ZMF Headphones Caldera

Caldera's biggest strength at the drawing board was that it was designed from scratch. With a new asymmetrical magnet array working for – not against or apart from – earcup acoustics, ZMF's original work merged their two biggest technical accomplishments from 2022 into one headphone.

Certainly, CADS birthed Caldera together with the Atrium Damping System (ADS). CADS starts with trapezoidal N52 magnets that shape and optimise airflow either side of Caldera's 80mm planar driver minimising turbulence and phase issues. 

It's a volcano-like magnet structure that allows air to naturally spread out, and maintains a slightly asymmetric force making the membrane more nodal, pushing a massive amount of air towards the ear while diffusing it at the same time.

Macro dynamics are a given but it's micro-dynamic reproduction that distinguishes Caldera. The traces in proprietary ZMF planar driver film are gold-plated copper, and the diaphragm is coated with silver to maximise excursion along the traces.

It's not just sheer driver size producing authority and slam – actual pistonic excursion akin to dynamic drivers reproduces tiny gradations in SPL that sees Caldera's timbral resolution on par with the likes of its Atrium and Vérité counterparts. 

Armed with the technological potential of CADS, 2022's release of ADS was the key taking Caldera's design to 11. 

Atrium Damping minimised back-wave cancellation from the rear of the driver, for more pressure to be exerted in a controlled manner towards the ear, carefully away from the back volume at determined frequencies.

The smallest details made all the difference to a driver with as much resolution as Caldera produced, and ZMF extended their research to earpads with three depth variances released for a complete ecosystem of accessories.

All Caldera pads bear fluting – the tapering of rim thickness and circumference back to front – officially sealing the integral role oft underestimated items play on the ZMF tuning process.

Already, Caldera's combination of Atrium Damping plus the horn-like acoustic amplifier its sculpted earpads take the form of ensure substantially better SPL loading of the driver ear-side.

With sensitivity at a high 95dB ensured by these added implements, the driver and motor are then freed to focus on mustering as much deep bass extension as possible from the air volume within limited cup enclosures.

Caldera is a call to experiment with sources, so big portable music players such as Cayin Audio's N8ii and C9, HiBy Music's RS8 plus iBasso Audio's DX320 MAX TI throw their hat into the ring to work satisfactorily.

Yet for the very best performance, make use of ZMF's purely resistive, 60ohm flat impedance and electrical phase for a happy match with transformer output tube amplifiers from Cayin and Feliks Audio.

Perfect voltage sources can't hurt either and the solid-state route is straightforward with Questyle Audio's current-mode desktop flagship CMA15. The Cayin iHA-6 and HIFIMAN EF400 are absolutely capable.

And the dCS Data Conversion Systems Lina, with unlimited damping factor and resolution, finally milks every drop of performance left untapped in Caldera.

That's exactly the kind of attention Caldera deserves, the planar-magnetic cherry on the ZMF cake that completes the circle from the very first days Zach Mehrbach spent modding venerable Fostex T50RPs. Caldera is a headphone unlike any other, entering a world of planar magnetics yet not being entirely of it.

Explore the rest of ZMF's dynamic driver releases here as the perfect complement to Caldera, or check out our other headphones here.