fine and enjoyable but did not shine as much as with a powerful transportable DAP or a quality 2ch or desktop amp/dac setup. That did make a big difference with the Caldera.
I would like to start my impressions by mentioning the sub bass of the AC. So visceral. I can feel it. Super textured. But does not take anything away from the rest of the signature. I am using just the leather pads for now. I will compare the leather and suede pads at some point. I have always ended up going back to stock pads over time on all my ZMF cans. I think Zach chooses the stock pad extremely well. I also just prefer the feel of leather on my head compared to suede. Just a personal preference though.
The sub bass stays away when not called for but when it is called for it shines. This is key so that the bass does not overwhelm when not needed. I am really into sub bass and the AC does it for me. It is like the HD600 sub bass vs the HD650 mid bass focus. Or the Eikon sub bass slant vs. the Aeolus mid bass focus. The AC tops all of those in texture and for lack of better words it has a next level maturity going on in the sub bass. It is not just a fun bass that gets boring after a bit. It is mature and draws me in to understand it more even after an extended 5 course date together at a French restaurant. That says a lot
“Now please won’t you, please won’t you bear it in mind for me” JM
TREBLE:
JM: Now that is all off our chest can you talk a bit about where I like to start and that is the
top end?
SLC: Your favorite area JM! How is the Atrium closed on top?
It is a marvel what Zach has done in that I hear the top end as very present but…… I have written numerous times in the past that I have not heard a treble I did not like. In the case with the AC, I hear the treble as very present but in a good way. I usually do not focus on the treble. It is always part of the evening or morning pleasure but not a focus of the foreplay nor post-play. With AC I spend time focusing on the treble and hear the treble in a different way. I can feel the sticks hit the cymbal with texture. I can picture the actual softness or hardness at which the cymbals are contacted. “Music Delivery / Percussion” by Andrew Cyrille is a great album to discover and feel the texture of the treble with the AC. Rather impressive.
I am not hearing the treble as rolled off which adds to the feeling of staging for a closed back HP. I am hearing the presence of the treble but with no fatigue. The treble plays into a theme of the sound of the AC. The theme of resolution, detail retrieval and clarity but with musicality and non fatiguing smoothness.
I know I have had HPs with great top ends but this is the first one that has me looking up top as much as down low!
“Take a little look from the outside if you can” JM
MIDS:
JM: And your favorite area SLC, the
mid section?
SLC: Yes, those mids. What is life without them!
Mids are really important to me and play an important role in the overall signature of an IEM or HP that I look forward to listening to. I cannot handle when too much is focused down low or up top. The Atrium Closed has the sub bass that is a star and the treble that draws you in. But how is the core of the AC?
I am hearing mid-range of the AC as not forward nor recessed. The mids are right where they need to be. That had to be hard to achieve with such good sub bass and treble. I do hear female voices a little bit forward compared to male voices. I hear a tiny bump in the upper mids compared to the lower mids. My guess is that is because of the treble being well balanced from upper and lower treble as compared to the bass that has a sub bass slant. This sub bass slant probably takes a little away from the lower mids. Just a guess from what I hear in my head.
Nothing is scooped out of the core nor raised to a level of easy fatigue. The AC has smooth well textured mids that ask for your attention but do not demand it. I have been listening to trio jazz all morning with Sax being the main instrument (recent Charles Lloyd). I am extremely impressed with the amount of “realness” and “liveness” in the sax notes. The tonality is so good and with feeling/texture. The excellent texture of the notes will be a theme throughout this review.
As I mentioned before the resolution and clarity are still excellent despite the smoothness. It is not an overly warm smoothness but more of a detailed and textured smoothness. Great combo in my opinion. The natural decay of the notes do not add much color at all. They add a lot to the enjoyment.
“This is the beginning of forever” JM
SIGNATURE OVERALL:
JM: According to you, my first 10 albums were the only good ones and those 10 defined my overall signature, can you talk about the
overall signature of the AC?
SLC: 10 albums is 7 more than most excellent musicians ever create. 1967 to 1976 is an amazing run and you did that all while the demons were at the door.
The signature of the AC is a pleasure to discover. I do not look at frequency graphs. Due to a lack of those skills or mainly because I care about the frequency graph in my warped mind. The frequency graph in my head has the AC going far to the left and far to the right for a closed back HP. That could cause issues with not being able to touch the notes in the middle (the Oriolus Traillii IEM for example). This is not the case with the AC. I hear an amazing correct presence of sub bass on one end and very correct and present upper and lower treble. The magic sauce in my opinion is that Zach put in enough mid range so that the Left and Right ends of the stage do not dominate. No dominatrix with the AC.
Most of instruments and vocals in songs are in the mid range. The mids have to shine otherwise you have a one trick pony. The mids of all ZMF headphones in my opinion are always enjoyable whether it is a thicker warm HP or a more analytical ZMF HP. For me the vocals and instruments like the trumpet need to be what I hear well and with feeling. The AC does not disappoint with that. Some HPs are more about the bigger picture and the intellectual act of focusing on each part of the signature is not what it is about. With the AC it is super easy to focus on each part of the signature and it is an intellectual joy to do so. But it all comes together to make the overall experience smooth and pleasurable. That to me is what makes the AC special. It is smooth with detail and clarity but somehow all those separate parts come together as one. I attribute that to the world class texture of this headphone. The Atrium closed does not go so far with the detail and clarity to become a clinical HP. The AC still has feeling in its detailed notes. The ZMF house feeling is still there.
Speaking of feelings, an AC revelation hit me last night. The AC is not about just smoothness, not just about clarity and detail, the biggest win that is now hitting me is the actual feeling behind the notes I am hearing. This texture as I have already mentioned a few times. I hear the saxophone, the trumpet, the drums, the guitar, the bass, the vocals etc. with feeling. I can feel the notes of the instrument. That is coming to the forefront after many hours of focus time with AC. She has met my parents and now we are getting our first apartment together.
“Some people got a glass eye, some people got a window to watch”. JM
TIMBRE:
JM: Yes, the demons did get me in the long run but
the notes were always in my head. Tell me about the Atrium Closed notes Mr. SLC?
SLC: I know you love chocolate John so let me use chocolate as an analogy. And do you remember that time John at the chocolate bar in Dublin?
I describe notes as somewhere on the chocolate scale. For example the Verite closed to me is more about milk chocolate notes. A little thicker and a little longer decay. A smooth impactful taste. The notes of the AC are more in the dark chocolate range. They are more clear, and more fine with less decay/reverb but with a truckload of feeling in each note. Some HPs have thicker notes and the presentation is more about the big picture and then you have to look hard to figure out the different parts.
The AC has the fineness of dark chocolate. Each part is easier to decipher. Each flavor hits me first with amazing texture. Whether it be a hint of almond or caramel or a coffee flavor. But those distinct flavors can be put together if I want into the overall flavor of the dark chocolate. The trick of understanding dark chocolate is letting each flavor that hits the palate be experienced. It is about the individual parts first which make the whole of it a joy. The AC is like that with an added bonus of still being smooth and textured. Each very distinct flavor goes into my being and combines into one as I want and when I want. The AC notes are like that. The individual to the whole vs. the whole to the individual. The Gestalt of the AC is really good: Gestalt as in “the human brain will attempt to simplify and organize complex images or designs that consist of many elements, by subconsciously arranging the parts into an organized system that creates a whole, rather than just a series of disparate elements.” I referenced Gestalt in a review I did of the Vision Ears EXT. That was about the whole first and then the parts second. The AC is about the individual parts that lead into a wonderful whole.
How the notes are presented and the signature of the AC is what creates this beautiful Gestalt.
“You’ve been painting it blue, and you’ve been looking through solid air”. JM
COMPARISON, VERITE CLOSED:
JM: I know one of your favorite test tracks is Cousin Dupree by Steely Dan. Sick song and sick name for a group by the way. Can you tell me about the Cousin of Atrium Closed,
the Verite Closed?
SLC: yes, it is an odd song but very well recorded as were your 4th to 8th albums.
What a compliment to each other! I just mentioned the whole Gestalt thing of the individual parts into a whole and vice versa. Well the VC and AC really are Ying and Yang. I know the VC well. I have owned it in three different woods. The current version being Leopardwood. VC is about the whole first. The music is presented first as something you can sit back and enjoy as one. In an impactful way but as one first. The AC has the individual parts first that combine into the overall music in the brain. With VC you go to the music/notes or not. With the AC the notes/music come to you. You can decide to lean back and relax and enjoy the overall music or not. VC is to AC as HD650 is to HD600. VC is to AC as DCA Expanse is to DCA Stealth. VC is to AC as Atticus is to Eikon. VC is to AC as Aeolus is to Auteur.
Yes, VC has impactful notes but the notes are milk chocolate as I mentioned before. They are thicker and the decay is longer. The AC is the dark chocolate. The notes with the AC have a quicker decay for me but still with a lot of texture/feeling. But the flavor of both last long whether milk or dark. Just a different flavor.
When I compare the same song with AC then VC and back and forth the first thing I notice is how the bass in presented. Strong sub bass with the AC. Very strong when called for. The VC presents the same bass on the same song as more mid bass focused. The second thing I notice is that the timbre of female vocals are different. Not better or worse but different. It takes about a minute to adjust. The tonality of the instruments are similar.
The impact of the thicker notes of the VC also comes out right away when I go back and forth. The AC presents the same notes as more laid back and more lean. Lean as in a smoother way with the main feature being as I mentioned before the feeling of each note of the AC is outstanding.
These two closed back HPs do compliment each other well.
“She walked to the water and came back looking good and feeling fine”. JM
COMPARISON, ATRIUM OPEN:
JM: This allows me to transition to the sister of the Atrium Closed. That would be of course
the Atrium Open.
SLC: “You're just like a sweet and simple sister to me” from May You Never. I love your lyrics John!
The timbre/tonality comes across as very similar which of course makes sense. The AO comes across as more relaxed even though I would not consider it a warm HP. To me it is a relaxed HP. The AC notes are more in front of me and intimate in comparison and to the left/right and back and fore notes of the AO. The AO notes are around me but are more chill about it. AO is more of a longer session sound vs. the more present notes of the AC. AC is still for longer sessions just not as long as AC. AO is there all around you and you become one with it. The AC due to the added intimacy always keeps you a little on your toes. Ready for a little lovin’.
The staging of the AO is wider and higher which is to be expected with an open back HP. They both have a staging that is around the head. AC has a more intimate of stage as mentioned before but pulls off a wide Left to Right stage due to the added sub bass (wow is it good) and a very tiny bit of added sparkle on top compared to the AO.
They share timbre but depart from there. Wonderfully but also financially annoying, the AO and AC can both exist in ones staple of HPs just like the AC and VC can. If you really like the timbre of the Atrium then the AC will provide added isolation of course, added intimacy, added fun and added sub bass. AO will add space, an even more balanced signature, and a limitless lack of fatigue for very long sessions.
The AO likes to hang out with you and chill. The AC is a pleasure to be with but does have more of the “hello, I am here for some lovin’” going on.
“Life, go easy on me, love, don’t pass me by”. JM
PADS AND IMPEDANCE:
JM: Pads and Impedance! Our mantra when we would go out in the old days. Talk about them SLC!
SLC: Yes, a little P & I! Got us far late at night.
I will compare the Caldera slim leather pads (stock for Atrium Closed) with the Caldera suede pads. As I mentioned at the start of this review, with each ZMF headphone I have used, I end up pad rolling and then sticking with the stock leather pad. There are three reasons for that. One is that I think Zach uses the stock pad for a reason. It seems to be the one he prefers for the sound he wants/likes. Second, I prefer the feel of leather over suede. Just a personal preference there. And third it does end up being the sound signature I prefer.
Pad rolling with ZMF HPS is like cable rolling with IEMs but pads are lot less expensive than IEM cables. Each pad adds a different flavor to the existing signature.
That said what do the suede pads do to the Atrium closed sound that I am so used to now? Overall what I hear is that the suede adds an added touch of smoothness. If you find the signature of the AC needs to be smoothed out more then try the suede pads. It feels like a smoothness filter was put on them when using the suede pads. Everything is toned down a bit. Nothing is lost just toned down. It is a great option to be able to tweak the sound.
Short aside on Low and High impedance with the Holo Bliss KTE Amplifier. With an IEM the difference is drastic. The Hi-Z setting is not a friend of the EE Odin for example. But with Lo-Z setting things sound like they should. With the AC HP I notice a smoothing out even further with Lo-Z. Too smooth for me. I prefer the Hi-Z setting. This might be because I have spent many hours on Hi-Z with AC already. The detail and bass are better with Hi-Z. The texture is so much better on Hi-Z.
COMPARISON, DCA STEALTH:
JM: My first 10 albums according to you (I did other great albums you know) were staples. A current closed back staple according to a lot of people, is the
Dan Clark Audio Stealth. Compare it to the AC please.
SLC: Remember John, 10 albums is 10 more than most and 7 more than other great musicians.
With the Stealth there is a lighter contact of the notes. The notes are a little further away from me. The Stealth takes a few minutes to adjust to before the music sounds “right”. This happens with me with most planar HPs. There is a slight mind adjustment that needs to happen. Then all is good. The Stealth is a lot harder to drive than the AC.
The two share a lot in their signature. My theory is in order to add staging both have an added sub bass slant and an added tiny sparkle on top. They both have excellent clarity and detail. Both have notes that are not milk chocolate in nature but are of the dark chocolate variety i.e excellent texture.
As I stated already the Stealth has the music around me but a little further away. The AC notes are closer to me in my head and more intimate.
The Stealth is considered by some to be the best closed back headphone in the world. The fact that the AC competes extremely well with it says a lot.
When I go back and forth between the two the planar vs. DD difference becomes obvious. Again they share a lot with their dark chocolate signature but a quality DD has that “analogue” halo around the notes compared to a more “clinical” presence around the planar notes. Neither is better than the other. Just a different flavor of a very similar dark chocolate.
Interview with Zach Mehrbach, the creator of ZMF Headphones:
JM: Despite their differences in signature, the tonality of the AO and AC are very similar in a wonderful way. That said, the Atrium Open uses an Acoustic Titan Mesh. How did this come about with the Atrium Open? And how did it come about not being used with the Atrium Closed?
ZM: The titan mesh we custom cut to get what I deem "the right" amount of treble. There was quite a bit of back and forth in the Atrium open to arrive at the spot where the peaks are in the most agree-able place for the greatest amount of people. With the Atrium Closed I did have it on for quite a while, but then when I switched to tuning with the Caldera pads enough of the front energy was dissipated slowly through the outer perforations to enable me to get rid of the titan mesh.
It will be interesting to see as I move forward if I end up needing the titan mesh on any Caldera pad tuned headphones, but overall the titan mesh is used as a non destructive to "other" frequencies mesh to enable a custom tuning to the users preference for treble/above 3 KHZ or so frequencies. I tune all of them to my taste but we offer different meshes on the site for different tastes. A number of users use the Atrium with a solid mesh and some with no mesh on them.
JM: Zach, I cannot get over the slant of the face of the AC. I keep looking at it and touching it. I feel like Narcissus in front of the pool. How did the slant come about and why is it a different slant compared to the Verite Closed? Were you watching French New Wave movies especially by Godard and you became inspired to add a slant with a sexy curve to it?
ZM: Ha I appreciate the auteur/new wave reference! Really I set out to make sure it looked as different as possible from the Verite Closed as I could make it while retaining the internal characteristics that helped make the Verite sound the way it did. I knew that with my closed designs I don't like to angle driver (not yet) due to it causing unpredictable back wave and response characteristics. So angling the cup to a greater extent made sense to get the right kind of decay that worked with the Atrium damping system and dissipation of energy/air flow.
Aside from that - I wanted more weird things to be included, like an inlet or "gulley" of sorts. But it turned out that was really really hard to sand and would've been inconsistent visually.
JM: I had a hard time keeping the passion for creating new art going. Especially as the demons visited me more often. How do you take a passion and turn it into a profession and still keep the passion?
ZM: I think there's such a gamut/divide between what it takes to run a good business, and make a good headphone. If anything running ZMF as a good business to keep our staff employed and be a good employer, has just made my appreciation for making and enjoying headphones even greater. I typically spend my "free" time working on the headphones when it's not business hours as a way to "wind down" from all the frustrating ins and outs of the business part of ZMF. I just love that part of "creating" and fortunately have been able to keep it separate from the rest of it. It's been more of a struggle as ZMF has gotten a little bigger, but I plan on trying to keep it that way!
JM: Thank you Zach for taking the time to allow me to interview you. I am glad I ran into you at your nearby pub!!
CONCLUSION:
JM: OK, SLC our time has come to part, I hope to interview you again in the not so distant future. And yes, 10 classics was a lot of albums. Can you give the reader a
final note before we part ways?
SLC: I will see you in the future JM. You will be back. Thank you JM for making the trip to the States for this review. I appreciate your insightful questions and I have enjoyed many hours with your music!
ZMF has done it again. A work of art both visually and aurally! The lineage of the Eikon/Auteur is there but for me it is taken to another level of texture of the notes and overall presence around my head. It seems very hard to keep the stage open and the reverb away in a closed back headphone. ZMF does amazing open back HPs and somehow creates masterpieces with closed back headphones. The sibling of the Atrium closed, the Atrium Open, is a wonderful headphone in its own right. The Atrium closed shares the same timbre but the overall presentation is its own thing and for sure should be experienced by anyone that can experience it.
I tip my hat to ZMF!

The Caldera is simply amazing. It sounds like a planar if you're ok with that. The jump in resolution isn't going to blow your mind stepping up to the Caldera, but it in some ways is like going between a LCD with very realistic color representation and a super rich OLED. I can't get enough of either of them.