Mantle Mesh and Pads

While the different wood options for the ear cups can have a slight impact on the sound signature of the ZMF Caldera, I think it's safe to say that most people will be choosing the limited options primarily on looks. Where you get more customization options over the tuning of the Caldera is with ZMF's DIY parts. The company relies primarily on back damping here, as seen on the previous page, which helps keep the sound lively and engaging. But there are still occasions where the upper mids and lower treble might come off bright to some depending on their HRTF and this is where the mantle mesh comes in. It costs $20 and comes in a set of three even though you only need two, perhaps the third could be a spare for later or to practice installation. A set includes shaped tape as well as the mesh itself which is made of titanium. Align the mesh over the driver, peel off the tape cover, stick the two together as seen above—that's it. It's quite simple and the holes in the tape going over the black screws in the driver assembly also help confirm you have done it correctly. You can peel it off and try again if you didn't get it correctly and this also means you can perhaps play around a bit with different pads and mantle mesh combinations but in general I'd recommend sticking with the combination you have and having the mesh be permanently on or not. The end result is basically slightly more damping which lowers the presence in the upper mids and higher frequencies. This can help make the Caldera more bearable for those who found it bright and fatiguing perhaps, although I personally didn't like it. If anything, I would be more inclined to add a tiny treble shelf filter than cut things down further with the mantle mesh taking away some 2nd and 3rd-order harmonic presence from vocals, violins, and cymbals. I still appreciate this is an option though, and I agree with ZMF that this should not be installed by default.



Now we get to the various ear pads and we've seen before how much pads can affect the sound of headphones. ZMF noted how I was curious about the different ear pads, and indeed I had many asking me to test the Caldera with different pads, and sent over four sets including a new set of the stock pads that was used for most of the testing. Then add to this at least 3-4 days per pad type and you can see how much time went into this review. I feel it's worth it though since the Caldera pads are extremely promising for comfort and sound while having an increased compatibility with different headphones. In fact, there are already third-party headphones being sold which use the Caldera pads so this experience can also help in the future.

First up, the ZMF Caldera cowhide thin pads which come in a neat earpad bag. As the name suggests, the base leather is made from cowhide rather than lambskin and is thinner than the stock pads too. It is also fluted in design but feels less obvious as a result of the denser composition and slightly stiffer surface which also means you don't get the same plush support with these pads. The ear spacing is the same from top to bottom although the height is of course reduced here. I didn't have any issues fitting the Caldera with these on even if actually getting them on was not as simple. The photos comparing these to the stock pads reveals a similar nature of perforation on the contact surface and outside but not inside. The thickness isn't different enough to make a tangible difference on the clamp force but the pads sure change the sound in a big way. I found the variable soundstage to be gone and replaced by a fairly cramped one this time. Bass felt more intense too and there is something to be said about increased contrast as well even more body to the lower mids but the end result in tonality is one I wasn't a fan of. The Caldera now almost comes off U-shaped with darker upper mids and lower treble which in turn emphasize the lows and highs further. The mantle mesh is already a teaser of how these pads sound with the Caldera and it wasn't for me since I'd personally go with the stock lambskin pads any day of the week. I suppose if all you cared about was how the Caldera put out the lower frequencies and wanted more of it, perhaps these pads will be worth trying.



The vegan suede pads are the only choice for those who don't partake in leather products and these can be paired with a vegan suede headband strap too when ordering the Caldera. These don't feel like a compromise by any means either compared to the leather options with the pads retaining a premium feel to the touch and the light green shade also being cool if I say so myself. These are also the closest to the stock lambskin pads in thickness and perforation as evident from the photos above. In fact, the comparisons hold up further when you see the tuning being very similar too. If the Caldera with these suede pads also sounded exactly like the stock leather pads then this would have been remarkable for vegans. Unfortunately looks can be deceiving with the suede pads losing a lot of that lively, thick sound signature. The Caldera feels more diffused, especially in the sub-bass and mid-bass, and has less weight in the mids too. On the plus side, the suede pads don't run as warm in the summer and can be more comfortable if you found the Caldera clamp force to be a touch too high. Female vocals are more likely to feel uniformly prominent with these pads and if you wanted more air for cymbals/triangles/harps etc then that increased presence <15 kHz isn't just a measurement artifact. The suede pads almost feel like they are on the other end of the pad effect spectrum as the cowhide thin pads and yet once again I'd stick with the stock lambskin pads if I had no issues with leather.




Rounding off the list is the only set of pads which is perforated on the inside too, resulting in further airflow through the pads. Aptly named the lambskin ultra perf, these retain the same thickness and the exact same fluted nature of the stock lambskin pads but with extra perforation which is easily evident from the photos above. They may seem slightly smaller than the stock pads but it's more an optical illusion as they fit over the ears exactly the same. I will also add that these are the most open feeling of all the pads and can be more comfortable in summer too. The end result is a sound which is more reminiscent of old-school orthodynamic headphones with a bass drop-off that results in pretty much more energy in the sub-bass. The mids are also far more forward now and I didn't have the natural timbre and heft anymore. Instead, I found myself with a wider and taller soundstage and a more diffused, airy sound which worked nicely for classical music—string quartets especially. The mantle mesh has a viable place with these pads too if you liked this presentation but wanted less energy in the mids. These sound like a completely different set of headphones now though and not the ZMF Caldera as most people talk about it. It's not for everyone and ZMF too didn't recommend these pads for the Caldera, yet I see potential for specific music libraries such as mine as well as those with more Asian pop music perhaps.

I do see why ZMF has chosen the stock pads now as those are simply the best sounding and balanced set out of the ones tested. Knowing what I know now, I might have asked for the lambskin thick pads instead of the cowhide pads—the suede pads are too important to ignore—since I feel like they have the best chance of adding an ethereal sound to the Caldera without compromising too much elsewhere. There's also the lambskin thin option which suggests the stock pads are effectively "lambkin medium." But if I had purchased the stock Caldera with my own money then honestly I'd probably skip pad-swapping altogether and try to swap the entire headphones for a limited edition. As I type this review, there's a brand new set of Caldera LTDs being sold as part of ZMF November 2023 and they all look amazing.

Comparisons

The ZMF Caldera finds itself in a price range where most flagships cost more and the next tier is a good amount lower. However, a lot of the other flagships can be found for less owing to their time on the market as well as sales being more common these days. There's also an argument to be made about the Caldera being ZMF's flagship to take on the more expensive flagships from larger brands. So it makes sense to go this route and the obvious comparisons come from planar world with the Audeze LCD-5 and HIFIMAN Susvara. The LCD-5 is the result of Audeze trying its best to address the complaints of previous flagships being overly heavy and the end result is a smaller set of open-back headphones which weighs less than the Caldera in either iteration. But the Caldera still feels more comfortable owing to the clamp force, the increased fit customization, and the headband + pads combination. The LCD-5 pads are also sculpted like the Caldera pads but have less contact surface on the skin to where there is more pressure in use. The acetate ear cups have been divisive too with many preferring wood and the Caldera is what comes to mind immediately in this regard. Tonally the LCD-5 has flatter mids and bass extension all the way down to 20 Hz, if not lower, and goes for a more Harman-like ear gain which makes it an easier tool for professionals in the music industry—having virtual studio support and HRTF profiles with Reveal+ and Embody's IVS also helps there. It is also more detailed across the entire frequency range than anything else I have heard although the darker sound in the higher frequencies followed by the upper treble increase can be jarring. It's a great set with EQ and yet is one of those planars which people think of when they complain about timbre and potentially lean mids. The Caldera can be more engaging out of the box and still give you a great time without feeling like you have to pay extra for that über flagship experience. Out of the box, I can see myself going for a cool stabilized set of the Caldera and using the difference for an amplifier. The LCD-5 can be found second-hand for less though, but perhaps that says something about where the market things these two should be priced at too.

The HIFIMAN Susvara is almost perfectly tuned to my HRTF so purely as a result of this I am biased towards it. It scales beautifully with a nice amplifier, which is a kind way of saying you may have to spend a lot on the amplifier to make the most of the demanding Susvara, and can be found for ~$500-1000 more than the Caldera. This is a lot admittedly, especially with the amping requirements, but you get a more resolving set which isn't fatiguing as well while still retaining a relatively smooth treble response. It's an all-rounder set that works for a variety of genres too, so personally I'd look at a second-hand or B-stock Susvara. Yet there is no denying that HIFIMAN can be found wanting in build quality and QA checks, whereas the Caldera gives you a lifetime warranty on the drivers which is cool. The Caldera also comes in a wide variety of one-off releases in addition to the customizations for the stock versions with the chassis, wood, grill/yoke rods, and pads/mesh alike. It's a set that you can make your own too, especially if ZMF is bringing back the custom boutique service it was known for, and let's not forget that you do get a fairly unique sound that is still well executed courtesy the thicker mids.

I wish I had more dynamic driver headphones in this price range to talk about, especially when ZMF itself is known for its Atrium/Verite/Auteur line of open-back dynamic driver headphones. In their absence, Focal will have to do with the new Utopia featuring beryllium drivers and years of R&D from making speaker drivers and enclosures for a variety of use cases. The new Utopia oozes luxury the moment you see it and has an unboxing experience that gets you excited despite it being the most expensive set in this comparison. I no longer have it here since it was on loan from a local PR firm, not Focal directly, so apologies for not having a photo of the Caldera alongside. The review will have plenty though and we can see how it's predominantly black with some red accents. It's a single SKU, as with the LCD-5 and Susvara, and is the most dynamic set I've heard in being able to discern a wider range of louder and quieter tones at the same time. The Caldera feels like a mix between the Utopia and the Susvara in terms of decay and weight, going for a warmer tone than the others with increased sub-bass presence than the Utopia—on the stock pads anyway. The Utopia was equally comfortable to me as the Caldera over longer sessions although the Caldera is easier on the head right away and feels more secure too. The Caldera stages wider and taller too while also enabling better layering of complex tracks. It's also got more lower- and mid-treble presence to where, while I did add an EQ filter on the Utopia, I never felt it was a must-have here. Both are easy to drive compared to a lot of expensive headphones on the market today though, but this one is pretty easy and I'd take the Caldera any day for the cost savings and the variety of custom options. The Caldera will also be a lot less expensive to maintain over time given the Utopia pads cost nearly thrice as much!

Then there's Meze Audio which puts out some beautiful and extremely comfortable headphones. The Meze Elite is my benchmark for headphone comfort and I mentioned before how the Caldera reminded me of it too. I had thankfully just heard the Elite (and the Utopia) to not rely too much on auditory memory—which is more deceptive than you might think—and the warm/relaxed tonality of the Elite isn't that far off. The Elite goes a bit too much down that road while sacrificing on the technical performance—dynamics, resolution, timbre—for me though so the Caldera again makes its adaptive strengths visible. The HIFIMAN HE1000se was priced exactly the same as the Caldera until recently but I really can't recommend it for even the current $2000 when you can get the HE1000 Stealth which does a much better job for less. In fact, the Caldera almost feels like a souped-up HE1000 Stealth in offering more mid-bass and body but controlling the treble significantly.