Earsonics ONYX Review

Earsonics ONYX review featured_2

Earsonics is a French IEM manufacturer with over 20 years of experience in the audio field. In this review, I’m checking out the Earsonics ONYX earphones. The ONYX is a hybrid quad-driver IEM with 1 dynamic driver and three balanced armature drivers. It retails for 490€ (approximately US$533).

Disclaimer: This sample was provided by Earsonics for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

Earsonics ONYX Review
With a rock-solid build, low-key aesthetic and musical tuning, the ONYX is perfect for anyone looking for a warm, resolving IEM.
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Warm, inoffensive tuning
Overall resolution
Imaging and layering
Rock-solid build quality
Some people might find the shells heavy
Limited included accessories
Our Score

Earsonics ONYX

  • Sensitivity: 122 dB/mW.
  • Frequency Response: 10 Hz -20 kHz.
  • Impedance: 16.5 ohms.
  • Driver: 4 drivers (1DD+3BA) with 3 way HQ impedance corrector crossover.

Package and Accessories

The ONYX comes in an unassuming, utilitarian matte black box. Inside the box, you’ll find the Earsonics ONYX, a detachable 4-wire silver cable, 2x pairs of single-flange silicone eartips, 2x pairs of double-flanged silicone eartips, 2x pairs of foam eartips, a cleaning tool and a carrying case.

What's in the box
Earsonics ONYX design


In the age of flashy, colourful 3D-printed resin shells that we live in, I was pleasantly surprised when I first laid my eyes on the ONYX. Crafted from anodized zinc and magnesium alloy with a matte black finish, the ONYX looks something akin to a Northrop Grumman B-2 Spirit (stealth bomber).

ONYX’s contoured shells are largely unadorned except for an ES logo on the faceplates and some grooves carved into the inner side. On the top of the earpieces are standard slightly recessed 0.78mm sockets.

The nozzle diameter is slightly narrower than average. This and the fact that there’s no lip on the nozzles means that some third-party eartips fit loosely. I’ve had to fish orphaned eartips from my ears more than once as a result.

The shells are heavier than your average IEM. It doesn’t bother me in the least but some people may find it an issue. ONYX fits great in my ears, despite the shells being somewhat large. I can wear these comfortably for hours on end.

Earsonics ONYX with xDuoo Link2 Bal and iPhone

The passive noise isolation is excellent, making ONYX great for blocking outside noises. There’s virtually no noise leak either so this IEM is ideal for commuting.

Internally, ONYX houses Earsonics’ Acrylic Heart® technology which enables precise driver alignment for optimal phase control. The single dynamic driver and 3 balanced armature drivers are positioned within the heart which resides in the acoustic chamber.

Included in the box is a high-quality 4-core silver cable. The cable handles well and feels robust. It doesn’t have any significant microphonics (cable noise) and is not prone to tangling.

ONYX with Soundaware M2Pro


Gear used for testing includes the Cayin RU6, Soundaware M2Pro and iBasso DX120.

ONYX has a warm, musical presentation. It has elevated bass, full-bodied mids and an inoffensive treble. I’d say it has a safe tuning but one with strong technical capabilities. It’s a refreshing change from the recent slew of Harman target tuned IEMs. It doesn’t need extra amplification or a fancy source.

Earsonics ONYX frequency response graph
Earsonics ONYX frequency response.

ONYX gets warmth from its elevated bass. The bass lays down a velvety depth as a foundation for the entire spectrum and is unapologetically boosted north of neutral. There’s grit in the bass too, providing texture and layers in abundance.

With its medium-paced attack and fast decay, ONYX’s bass is rounded and natural yet nimble at the same time. The density of the alloy shells prevents any unruly distortion or resonance resulting in excellent control.

Sub-bass notes dig deep without blanketing the sound or bleeding into the other bands. It not only rounds out the lovely mid-bass but also adds groove and authority to the sound.


One of the challenges of tuning a warm IEM is maintaining clarity and detail in the midrange. ONYX rises to the challenge with aplomb; the mids are energetic, detailed and nuanced.

The transition from the bass to the lower mids is done just right, clearly separating male vocals and instruments while maintaining overall cohesiveness. There’s a clarity and spaciousness in the midrange belying the sense of warmth and musicality that ONYX delivers. Despite the elevated bass, vocals and the midrange, in general, are upfront and engaging.


It’s the treble tuning that does a lot of the heavy lifting when it comes to ONYX’s sound. On one hand, the treble counterbalances the fullness of the bass and brings clarity and detail to the midrange. On the other hand, the treble isn’t sibilant and is smooth enough for extended listening without fatigue.

There’s plenty of detail and energy in the highs for precision and excitement respectively. It’s smooth enough for a daily driver yet is crisp and intricate enough for more serious listening when desired.

Soundstage and Technicalities

Some of my favourite aspects of ONYX’s sound are the layering and placement. Despite its warm, musical nature ONYX has excellent resolution and instrument separation. As a result, the soundstage is uncluttered and organized, clearly defining the centre image from surrounding sounds.


FiiO FH7 ($449)
Earsonics ONYX (red) vs FiiO FH7 (grey).

The FiiO FH7 (review here) is a Penta-driver IEM with a 1DD+4BA configuration. FH7’s presentation is more aggressive and very upfront in terms of staging. ONYX is smoother and more easygoing.

The FH7 bass is faster but leaner. It has a cleaner leading edge on bass notes compared to the ONYX’s more rounded ones. The midrange on the FH7 is very forward – the overall sound signature is very linear. On the other hand, ONYX has more of a traditional V-shaped sound signature.

FH7’s lifted upper midrange can get a bit shouty at higher volume. Similarly, the treble on the FH7 is somewhat aggressive and can be strident. The ONYX has a smoother top end but is not as resolving when it comes to micro-details.

The FH7 is an IEM that many people find aggressive and tiring. In comparison, I can easily listen to the ONYX all day thanks to its warmer tone and rounder treble notes.

DUNU Studio SA6 ($549)
Earsonics ONYX (red) vs DUNU Studio SA6 (grey).

The DUNU Studio SA6 (review here) is a great example of how good an all BA IEM can sound. While the Studio SA6 is more tonally accurate and detailed, ONYX sounds more natural and forgiving.

The SA6 immediately sounds brighter than ONYX. It has less bass quantity, weight and impact. ONYX, in comparison, has a physical bass that you can feel and gives the sound an underlying warmth.

Mids are more forward and have more clarity on the SA6. The DUNU’s mids are clean and transparent while ONYX has added note weight making it more inviting albeit less detailed. Vocals on the SA6 are more articulate and really come to the forefront.

The Studio SA6 has a similar treble timbre as the ONYX but because of its leaner bass, it sounds more upfront. The DUNU is the more accurate sounding IEM but the ONYX has a warmer and more pleasing tonality.

SA6 has a wider soundstage but ONYX has superior layers of depth in front of the listener. Both IEMs have excellent resolution and instrument separation.

Closeup of the faceplate


The Earsonics ONYX is a refreshing change from what is becoming the status quo in ChiFi IEM tuning – the pursuit of the Harman curve with as little deviation as possible. Instead, ONYX is musical and fun and not afraid to throw in a dose of extra bass.

What I really like about the Earsonics ONYX is its warm, melodic presentation intertwined with strong technical performance. The fact that it’s built like a tank and dressed like a ninja only makes me like it even more. Recommended.

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