Testing Methodology: Measured using Arta via IEC 711 coupler to Startech external sound card. 7-9KHz peaks may be artefacts/emphasised due to my measurement setup which I found to be the case here. Measurements besides channel balance are volume matched at 1KHz. Fit depth normalised to my best abilities to reduce coupler resonance. Still, due to these factors, my measurements may not accurately reflect the earphone or measurements taken by others. I gave the Aurum 100hrs burn-in to ensure maximum performance prior to subjective breakdown.
The Craft 6 was one of my favourite high-end monitors of 2020. Unfortunately, it was not a model I had a chance to review in detail due to unit and time limitations during the Covid outbreak that really hit boutique audio brands such as Craft Ears hard. The Aurum was an exciting prospect for the company as they turned their expertise towards bigger, more ambitious designs – I’m very glad they did. Their efforts and tenacity have paid off in the form of a monitor that is simply a pleasure to listen to. This is a beautifully balanced monitor with a tasteful sub-bass enhancement and vibrant top-octave imbuing great joie de vivre.
Fundamentally, the Aurum draws inspiration from the Six but assumes a more linear approach that enhances listenability. This involves toning down the lower-treble, improved extension on both ends and improved linearity through the upper-midrange. Peaks are slightly shifted to make for an overall more smoothly articulated, even-handed monitor with a clean sub-bass boost and nigh neutral midrange. Treble is most coloured being defined in equal parts by a mild mid-treble hump and exemplary extension and sparkle above. This cements it as a technically capable high-end IEM that lacks in neither personality nor versatility.
Every great high-end design should start with a quality low-end, and I enjoy what the company has achieved here. Its success can equally be attributed to a tasteful sub-bass boost that avoids excessive tonal colouration in addition to a quality driver. The tuning especially gives this monitor a very clean, controlled sound with excellent separation. Notes are emboldened and carry convincing size, yet they are never plump and only tinged with warmth. This also isn’t an especially aggressive monitor and the low-end isn’t what one may consider high-energy. Rather, the Aurum excels with precision whilst retaining plenty of presence to suit all genres and the majority of sonic preferences. Those expecting warmth or a sizable mid-bass whallop may be disappointed, but those wanting a dynamic monitor with excellent extension and rhythm will find that delivered in spades.
While note attack isn’t the most concise I’ve heard, it performs appropriately for the asking price which is to say, at a very high level. Combined with the sub-bass boost, the driver produces a tight slam at the very bottom with genuinely convincing volume and tactility. The mid-bass feels just a little tame by comparison but isn’t at all sucked out or overshadowed as on some monitors with a more isolated emphasis. Still, this is an IEM that biases its dynamics and definition over the most lush mid-bass texture. Notes decay on the faster side which contributes to an overall engaging and well-detailed presentation. The best DD’s such as the Final A8000 do provide another level of definition and speed yet, but the Aurum is a natural and tasteful affair. This gives it a sense of authenticity not many sub-bass biased in-ears possess.
The Six was a revealing monitor and I feared the Aurum would take this further in order to provide the impression of even greater clarity. Thankfully, this is not the case as the company’s new flagship provides a more even-handed approach that showcases excellent refinement. The bass to midrange transition is perfectly even and neutral and the midrange itself showcases a smooth, progressive tuning on top. The upper-midrange and lower-treble especially are toned down which gives it a well-defined but not especially high-clarity or immediate expression especially relative to monitors like the Soft Ears RS10 with greater 4kHz presence. However, I do still consider vocals to occupy a balanced position, and the tonality is clean and neutral seeing as the bass emphasis is contained to the sub-bass frequencies. Definition is once again excellent owing to the tuning and a technically capable BA array. The Aurum also achieves excellent long-term listenability due to its smoother articulation and uptick of density.
This means that though it is clean, it is never intense, thin or wispy. The Aurum sounds grounded and accurate whilst retaining more than convincing clarity. Vocals are natural and well-balanced between male and female. Coherence is enhanced without introducing any woolliness or upsetting transparency. Resolving power impresses equally. The RS10 is a personal staple here and benefits from a more revealing tuning. The Aurum almost meets its performance but through a notably denser and more structured voicing. In turn, its foreground isn’t as immediate with the RS10 having more delineation between its foreground and background layers. Small details also aren’t pushed forwards, however, they are present making for a similarly insightful yet more subtle listen. It is rare to come across a monitor that balances detail retrieval and listenability in such equal measure. Dub reference curves boring, but this style of tuning just works.
Most notable is the lower-treble dip which is partially responsible for the slightly smoother and more coherent nature of its midrange. However, to say that treble is lacking energy as a result, would be a misnomer. With a medium 8kHz peak (tested audibly, shifted higher due to fit depth issues with customs on my measurement rig) and raised upper-treble, the Aurum provides a vibrant over accurate treble presentation altogether. In turn, don’t expect a perfect timbre as this results in a presentation that is relatively thin if still carrying a good amount of texture with convincing decay thereafter. It is rife with energy, sparkle and shimmer that gives the monitor an overall enhanced sense of brilliance. It also distinctly lacks splashiness or brittleness owing to the smooth estat drivers and reasonable overall levels of emphasis. Some would argue that the estat drivers are overly so, lacking bite and general note definition. This isn’t the case here as Craft Ears have done a wonderful job extracting audible results from the drivers without resorting to an exceedingly inefficient overall design. On the flipside, you do indeed miss some of the initial bite provided by a good BA-based monitors.
The RS10, for instance, despite not having the most present lower-treble itself, does provide a more defined leading edge and a more detail-dense foreground in turn. The Aurum maintains the wispier presentation Sonion’s drivers have become known for, but this quality is also responsible for its lack of aggression especially considering its, otherwise, energetic tuning. The result is a sound that is appealing, gratifying but not fatiguing and the lower-treble tuning ensures no over-sharpening or sibilance. The benefit comes in the form of exemplary top-end extension and micro detail retrieval. There is real nuance to the Aurum’s performance that matches many pricier designs if falling short of the true TOTL IEMs on the market. The sense of sparkle and abundantly present micro-details make for an inspiring listen that the vast majority of IEMs couldn’t achieve simply due to technical limitation.
While Craft Ears do tout excellent expansion with their SES system, the Aurum ends up sounding a little more intimate than most high-end monitors. Width extends just beyond the head and depth is more intimate. Though it isn’t exceedingly expansive, this gives the Aurum a focused presentation with standout imaging. In particular, the monitor has very keen direction and distance projection. Layering is also one of the better performers if still shy of the best in-class. Separation is an excellent performer though a combination of a clean tuning and excellent note definition throughout. There is palpable ether surrounding most elements and small details are easy to isolate despite not being showcased through the tuning in all regions.
The Aurumn has a low 9.6 Ohm impedance and an unspecified impedance. It is less efficient than many high-end designs but not exceedingly so and achieves high volumes even from portable sources such as dongles.
Output Impedance Sensitivity
As the company’s True Load tech states, the Aurum has an essentially flat impedance curve. This means it will sound almost identical from most modern sources. While the earphones will still pick up colouration from the source, the only change due to output impedance is a slight increase in treble volume which wasn’t exceedingly noticeable to me even from the Hiby R6 with its 10-ohm output impedance. This is an excellent result that makes these IEMs a good choice for those that value a consistent sound profile from many devices.
Despite not being the most sensitive high-end IEM, I found this to be quite practical during daily use. I’m a low volume listener and appreciate the more granular volume control afforded by designs that aren’t overly sensitive. On the flipside, the Aurum also isn’t especially difficult to drive in that you’d struggle for volume on a portable source. Comparing my desktop setup to the A&K Dual DAC dongle, I found surprisingly minimal difference between the two suggesting that the Aurum isn’t overly picky about source power output. The sound was balanced, the bass dynamic and full on both. Interestingly, it was in the treble that the desktop stack pulled ahead with a noticeable jump in clarity and resolving power. For any high end IEM, a good source is something you’d strongly want to consider. The Aurum isn’t too picky but jives best with a resolving source.
Suggested Pair Ups
The Aurum is a flexible IEM in all regards. It isn’t overly sensitive and, therefore, not overly hiss prone. In addition, output impedance isn’t an issue given its mostly flat impedance curve. In addition, it doesn’t require more driving power than your average IEM so many modern portable sources will do just fine in that regard. While they do scale in terms of resolution from a high-end source, this isn’t vital for an enjoyable listening experience. As far as colouration is concerned, the Aurum is best paired with a neutral to clear source given its focus on transparency. The treble benefits from a bit more bite and in this sense something like the THX789 is a good match. Additional warmth doesn’t hamper the listening experience either. In turn, source colouration is really a matter of preference as this IEM is nicely balanced and inoffensive in all areas.