ZMF Caldera Closed Review

Look what the cat dragged in? (I had no idea a Caldera Closed exists until recently - I have still yet to review the Atrium Closed).



Tonally, the Caldera Closed sounds like a combination of the Massdrop Fostex TH-X00 and an Audeze. There's a hint of the TH-X00's W frequency response and this is combined with a dose of Audeze's recessed mids (not as extreme). The lows are not voluminous, but there's some solid mid-bass punch going on. Other aspects such as timbre and transients are like the Caldera Open. Suffice to say that ZMF tuning is quite different from Harmon, so you if love the Harmon target (whatever version or moving target it's up to now), best to go elsewhere.

From memory, I feel the Caldera Closed does have a better sense of heft or solidity in the lows with marginally better articulation compared to the Open version. Maybe it's the cups? Still the Caldera Closed falls in the category of "orthos for dynamics lovers". It doesn't quite have the vivid mode presentation of modern megabuck orthos (Empyrean, Susususvara, Abyss, etc.), but rather has the contrast turned down (think less macro detail and more evident microdetail) with less edge. As such, the highs are easier to deal with (particularly with pop music - using the usual tracks from Dua Lipa to test) with the timbre being more natural (not metallic or splashy). Tradeoffs. Think ortho with dynamic qualities or dynamic with ortho qualities.

Unlike the megabuck orthos, the Caldera does fantastically from entry level amps. I found the performance of the Caldera to be solid from the Magni Unity (with built in ESS DAC). This setup is agreeable match synergistically. There's no need for high current amps (the Caldera Closed is listed as 60-ohms impedance), high power amps, high gain amps (at high gain, I did have the volume knob at the 1 o'clock position on the Magni Unity). I will try with the iFi Bar Gold dongle and report back.

Below is the frequency response.

ZMF Caldera Closed
Frequency Response
Compensated to DF & 1db/octave slope


ZMF Caldera Closed -vs- Audeze LCD2C (white)
Frequency Response
Compensated to DF & 1db/octave slope

The Audeze is flatter in the lows without the midbass bump and upper bass depression. The Audeze is also much more relaxed in the highs.

ZMF Caldera Closed -vs- Caldera Open (white)
Frequency Response
Compensated to DF & 1db/octave slope

Similar highs with the Caldera Open, but the Open is flatter in the lows to the middle mids.

 

ZMF Caldera Closed
CSDs




We have have ringing (ridges) at 15kHz and extended ringing at 6.5kHz, albeit low in level. This type seems typical in many orthos. Compare to Susvara and Audeze LCD which are less controlled (dampened) and more controlled respectively.

HFM Susvara
CSD (for comparison)


Audeze LCD2C
CSD (for comparison)


Conjecture is that the narrow ridges are the result of lower tension / less damping on the diaphragm.

 

Confirmed talking about the X00. Made corrections to above.

 

I will do a full distortion surface later, but this is with 500Hz set to 100db SPL. I wanted to get a quick look.

ZMF Caldera Closed
Distortion (H2-H4) at 100db SPL (500Hz)


The results are fantastic, basically environmental noise in the lows and limits of microphone / gain for the rest. I may not bother with a distortion surface graph.

 

The Verite Closed have more microdetail, is more efficient, and a nick more lively. The Caldera Closed less microdetail, but cleaner lines and more controlled - it's a planar after all. I find the Verite Closed to scale a bit more with better upstream components. They are both ZMF headphones, so the technical (and even tonal) differences between them are not huge, say as much as between an HD600/650 vs LCD2. I mean, I could be either headphone on forget which I have on.

Both Verite Closed and Caldera Closed headphones are mid-centric with evident bass (more than measurements would suggest). The Verite Closed, especially with the soft wood cups, does have more of a middle-midrange emphasis (and woody resonance play) than the Caldera Closed.

If I have preference, it would be slight: the Verite Closed. The reasons would be as follows:

• I prefer dynamics and feel that they extract more plankton and more lively, even with modest gear like the Unity
• I am willing to sacrifice clean lows, clarity, etc. (distortion) to get the above
• The Verite Closed (with the soft wood cups) is more interpretive experience (OMG, ASR people are having a cow!). The Verite Closed is like an Audio Technica W5000 with the wonky FR toned down and much better technicalities. I don't go for ZMF headphones for neutrality or "what the artist intended*". I have JAR600 for that.
• The Verite Closed was in my top five headphones list a few years ago. It still remains so. I'm not easily seduced by the latest and greatest.
• These are my preferences. Your preferences may be different. The Caldera Closed remains a solid choice where I actually prefer it to the regular Caldera.

*That is whoever the F approved the final mix and master in the studio

 

With respect to the higher line HFM with those thin nano-diaphragms, I've decided that I cannot stand the timbre. Sure the diaphragm is thin, but those metal traces that are splatted over them are thick and probably account for most of the mass. I suspect this is the reason for their splashy timbre treble depending upon the unit. We are hearing the metal. Reminds me of these KEF aluminum drivers I heard 15 years ago which sounded like pots and pans ringing after they clank each other.

With respect to the oversmoothened ortho presentation (or lack of grain), the Caldera Closed sits between dynamics and typical orthos. This is another reason why I say the Caldera is the ortho for the dynamic fan. It an ortho that posseses a lot of dynamic headphone sensibilities. Or maybe it's a dynamic that captures some ortho sensibilities.

 

Caldera Closed Impedance


Starts off around 63-ohms, at 10k drops to 14.5-ohms and at 20k drops to 8-ohms. Not really worried at the loads in the highs. If it were the other way around (lower Z in the lows and mids), then I would be more concerned about pairing with amps. Then again, I think these concerns about "high-power, high-current" are overstated and have been for some time - read this. I mean as lot as one does not abuse. Any by abuse, I mean cranking both the volume knob on an amp and the bass knob on say a Loki EQ all the way.

 

On a related note, I did just had a chance to compare the Atrium / Verite dynamics to the Calderas on more modest amplification. I would say that in such cases (Nitsch Piety, Schiit Unity, iFi portables and dongles), the Caldera would be the choice. Stuff like Atrium and Verite really need top-notch amplification, preferably good SE tube or deep class A solid-state designs to shine.

With good amplification and source, it's a toss-up and comes down to preferences.

 

Soon. I haven't forgotten. Lots of new stuff in the ZMF line.