ZMF Headphones Caldera Closed featured image

ZMF Headphones Caldera Closed Review

Today, Marcus reviews the ZMF Headphones Caldera Closed, which is a recently launched set of flagship closed-back 80m planar magnetic driver headphones. It is priced at $3499.

Disclaimer: This sample was sent to me in exchange for my honest opinion. Headfonics is an independent website with no affiliate links or status. I thank ZMF Headphones for this opportunity.

You can click here to learn more about the ZMF Headphones products I have previously covered on Headfonics.

Note, that this article follows our latest scoring guidelines which you can read in more detail here.

ZMF Headphones Caldera Closed featured image
ZMF Headphones Caldera Closed Review
Summary
The ZMF Headphones Caldera is a very easy recommendation to make if someone is after a set of high-end closed-back planar headphones. These headphones are for those who have tested the open back version and want a bit more body, more weight in the lows, and that key strength of any closed-back, the improved levels of passive isolation. 
Sound Quality
9.3
Design
9.2
Comfort & Isolation
9.2
Synergy
9.4
Slide here to add your score on the gear!46 Votes
9.2
Pros
Enhanced low-end body over the open version
Beautiful wood grain choice
Lot of pads choices, lots of sound signatures.
Cons
Cup shape is unique and some will love it and some not
Higher impedance tube amps may come across as muddy
9.3
Award Score

If you know ZMF Headphones you should their headphones almost always come in twos. If there is an open-back release or vice versa then as sure as ‘Death and Taxes’ there will probably be a closed-back version released shortly after.

And so it is the case with the Top Gear 2022 Award-winning headphones, the Caldera, and the recently announced Caldera Closed sibling.

Both are planar magnetic headphones, both carry the title of being the company’s flagship headphones, and both are priced the same at $3499. Is it a case of ‘same, same’? Most definitely not. From the external design to the tuning, the Caldera Closed is a unique proposition to its open-back brother.

I suspect Caldera Open fans might be less tempted as it is the superior headphone on a technical level.

However, for those without either and debating between the two the Caldera Closed will serve different needs. From my testing, I believe it will appeal to those who want the Caldera ‘sound’ but with a superior level of passive isolation and a weightier bass response. 

ZMF Headphones Caldera Closed on their side

Features

The ZMF Headphones Caldera Closed are full-sized closed-back headphones with the same proprietary planar driver as the open version. 

This is an 80mm planar driver with a 61mm active moving surface area, all encased in a carbon fiber baffle to keep the weight from the coil and magnet array down to a fairly comfortable level for putting on your head.

The driver materials consist of gold-plated copper for its 4 traces and 8 pathway patterns with a special silver coating to maximize excursion along the traces. The exact diaphragm thickness is 2um so not quite Susvara-level nano-thickness. 

Unsurprisingly, the Caldera Closed has a rating close to the open version at 60Ω impedance and an SPL of 94 dB/mW @1kHz. It is not quite as efficient as some of the planar competition out there but sensitive enough to work well with moderately powered headphone amps.

ADS Tweaks

What is different, however, is the adaptation of the Atrium Damping System, (ADS), for the Caldera Closed-back version when compared to the previous open-back design. In some ways, it’s a similar application to the Atrium Closed version.

The Caldera Closed ADS system starts similar to the Open version in that the primary damper is neither attached directly to the rear of the driver nor the back of the cup, essentially “floating” in the cup volume.

However, unlike the open design, it also includes segmented diffusion so that energy is dissipated in concert with a typically used asymmetrical cup design that minimizes standing waves.

Essentially this creates stages of diffusion rather than one central diffuser to ensure a natural decay of the notes so that soundstage and timbre do not sound as ‘walled-in’ as you would expect from a closed back.

ZMF Headphones Caldera Closed standing upright cup side

Design

Cups

As always with ZMF, the distinctive headphones frame and articulation are unchanged as also using wood for the cups, the more striking visually the better I think is the mantra here.

The Caldera Closed is no exception with two day-1 options including a strongly grained Shou Sugi Ban ash wood which is the sample I have here and a more limited edition Shedua wood alternative.

I have also seen a gorgeous Queensland Maple prototype edition do the rounds online which also looks stunning so I hope that will be an option also.

For those unaware, Shou Sugi Ban is a Japanese burning process used for preserving wood and making it more resistant to the elements. It can be applied to many types of woods but in this case, ZMF has chosen ash for the Caldera Closed cups and I can see why.

One of the benefits of Shou Sugi Ban is the way it can bring out and highlight the woodgrain in a way that other finishes cannot. Since ash is a light-colored wood, the grain saturation is amplified many times over giving the cups a very striking and unique visual effect.

ZMF Headphones Caldera Closed standing upright

Caldera Delta

And it is not just the grain, but also the cup form factor that has been given a bit of an overhaul. Instead of the usual smooth vented dome, the Caldera Closed cups have what could be described as a raised ‘Caldera Delta’ geometric curve through the middle that gives the cups a very unique shape. 

Zach, (Merbach), has described this as an emulation of a volcanic creator, especially when you put both cup shapes side by side. 

It looks cool and quite different to the Caldera open design but I also suspect some traditionalists will shy away from the more aggressive lines on the cups. I also think some woods will shine more than others with the new dome dimensions.

For example, the Shou Sugi Ban ash wood finish version looks aggressive and accentuated with that heavy grain line running counter to the triangle. However, the Queensland Maple prototype version I have seen online looks elegant and stately. There will be lovers of both I am sure.

ZMF Headphones Caldera Closed earpads

Comfort & Isolation

There isn’t a huge weight difference between the Caldera Closed and the open-back alternative. Just a 10g weight difference for the stock ash edition at 500g with a design that mitigates that weight well for a full-sized planar headphone with wood cups on either side. 

The Caldera Closed frame is unchanged from previous ZMF models with only the pads getting a bit of an overhaul and switching to a new hybrid variant.

That means current ZMF headphone owners will be very familiar with the resting and pressure properties of the Caldera Closed’s headband and pressure strap.

Overall, the Caldera Closed is very comfortable. Yes, you will notice its presence on your head, it is 500g and on the larger side. However, the pressure distribution is excellent with the pads doing an excellent job of mitigating any potential for discomfort from the lateral clamping. 

The adjustable crescent pressure strap combined with the notchy rod adjuster system and the 360-degree articulation in the cups will also give you plenty of room to adjust your head height and shape.

ZMF Headphones Caldera deep pads

Ear Pads

The Caldera Closed stock ear pads are a new design. These are the Caldera Hybrid pads with a lamb leather outer, perforated on the narrower contact surface and finished with a solid suede inner wall.

They are not as perforated or deep as the stock Caldera Open pads so your ears will sit closer to the driver when wearing them. They also have a wider opening when compared to the Caldera Open stock pads, with a slightly fluted finish.

The passive isolation is slightly lower than the Atrium Closed stock pads but still quite good. I suspect the fabric inner wall is a bit more porous allowing for more background noise to creep in.

That being said, the full lambskin Caldera Thick pad option improves on the isolation and is on par with the Atrium Closed performance.

Like any ZMF Headphones build, the ear pads are detachable with a spare set of ‘Caldera Thick’ pads and the optional Bokeh Protein pads that were also sent with our sample. 

They have a similar form factor as the Hybrid stock pads with the wide fluted inner opening but instead of a suede inner wall, it’s a matching non-perforated leather finish. The comfort levels are much the same but isolate a bit better when compared to the Hybrid pads. 

ZMF Headphones Atrium Review

Stock Cable

The Caldera Closed will come with ZMF’s stock braided balanced cable and single-ended alternative. These are both 5.5ft cables with the braided using a balanced 4-pin XLR/mini-XLR option and the other being single-ended with a 6.35mm jack and mini-XLR connectors.

The balanced version is an insulated copper wire with a twisted nylon jacket finish and a black-finished aluminum funnel-type splitter. The mini-XLR pins are terminated ‘Audeze’ style so their polarization is fairly standard.

The SE alternative is a 24AWG 4-conductor OFC copper wire with aluminum and copper shielding housed in a rubbery external jacket with the same black branded splitter and mini-XLR connectors. The 6.35mm barrel is wrapped in heat shrink with strain relief internalized.

The supplied balanced cable has low microphonics and very little in the way of memory retention. It handles very smoothly and compared to the SE rubbery version it’s my preferred cable with slightly better flexibility.

ZMF Headphones Caldera Closed inside carry case

Packaging & Accessories

ZMF has a fairly set pattern for their headphone packaging and accessories so it is no surprise that the Caldera Closed comes with a similar presentation to our previously reviewed open version.

That means a very sturdy and large, black-colored, weather-sealed carry case with plenty of internal soft foam padding for the Caldera Closed headphones, the accessories, and the cables in their small pouches.

You also get the two cables in a nice little cloth sack as well as an array of paperwork in a small envelope to indicate your Caldera Closed build type, a QC check card, and a catalog of ZMF Headphone products and earpad options.

One additional new item at the bottom of my sample box was an ear pad chart giving you a wide range of options that you can fit with the Caldera Closed including other significant ZMF headphone models.

The card also informs you of what pads are installed out of the box and the wood finish of your cups, (hand-wiped wax oil). This is a useful card for picking the right ear pads, not just for this headphone but for the entire range

Click on page 2 below for my sound impressions and recommended pairings.

Click on page 3 below for my selected comparisons.

Sharing is caring!