Build and Flexibility
The Pulse, like other Astral Acoustics cables, ticks all the right boxes with durability and malleability. The heat shrink implemented here provides adequate protection from the external environment whilst maintaining its ability to conform to your body’s natural movement. While the cable is chunkier than most stock cables, the Pulse’s more prominent silhouette is to be expected from its lower AWG rating. Beneficially, coiling the Pulse for stowage is a breeze. The chin-slider works as intended, staying in the final position that it’s adjusted to.
Most importantly, the Pulse does not suffer from my biggest pet peeve: the ability of low-quality cables to maintain kinks and bends for eternity. No one loves nor wants a cable that makes it difficult to store after use.
Like the rest of Astral Acoustics’ expansive catalogue, aluminium hardware with powder-coated finishing adds to the Pulse’s overall fit and finish. It’s always about attention to detail, and Astral Acoustics has left no stone unturned in the aesthetics department.
Sound Quality
Cables are like fine wines. They can complement or enhance the flavours of gastronomical creations in subtle or assertive ways. If a wine sommelier does a terrible job, counterintuitive pairings can contradict, mask, or harm the delicate taste of intricate dishes. The same rules are extrapolated to audio.
Keep in mind that cables are complementary, not revolutionary. No matter how hard you try, you cannot simply rewrite the fundamental base signature of any IEM or headphones.
We discuss how the sonic qualities of my reference IEMs are altered through these selective pairings.
Truthears Hexa
Before Pairing: The Harman Diffuse Field Target was the fashionable target-response curve that was popularised in 2019 and remains in vogue in the present day. The Truthears Hexa does little to buck the trend but rather follows it. On its own merits, the Hexa epitomises the definition of a value proposition.
Priced at $89.99, the Hexa’s base sound signature is defined by a refined and organic mid-range presentation, followed by tasteful flourishes of sub-bass decay and tastefully tamed highs. As a whole, the Hexa embodies a quasi-flat signature with a few aberrations.
Starting from the bottom-up, Hexa’s Liquid Crystal Polymer (LCP) based dynamic driver has been tasked to represent the bass registers of the entire frequency band. LCP drivers are characteristically rigid, which mitigates the presence of distortion and modal break-ups amongst the diaphragm surface, Jargon aside, this results in a taut and snappy driver, highly responsive to sudden fluctuations. Here, the Hexa’s bass response is focused more on sub-bass vibrato and less on guttural mid-bass punch.
The rest of the 3-balanced armature array is tailored towards impressive transient performance and micro dynamics in the mid-to-high frequency bands. Surprisingly, Hexa’s midrange and treble performance rivals its counterparts that are multiples in price, with impressive clarity and note definition. While it does struggle under the weight of complex instrumentation with machine-gun-like PRAT, it punches far above its price tag.
After Pairing: The Pulse spices the Hexa up a notch, accentuating the softer edges whilst filtering out rougher/coarser artefacts in its overall presentation. The Hexa’s revitalised midrange is noticeably thickened with an elevated lower-mid floor. Even harmonics are emphasised for a luscious and syrupy midrange. Note strikes situated between the upper-mids and presence regions are tighter and more spontaneous, where the Hexa manages to deftly respond to rapid changes in amplitude. The Hexa’s splashy/raspy treble is smoothened, enhancing top-down cohesion across the frequency spectrum.
The Hexa’s low-end riffs on a similar theme, with “deliberately slower” dynamics compensating for the Hexa’s conservative mid-bass presence. A lengthier decay amplifies the “fullness” of the bass. It is important to note that changes in transient performance are moderated and only detected in silent listening environments.
Separation and imaging are marginally enhanced. Minute details are brought closer to the forefront. Overall distinguishability between instruments and vocal melodies in complex passages of music appears clearer and less hazy.
The one niggling downside to this newly-minted presentation is preference-based. The brighter tonality of the Hexa’s treble might be a bane for some and a boon to others. Taming those sharper overtones might be a step in the wrong direction, depending on the listener’s novel preferences. The same rule applies to Hexa’s more restrained macro dynamic performance. Yes, the Pulse still exhibits exceptional control in Hexa’s modified presentation, but it isn’t quite clinical nor neutral for the reference camp of the audiophile hobby.
ION-4X
Before Pairing: Realistically, the ION-4X is the shining beacon in my collection; the go-to IEM for a serious-listening session. Epitomising Vietnamese excellence, the ION-4X’s base signature prioritises a distinct juxtaposition between dexterous PRAT and bottom-heavy sub-bass. Because the ION-4X utilises a passive-crossover architecture, the qualitative problems associated with impedance swings and transient smearing (timing delays etc.) are wholly sidestepped. Crescendos and instantaneous declines in amplitude are represented realistically without drop-outs in quality.
In real-world performance, distortion is kept to a minimum and the sub-divisions in the frequency band are distinct. Beneficially, the perceived distance between cues amidst the stage is enlarged, with depth and spaciousness.
After Pairing: The incisiveness of the presence range is the Achilles heel of the ION-4X. Abrupt treble-ingress is raw as it is clinical. Sharp artefacts in music present themselves as coarse and diffuse. The Pulse-ION-4X pairing neutralises those tonal quirks by raising the lower-mid floor and rounding off peaks. The midrange in the ION-4X synergises with the Pulse excellently, promoting a more equidistant between its upper-mid gumption and lower-mid thickness, albeit more focused on the latter.
The “blooming” effect of the sub-bass is boosted slightly (not that it was a prescient issue pre-Pulse pairing), deepening up the bass region’s slower dynamics for a darker flourish. However, there is a noticeable boxiness or “cabinet-like” constriction in the bass. This is both a positive and a negative, depending on the listener’s unique tastes. Lateral and Z-axis width is heightened as per Hexa’s impressions because of the noticeable improvement in micro-detail retrieval.
The only downside to this particular pairing that is worth noting is that the Pulse does pull away from the ION-4X “brighter” and unapologetically forward signature. Tonally, there are commendable improvements in all other camps, but the regression in the upper-mid presentation does alter the base signature (for better or for worse). The raspiness of the presence region, while “hot”, is as raw as it gets in terms of outright clarity. Nullifying it, even moderately, can be perceived as counter-intuitive.
The beauty of cable pairings is inherent in their subjectivity; price is not always a worthy indicator of performance, but the acquisition price of its components and the R&D that’s invested into designing it. Price notwithstanding, various cables make synergise better than others, and what is “better” is contingent on what the user hopes to attain from his/her/pairing. Personally, I think the Pulse fares favourably with the ION-4X. Others might not.
Conclusive Remarks
Henry Tik has built a cable that is perfectly tailored to the mid-range segment. Neither a race to the top nor the bottom, it is imperative that audiophile-centric brands do not wholly neglect the middle ground. While exorbitance and value are important segments in the marketplace, the “centre” is where the dollar yields the most performance gains. The Pulse is a testament to that observation.
Astral Acoustics is not trying to construct or fabricate the “perfect cable”, but they are constructing excellent cables catered to every niche in the audiophile market, where there’s something for everyone at every price range. The Pulse is the “pulse-check” of the health of the entire industry, and I’m here for it.
