ZMF Caldera Review and Impressions

After 48h of continuous burn-in, Oor>Caldera gained coherence and refinement, with strings and wind instruments gaining definition and heft, while maintaining separation & layering. Listening to a very busy track with acoustic and electric instruments by Gordon Grdina's "Haram" ensemble, I could easily attend to each instrument very distinctively within the sound image.

 

I have Hypsos as well, as I want to explore orthos a bit, starting with Caldera for now.

 

Further impressions: listening to Mance Lipscomb's "You Got to Reap What You Sow" after watching a wonderful documentary on him "A Well Spent Life." Oor>Caldera renders all the fine details and roughness in Lipscomb's voice and his guitar playing, while keeping a clear separation between voice and guitar. He could be sitting just across me. This combo sits at an interesting sweet spot: neither wet nor bone dry, excels in separation and depth, not analytical but full of detail, engaging.

I guess I'll pass on that Zähl HM1 <ducks rotten fruit and eggs>

 

HQPlayer>May>Oor>Caldera assessment continuing, after some 100h of burn-in: this chain is the first one I've owned that gives HQPlayer>May>Stellaris (with fancy tubes)>Atrium serious competition. It's different as I noted earlier: more open, more space like being in SFJAZZ's Miner auditorium in seat row D or so, while the other setup is more intimate, like one of the front-side tables at the Village Vanguard. Stellaris>Atrium is more relaxing, Oor>Caldera more "wow, this music is intense!."

Caldera has come together across the frequency range now, coherent energy across the spectrum for small-ensemble jazz. Listening to Art Hirahara on "Peonia" ("Open Sky" album), and the setup makes me almost "see" his hands, with the high and low notes so well separated and yet forming a coherent sound picture.

Jazz vibraphone and xylophone are really intense and yet delicate with this setup, all the overtones are there but with zero "aura" around them, while with Stellaris>May there's a subtle aura that makes them more romantic but less driving.

TL; DR Two great setups for two different moods, so much music to explore again, so lucky that I can enjoy the outstanding craft of the outstanding designers and engineers at Signalyst, Holo Audio, DNA, Ferrum, and ZMF. You all make recorded music come live again!

 

One more Oor>Caldera comment: listening to Wadada Leo Smith's "Pacifica Koral Reef" with Henry Kayser and Alex Varty on guitars, those guitar string attacks are *fast* and the decays trail into silence without truncation, overtones all present, as if the Caldera drivers were "impersonating" the strings. This setup achieves a level of physical immediacy for some material/instruments/recording conditions beyond what I was used to, which the as always superbly recorded WLS work takes full advantage of. Speaking of which, his trumpet seems right here a few feet away, all breaths and roughnesses, like last time I heard WLS from the front row at SFJAZZ.

 

I also seem to get a better synergy with the Caldera with a neutral-tilted amp. Initially the Cayin HA-300 MK2 (SET 300B, warm leaning sound but very suitable for planars) didn't impress because it introduced too much bloom into the headphone but my own HeadAmp GS-X MK2 (with custom Kevin Gilmore's golden reference dual mono power supply) seems to fare much better. It's just a bit strange because that Cayin does amazingly well with the Verite and Atrium. I still think that Susvara remains the most natural, refined and delicate when it comes to resolution and timbre but now with proper amp pairing the Caldera is not too far behind while maintaining the ZMF house sound and can be a good alternatively if you desire a more traditional dynamic driver sound.

Hmm... I think the next order of business is to test the Caldera with neutral-tilted tube amps that do well with planars like Woo WA33, Ultrasonic Telemachus and Riviera AIC-10 (this one is a hybrid SS/tube but it's extremely well tuned).

 

ZMF Caldera Loaner Impressions

Once again, big thanks to @zach915m for loaning us his latest creation and @ChaChaRealSmooth for putting the loaner together!

Preamble

You can read the Preamble and Preferences sections from my Atrium loaner impressions here.

The loaner only came with the stock lambskin perforated pads. I used my own Forza Noir Hybrid HPC at first, but then switched to the stock 4-pin cable.

Setup

My setup changed quite a bit since my Atrium review. Utopia and LCD-R went bye-bye and in came the Susvara to replace them both. The Atrium stayed, because I'm still deeply in love with it

• Media: Qobuz, FLAC files (Roon)
• Source: iFi NEO Stream powered by 15V iPower Elite (+ optibox)
• Headphones: Susvara, Atrium, Caldera
• DAC: Rockna Wavedream XLR Edition (I2S)
• Amps: ECP T4 (Atrium), Bakoon HPA-21 (Atrium & Caldera), Ferrum Oor + Hyspos (Susvara & Caldera)

TL;DR

Caldera are great headphones overall, but either the tuning or the timbre didn't really work for me and I didn't really connect with them the same way I connected with the Atrium (or the Verité loaner a few years ago). For someone who was never bothered by the 'Focal timbre' (in particular the Be drivers), I found the 'zingy' timbre of the Caldera quite distracting. I'm not sure if it is a driver timbre thing, or if the FR is elevated in a region of the treble I'm particularly sensitive to?

Nevertheless, I could recognize the great all-around technical performance, which I found to be a small step above Atrium overall, but not quite to Susvara level. YMMV. The one technical area where I found Caldera didn't quite match Atrium was in staging (especially depth). Mind you, they're still very good in that respect, but the Atrium and Susvara are both excellent at this. I think they are slightly more detailed than Atrium, but it's not an easy comparison because detail is not emphasized on the Atrium but it's still there (especially evident on the Bakoon HPA-21 in current mode). I found the Susvara were quite easily more detailed, though. In fact, save for impact (mostly bass), I found the Susvara to be superior all around, technically.

Bass quality combined the best parts of both the Atrium (impact / quantity) and Susvara (clarity / extension) and was a standout. I wouldn't change anything about it, to be honest.

Mids were less present than Atrium, but still more "ZMF-like" than not. I don't personally mind the upper-mid depression in the Susvara, but I know some people do and should like the Caldera better as a result.

Highs - as mentioned above - is where I had issues. As far as technical qualities (extension, speed, detail), Caldera was great overall. It wasn't painfully sharp or glarey either. "What's wrong then?", you may ask? I just felt it was trying to be "its own thing" and stood out from the rest of the FR in a way that was distracting.
Note that switching from the Noir Hybrid HPC to the stock cable (which I hated with Atrium because it muddied up everything) actually helped here. I'm now wondering if different pads could fix my issue with the treble and allow me to fully connect with the headphones and finally enjoy its superb performance...

Amp pairing

I tried all 3 amps I own with Caldera:

• ECP T4: I wasn't expecting it to work at all, but it wasn't bad at all. It's not what I would call an optimal amp for Caldera, but it's worth noting that a tube amp designed for dynamic headphones (80R and 300R headphones) didn't fall apart completely.
• Ferrum Oor (+ Hypsos): this is the amp driving my Susvara, so I knew power would not be an issue. The only thing is that I find the Oor has a slightly annoying emphasis in the mid bass with every headphones but Susvara. It offers great technical abilities and projects the largest soundstage I've heard, but clarity takes a small step back (compared to the next amp) as a result of the mid bass bump. Still, if you already own the Oor, you don't need to go out and buy another one to drive the Caldera.
• Bakoon HPA-21: in current mode, this is my favorite pairing with Caldera. The clarity is just outstanding (same as with the Atrium) and the "inner illumination" and immediacy the amp is known for is intoxicating. You'd think its tendency to shine light on all the small details would make the issue I had with treble worse, but it didn't. The only aspect of sound I liked better with the Oor was staging: the latter pushes things further out in front of you, while the Bakoon has more of a "wrap around the head" effect.

To be continued...

 

"I'm now wondering if different pads could fix my issue with the treble and allow me to fully connect with the headphones and finally enjoy its superb performance..."

We don't offer it publicly because out of the Caldera we've sold or loaned it hasn't been a complaint we've heard from more than two people, but none the less we developed a special laser cut titan mesh configuration the smooths out the peaks, which worked for the owner who requested it.

If that ends up being the case for anyone that reads this we would happily sell the same configuration for to anyone who needs it for a few bucks plus shipping. You would just want to email me. I tend to find the Titan mesh does more for the Caldera in the treble than any pad swap.

The greater majority of owners seem to find it either neutral or slightly smooth in the treble, I think it's just where the mileage varies the most in audio because of listening volume, genre choices, and age.

 

The Titan Radial mess has fixed the treble fatigue with my Grado RS1i, which speaks to the possibility that the mess may work with multiple headphones and be more effective than pad swap..

 

As always, thank you SBAF and Zach for the loaner tour.

The Caldera is not at all what I expected from ZMF's first in-house planar. I've gone on record numerous times saying that the ZMF Ori (with oval pads) is probably my favorite headphone of all time -- it's neutral, impactful, timbre is pretty much perfect. If there are flaws to be found with it: it's not the final word on resolution, it could stand to be a little smoother in its delivery, and it can lean maybe just a bit dark. ZMF's most recent headphones (that I'm familiar with) tackle some of these defecits with aplomb: the Verite Closed are bassy, slap like a mother, with oodles of smooth resolution, and addictive timbral oomph; but to me it's a romantic, dramatic approach -- not particularly neutral; the Atriums are spacious, honeyed in the mid-range, gracefully detailed up high, and nicely bassy for open-backs; but it is similarly a departure from the standard, rather than an attempt to achieve a new one. The Caldera, it turns out, is to my ear probably the most-neutral of ZMFs recent stable -- though with some caveats.

The first impressions upon listening was that it was the most un-ZMF ZMFs yet -- their sound profile is actually quite effervescent, almost 'citrusy'. (In case that's too conniseur-y: the Calderas are 'bright' but not quite sibilant or piercing, it's just got some extra edge or textural fizziness up top.) This results in what I think are the Calderas' strongest and most apparent trait: they are absolute monsters in detail & imaging. Songscapes are utterly holographic, layered yet beautifully parseable. Textures are vivid and rendered with ultrafine clarity and precision. 'Clarity' would be maybe the one noun I'd attribute to the Calderas -- even Youtube videos, like reviews or interviews, seem somehow extra-crisp via Calderas. They are airier than the VCs or Atriums, as well -- but without becoming diffuse or overly breezy.

They are not as 'refined' and 'smooth' as either the VCs or Atriums, and have slightly more serration in treble presentation than the Ori's. This does result in a perhaps brighter-than-ideal glare on certain tracks. (Radiohead's 'Airbag' set my teeth on edge, a bit.) But I imagine this to be a bit of give-and-take, where with the extra effervescence up-top comes the amazing sense of decay/reverb, and oodles of effortless detail, without any discernable veil a la the 600s/650s/800S. Timbre is also excellent, very organic and with great 'knock' -- though they sound overall 'flatter' than the VCs or Atriums, where transients have more of a thick rounded chocolatey thwack. Partially for this reason, I feel the Calderas thrive most on tracks with rich, intricate production and arrangements -- more simplistic songs can come off as a relatively flat or lacking in dynamics.

Like I said: neutral, for the most part. If there's an area I can point at and call a deviation from neutral, it'd be in the midbass. To my ear there seems to be a tad bit of recess, so that bass drums and certain space-filling components of basstone don't have quite the presence I'm used to/crave. As ever, it affects certain recordings more than others. On some tracks, the deeper-bass impact of a bass drum hit kind of blends right into the subbass of the rest of the instruments, leaving you with just a hint of bassdrum 'slap'; on other tracks it sounds pretty much typical, albeit still more subtle than other cans. Similarly with bass guitar, certain tracks you can't quite make out what is the bass guitar's contribution to the soundscape's very low end, so you can only really pick out more mid-to-high-frequency details alongside string/fret buzz and grit in the bass playing. I hesitate to call the Calderas bass-light because I don't think they are -- they have fairly decent bassy resonance and presence -- but there's a slight lack of authority in that region I'm describing that I think makes them feel, to my ear, more bass-light than they actually are. However, it's a really mild qualm, small enough that I wouldn't be surprised if a simple pad-swap could remedy that particular characteristic. (And these things are so subjective, I also wouldn't be surprised if it turns out I'm the only one with this quibble.)

I really, really, really like the Calderas. I think they're immensely impressive. If you're a detail-nut, or love to really pick apart nuances in production and recording, these are a sure bet. I don't think you can do better. For my part I will probably be eagerly anticipating a Caldera Closed, mostly just because open-backs don't seem to work well for my situation at home most of the year (wall-mounted air conditioners, yay). If I had 3.6k laying around I'd nab one in a heartbeat, just because it's addictive as hell so vividly detecting so much new textural character and little microplankton-y details on tracks that I thought I'd heard every nook and cranny on. For now I’ll twiddle my thumbs holding out for a closed version or, maaaaybe, a b-stock deal.

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Also having read some more of this thread now I think were I to get a pair I might go for that custom titan mesh @zach915m mentioned. Like I said it wasn’t an issue for me most of the time but certain tracks pushed the high-end envelope a tad for me, and I think it could stand to lose a bit of treble energy overall without detriment.

 

I was finally able to spend some time listening to Caldera driven by ecp DSHA-3F nickel in contrast to Ferrum Oor. All in all, the Oor gets out more of Caldera's almost fizzy character. With 3F, it's a more sedate story, still full of detail and depth but not as driving. For the music I listen to (lots of modern jazz, some modern classical and this and that from around the world), I think the ZMF matches are Atrium with Stellaris, Caldera with Oor, and Verité with 3F. Different moods and highlights, of course.