Driveability
The Zero1 has a rated mechanical impedance of 16 ohms at 1kHz, which makes it a sensitive IEM easily driven by moderately powerful sources. A dongle DAC/Amp would be more than sufficient for day-to-day listening.
However, Zero 1’s assertive U-shaped signature is a formidable beast to tame when it comes down to its glaring upper registers. Thus, it is not a question of driveability but synergy across the signal path, from amplification to transducer. For instance, the Colorfly CDA-M1 dongle DAC/Amp has a fairly neutral-to-upper-mid-focused signature. Unsurprisingly, pairing it with the Zero1 exacerbates tonal inconsistencies in the upper registers, where the preponderance of uncomfortable peaks and piercing highs are commonplace.
However, the thicker lower-mid floor of the Tanchjim Space dongle DAC/Amp provides sufficient note weight and body to counteract the prominent midrange suckout in the midrange. The marginal roll-off in the top-end of the frequency band helps to ease off Zero’s glaring treble qualities, providing for a more conducive and comfortable listen.
Thus, I highly recommend pairing warmer sources to realise the Zero1’s full-sonic potential.
Comparisons
IMR Acoustics Dark Matters
Introduction
IMR Acoustics is a perplexing brand with a series of unconventional IEM releases. Founded in 2017, the titular English brand is known amongst its impassioned fanbase for its bespoke IEM releases. Every run is limited to the number of stock IMR manufactures. Once they’re gone, they’re gone.
Today, we’re examining one of his unique experimental IEMs, the Dark Matters. Featuring an 11mm Carbon Nanotube (CNT) Amorphous Diamond Like Carbon (ADLC) driver and 6mm Bone Conduction Motors, this IEM is unquestionably an innovative enigma.
Priced at $890, this eccentric IEM is going to be put to the test against the Zero1.
Sound Signature
Note: The Dark Matters comes with their proprietary tuning system, featuring a series of lower interchangeable filter nozzles and upper filters. I have opted to stick with the “neutral” combination recommended by IMR.
Generally, the Dark Matters (with the neutral tuning combination) is a gentler V-shaped signature with a voluptuous low-end and an elevated extension in the highs. However, the Dark Matter’s midrange is far more prominent in the body and in timbral realism vis-a-vis the Zero1. The lower-midrange floor has a distinct analogue-like warmth that blankets the entire frequency band without obfuscating minute microdynamic details. As such, the Dark Matters retain a more true-to-life timbre by its bone conduction motors bypassing the eardrum for a hyper-real experience.
The Dark Matter’s low-end performance is voluptuously dense in the mid-bass, with sluggish attack and slightly prolonged sub-bass decay. In these circumstances, these are different strokes for different folks. But a sluggish bass response tends to uproot the midrange. In this case, it does so mildly. Conversely, the Zero1’s planar-like incisive response favours neutrality over chamber-like warmth.
Moreover, the Dark Matter’s upper registers lack the uncompromising detail and transient performance of the AK Zero1. The AK Zero 1’s extra-wide treble extension and forward PRAT outclasses the Dark Matter’s comparably slower transients.
Interestingly, the Dark Matter’s spatial staging capabilities and imaging feature a similar out-of-head experience in terms of distance relative to the ears. Z-axis positioning and height between instruments and voicings are slightly more lifelike on the Zero1. Their separation between instruments is remarkably similar, save for the Zero1’s prioritisation of vocal forwardness.
Concluding Remarks
The AK Zero1 is Astell & Kern’s daring foray into the hypercompetitive IEM market. The Zero1’s sonic performance is exhilarating to the senses, with class-leading transient performance, treble extension and flagship mid-bass control. Unfortunately, no first release is without its flaws. Upper-mid stridency is an apparent issue, alongside middling timbral performance due to its U-shaped frequency response.
The AK Zero1, like the DAPs before it, echoes Astell & Kern’s resolute devotion to luxury audio. The AK Zero1 is a watershed debut from the South Korean titan of a brand, and I would love to explore more of what the brand has to offer in the foreseeable future.
