Introduction to the ZMF Caldera Review
Some things take time to happen. You can’t have everything in life, can you? This has been my story with ZMF for a few years, when I was actively trying to get their headphones to review here at Ear Fidelity.
Good things come for those who wait, you could say. It’s finally happening, as you’re reading the ZMF Caldera Open review literally right now. Why the hustle, though, you might ask?
You see, I like to consider myself more of an old-school headphone enthusiast. Well, I’m not talking like the 80s or 90s, but the 2000s and 2010s definitely. The market around the year 2010 was waaaaaaaaay different from what it is now…it was more unique, alive, and had a lot more personality.
What does that have in common with the Caldera, though? Well, this is the headphone that reminds me of the good old days, you could say. It’s not about cutting-edge trademarked technologies, a hyper-neutral sound signature, and a bland design that’s forgettable.
This is definitely an artisan-level product, made for those who value things that are different, special, hand-made, and have a soul. I’ll try to explain why, so feel free to continue reading.
Packaging
First of all, we’re going to cover the unboxing experience. Why? You’re paying 3.5k USD for a pair of headphones, surely you want something fancy, don’t you?
“Fancy” might not be the best word to use here, but damn, this is QUALITY. The Caldera comes in a big pelican-style case that screams protection all over it. Sturdy, quite compact, and probably could survive a massive drop to the concrete. Why would you do that? Not my business, but hey…maybe good to have an option and be sure it’ll be fine.
Jokes aside, these kinds of boxes are by far my favorites. Fancy leather boxes are cool…but 5 minutes while unboxing, then they land in your closet. This one you can use even daily, you don’t even have to carry your headphones inside…do you know how expensive pistol cases are?!
Inside, you’ll find some cool stickers, a cable, documentation, and that’s pretty much it. The cable itself is very nice, premium, and comfortable to use, so kudos for that.
Overall, the packaging is peak, no doubts about it. Premium, yet useful, and actually well fitting the vibe of the product. Nice.
Design, Build Quality, and Comfort of ZMF Caldera Open
Boy, oh boy, we’re just getting started. If you’re into wood, metal, and real leather, you’ll be amazed here.
This is definitely one of the sexiest and best-built headphones on the market. Different vibe than Meze Audio and their Empyrean 2, but in many ways, it’s the same level of luxury. Nothing else comes close to this, by quite a margin, actually.
The Caldera is a chunky headphone, but also a VERY comfortable one. Thanks to its superb headband construction, plush and soft earpads, and fantastic weight distribution, I was able to easily wear them for the whole day without any issues whatsoever. Yes, the leather gets a bit hot during extreme temperatures outside, but hey…if you can afford them, you can also afford A/C. That’s obviously a joke…or is it?
I’ve mentioned wood, so you’d probably ask – what kind? It’s not that simple. The wood used in the Caldera depends on the moment you’re going to order these.
Right now, the current stock of the Caldera Open is made of Zebrawood, paired with coffee gold grilles. You can also order an upgraded version, which uses magnesium instead of aluminum for the chassis. Black rods are also a choice.
To be honest, I’m feeling a little bit lost when looking at it. There’s also an LTD shop with…you guess it, limited versions of ZMF headphones, often in stabilized wood. And you know, I’m a simple man, I see stabilized wood, I like it.
Well, I’m pretty sure you can also message ZMF directly and just splash the cash for some super fancy, one-of-a-kind, custom version of the headphone you’d like to buy. These guys are super passionate about their work, so I can’t imagine them saying no to that.
However, the “standard” choices are so beautiful and unique already that it’s definitely not necessary. And trust me, the photos don’t even show 30% of the refinement of this product. You have to see it with your own eyes, touch it with your own hands to understand. Absolutely epic.
Tech
At one point in this review, I told you that ZMF is not about cutting-edge technology. Well…that might have been a lie, actually.
When creating the Caldera, ZMF didn’t decide to just buy an existing planar-magnetic driver or create its own, basic, and “everyone saw it already” type of technology. They went a step further…or a few steps to be precise.
First of all, the heart of the Caldera is an 80mm Planar-Magnetic driver with 2 μm thickness, rated at 60Ω and around 95db. But what’s most important comes next…
Here comes CAMS, which stands for Caldera Asymmetrical Magnet Structure. This is ZMF’s proprietary magnet structure, which was created to counter the biggest problems that usually come bundled with large planar drivers.
The keyword here is asymmetrical.
Instead of using conventional symmetrical magnets on both sides of the diaphragm, ZMF uses an asymmetrical magnet structure.
The design is intended to:
- maintain a uniform magnetic force across the diaphragm
- reduce the obstruction caused by the magnets to the airflow
- direct acoustic energy toward the ear
- while also delivering greater dynamics and slam.
The idea is to provide the air with the least obstructed path possible from the diaphragm to the ear. This should give us enhanced dynamics and a sense of physicality and weight of the sound. I’ll share my thoughts on this one in the sound section of the review.
That’s all, folks…well, not really. There’s also ADS, which is a shortcut for Atrium Damping System. Yes, it says Atrium, but I’m not mistaken here, bear with me.
This technology was created to control what happens behind the driver. Remember that big planar drivers generate a lot of energy towards the front of the driver, but also the back. If you just enclose that driver from the rear side, you’ll end up with a lot of reflections and resonance.
Here comes the ADS, which is basically a specially prepared acoustic environment created to disperse the energy on the “back” side of the driver. For non-technical people, this might sound like some wizard spells being cast by Zach himself…but hey, if you think about it and read about it, it really makes sense.
To summarize, the idea behind the Caldera wasn’t to just “stick a planar-magnetic driver inside and call it a day”. It was a process that took a lot of testing and finding very smart solutions, and then patenting them. Smart move.
Sound of the reviewed ZMF Caldera
We audiophiles are a different breed, though. All of those marketing names with big descriptions would have been for nothing if the product didn’t sound good, right?
That’s right, and that’s how it’s supposed to be, really. I respect going an extra mile or two to ensure the technical and acoustic perfection for your product, but it’s what it sounds like that really matters. So let’s get right into it.
At the very beginning of this review, I told you that I’ve been trying to put my hands on the Caldera Open for quite some time. It all began a few years ago at High-End Munich (Vienna now), when I had the pleasure of meeting Zach and Bevin for the first time.
I’m not really a fan of testing stuff and listening to audio products on shows like that. I usually test only a few things that really interest me, but that’s a very, very brief test that I’m never really treating seriously. But on that hot day (oh, I remember it was like 32 °C and I decided to take a long walk to the venue…wasn’t the top 5 best ideas of my life), Bevin convinced me to try their Caldera.
I’ve heard a handful of positive feedback on this specific model. It looked great, so I decided to give it a go, why not?
What happened next was unexpected to say the least. I almost never say that about headphones I test during exhibitions like that, but I was blown away by this specific one. The sheer musicality and fun of the Caldera grasped me so hard, and wouldn’t let go. My time there was very limited, so sadly I had to take them off my head, but I remember saying to Bevin something like “THIS IS NUTS”.
After I came back home, I immediately messaged Bevin to find an opportunity to test the Caldera here at my home. I was trying to get them loaned to me for a few months, because I knew 2-3 weeks wouldn’t be enough for this specific headphone. Long story short, a few years later, here we are.
And we need to go back to my “2010 was cool” paragraph I wrote earlier. Why? Because the Caldera does not only look like it’s been released around that time…it kinda sounds like that too, but in a very good way.
Do you remember the times when it all wasn’t just about who makes the most neutral, transparent-sounding headphones? When Planar headphones were coming back, they offered something so much different than everything else. Back then, you had the legends like the Sennheiser HD800, Beyerdynamic T1, AKG K701, and some others. Then came HiFiMAN and Audeze with their thick, melodic, and ultra-rich sound signatures that offered something totally unique and almost mesmerizing.
These times are long gone, but headphones like the Caldera are a beautiful homage to those times. It’s a somewhat similar story to that of the Meze POET, which was awarded the “Best Product 2025” award by Ear Fidelity, actually. And it got it for the thing I’m currently explaining to you.
But damn, the Caldera might just take it up a notch even further. This is PEAK musicality in the headphones world, and I’m 100% damn serious.
The bass has a lot of weight and meat to the bone for a planar headphone. It has that deep rumble when needed, that sheer energy and kick to it. At the same time, it’s fast, agile, tactical, and very well-textured. If you’ve been in this hobby for a while, then you probably know that planars don’t really offer a strong, dynamic, and punchy bass response in general, and that’s by far the biggest con of this technology. At the end of the day, basically, most of the high-end planar headphones can be easily described as bass-light, which is a big, big problem with the industry in my opinion.
ZMF came as close to solving this issue as I’ve personally experienced with the Caldera. This doesn’t really sound like a planar bass when it comes to its usual weaknesses. But it definitely possesses all the strengths that we all fell in love with planars for.
The midrange is quite simply godlike here, and I’m not even exaggerating. Its timbre, warmth, big body, and richness are all top-tier, regardless of the price range. This is Susvara level when it comes to maturity and enjoyment.
However, it’s not gooey, slow, or overly syrupy sounding. It’s a big planar after all, so you can expect fantastic detail retrieval, infinite resolution, and spaciousness of the sound. But now, combined with a timbre that you can fall in love with instantly, and never let go.
Doesn’t matter if you prefer male or female vocals; these babies got you covered. Male vocals have that richness, presence, and weight to them, with exceptional vibrato representation. The vocal comes slightly forward towards you, which is exactly what my preference in headphones is. It all just sounds so natural, so lifelike and unforced, that you’ll forget you’re listening to a pair of headphones, for real.
Female vocals are sweet, romantic, and totally captivating. There’s a beautiful, higher midrange timbre that makes it sound as if you were there. Supported with an exceptional amount of air and separation, this creates a sound that is both hyper-detailed and very easy to listen to for hours at the same time. Bonkers.
The treble continues the slight boost that you’re getting with the higher midrange, but it’s really not major. I’m really sensitive to the midrange/treble region, and the Caldera was just perfect for me. It has that perfect combination of just enough boost for the vocals and details to come forward, yet not sounding harsh or unpleasant. I can kinda compare it to the OG Campfire Andromeda, which was famous for the exact same reason. A slight boost that just seems to be perfect for the majority of people.
Because of that, you’re getting that grand presentation, spacious soundstage, and very large instruments. There’s so much air in this presentation that the Caldera gives you a sense of scale that is mostly reserved for very good speakers.
The cymbals have proper weight to them, thickness and spark, and they don’t sound thin whatsoever, which is VERY important for me personally. A lot of people have no idea what drums cymbals really sound like in real life, so I encourage everyone to go and visit your local music shop, and just smash that baby. Quite possibly you’ll be surprised.
The Caldera handles those things like a champ, creating a sound that always sounds just right, natural, and incredibly exciting.
Because of all of that, the Caldera Open is a fantastic choice for every single music genre, basically. Properly romantic and sweet for acoustic music and jazz, big and bold for electronic music and metal, and everything in between, basically. Even large orchestras, with its airy and spacious presentation, sound incredible here.
On the other hand, I’m aware that this isn’t the last word in the world when it comes to detail retrieval, especially in the micro-detail region. It’s not meant to be, though. This headphone was made to give you fun and send chills down your spine, and they do that, and then more.
If I were to explain the Caldera Open with one word (yes, that’s a stupid idea), this word would be MUSIC.
Edit: Sadly, even though I received some extra earpads in the box with the Caldera, I haven’t tested them. The last few months were crazy due to the fact that I bought a house, and I’m still not done setting it up. In the meantime, work ain’t gonna do itself, and there are also reviews responsibilities. Maybe in the future I’ll be able to test them and update this review.
Comparisons
HiFiMAN Susvara
This comparison just had to be mentioned. After all, we’re comparing the Caldera to the most legendary high-end headphones of this century.
While these two share some similarities when it comes to musicality and air, they are quite a lot different from each other.
The Susvara is definitely lighter on the bass, less punchy, and energetic. The midrange is also thinner on the HiFiMAN flagship, but also more detailed and refined. The treble is just a masterclass in the Susvara, followed closely by the Sweet yet airy treble of the Caldera.
While I would still consider the Susvara to be a slightly better headphone overall, the Caldera is even more engaging with its bold, big, and juicy type of presentation.
Choosing between these two should come down to what you’re prioritizing mostly. If you want a jack of all trades, a headphone so technically impressive it’s actually ridiculous, you just can’t go wrong with the Susvara, it’s a legend for these requirements.
However, if you feel like the Susvara is a bit too gentle, anemic, and delicate for you, the Caldera will be perfect for you. It just sounds bigger, fuller, and even sweeter in the midrange. Damn, this is really impressive.
I’ve already mentioned the Poet in this review, but let’s get back to it.
These two headphones really sound like they were released a good 15 years ago, in a good way. However, they give you that vibe in different tastes.
The Meze Poet is a very calming, smooth, and hyper-relaxing type of presentation that is just perfect for chilling in your Herman Miller Eames. You just pour yourself a glass of something nice and fancy, hit play, and finish in the morning. Kinda been there, done that…don’t judge me.
The Caldera also has that beautiful and smooth midrange presentation, but the overall sound is much more energetic and forward. It works better in electronic and rock music, which demand that level of presence.
The Poet is a guy in a very expensive suit that goes to his favorite jazz club every Friday for the past 30 years. The Caldera is an elegant guy who wears a double-breasted jacket on Fridays and goes to the same jazz club, but every Saturday, he puts on a leather jacket and goes all in right into the middle of a pogo dance.
This comparison is somewhat similar to that with the OG Susvara, but to a bigger extreme, actually. The Susvara Unveiled is even more focused on the technical aspect of the sound, being the fastest, most detailed, and spacious.
The Caldera isn’t really a match to the Susvara Unveiled in those aspects, but I don’t think it was even supposed to be one.
Actually, this is the perfect example of “buy both and retire from the hobby”. You’ll basically have two absolutely incredible headphones that give you a totally opposite type of vibe and two different sets of strengths.
And even though I respect the Susvara Unveiled A LOT, when I’m back home and just want to kick back and relax with my favorite music…my hand goes for the Caldera. Every. Single. Time.
Seems like we’re continuing the comparisons when two headphones are vastly different. Now it’s time for the Audeze LCD-5, the flagship by this American company.
Compared to the Caldera, the LCD-5 has basically no bass at all. It sounds really thin in comparison, to the point where it kinda sounds wrong, actually.
On the other hand, the treble of the LCD-5 is most likely the best in this hobby, so this is a mixed bag, I suppose. A Caldera with the treble performance of the LCD-5 would have (most likely) been the best headphones in the market.
Choosing between the two is quite simple here. If you want a microscope for your music, an unreal level of resolution, detail retrieval, and a treble response to die for – go for the LCD-5 and never look back.
If you want music, you get the Caldera. It’s pretty much that simple.
Oh, this is getting interesting. For a few years now, ever since 2022, the RAD-0 has been my go-to headphone for metal and some strong, powerful synthwave songs.
On the other hand, the Caldera handles those genres like a champion…so which one should you choose?
The RAD-0 sounds more raw, brutal, and uncensored. The Caldera, on the other hand, has more warmth and more magic in the midrange. So even though both give you somewhat similar results, their way of achieving that is vastly different.
I just love both of these headphones, and I would have had a very hard choice if I had to choose one. Yes, the Caldera is more refined, more spacious, and open-sounding, so if that’s your jam, then go for it.
Pairings
The ZMF Caldera might not be the most demanding headphone in the world, but it surely scales a lot with better equipment. Let’s be real, this is such a beautifully sounding headphone that definitely deserves a high-end company.
I don’t see any issues pairing them with an R2R DACs. Yes, for the most part, they are on a smoother side, but the Caldera has so much energy that it’s not a problem. Something like the Denafrips Pontus or above, or the Laiv Harmony DAC would be both exceptional choices.
On the other hand, the amplifier to pair the Caldera with should be a powerful, clean, and engaging one. It would have been a shame to tame them by not driving them to their full potential.
They sounded very good via the HiFiMAN Serenade, but ever since I plugged them into my Feliks Audio Envy, it was basically GG.
If you want a tube amp, make sure it’s a powerful one. Then you’re golden.
Portable stuff? You can do whatever you want, but it’s not the type of headphone to do that, really. If you really have to, then sure, go for it. But if that’s possible, just give it a big-boy desktop stuff and enjoy…and trust me, you will enjoy this a lot.
ZMF Caldera Review – Summary
The ZMF Caldera Open is an extraordinary pair of headphones in every aspect, combining exceptional craftsmanship and gorgeous design with a beautifully rich, romantic, and deeply engaging sound.
You’re truly buying something extraordinary and unique here, and you’re supporting good people by doing that (cheers Zach and Bevin!).
This is one of the most exciting reviews I’ve done in a long, long time…and the day I had to ship these back was a sad one. The Caldera is a fantastic future classic, without a doubt.
Wildly recommended.
Big thanks to ZMF for loaning us the ZMF Caldera for this review. I wasn’t paid or asked to say anything good or bad about this product, all of the above is just my personal, unbiased opinion.
Founder of Ear Fidelity. I’ve been into audio for many years, working in production, distribution, retail, and marketing throughout my career. Now trying to revolutionize the art of reviewing audio gear, but one thing will never change: Music is the most important.
