In this review, I check out the Kinera Celest Relentless 1DD + 6BA hybrid IEM. Relentless features 3D-printed ear cavities, hand-painted faceplates and a modular cable. The price is $169.

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

Kinera Celest Relentless

Specifications

Impedance: 27Ω
Sensitivity: 105dB
Connector Type: 0.78mm 2-pin
Frequency response range: 20Hz-20kHz

In the Box

• Kinera Celest Relentless IEM
• Detachable modular 0.78mm 2-pin SPC cable (3.5mm + 4.4mm plugs)
• Celest 221 Vocal eartips x 3
• Celest 608 Balanced eartips x 3
• Celest custom foam tips x 2
• Storage case
• Metal bookmark
• Cleaning brush
• User manual

Design

In typical Kinera fashion, the Celest Relentless comes with attractive hand-painted faceplates. According to Kinera, the pattern represents the feathers of the Relentless bird and the waves of the East China Sea.

The translucent 3D-printed resin shells are lightweight and have a single vent just in front of the 2-pin sockets and a lip on the nozzle to prevent the eartips from slipping off. The overall build quality is top-notch.

I found the Kinera Celest Relentless very comfortable to wear, even during prolonged listening sessions. Their ergonomic design nestles snugly into your ears, forming a secure seal that effectively blocks out ambient noise. This lets you lose yourself in your music, free from distractions.

The braided stock cable is 5N silver-plated copper. All of the cable components are polished aluminium, including the chin slider. The cable is slightly thicker than average but still handles nicely. This is a modular cable, allowing you to easily switch between the included 3.5mm and 4.4mm plugs.

Sound

Gear used for testing includes the FiiO KA17, HiBy R3 II and SMSL DO300EX. Relentless is reasonably efficient but it benefits from a bit of extra driving power. I’d recommend using a dongle DAC, DAP or headphone amplifier to get the most from it.

Relentless has a light V-shaped sound signature and has a good mix of musicality and technical ability. It has a powerful sound, compliments of its elevated bass but is balanced by a forward and light treble response.

Bass

The bass is substantial, resonating and engaging. Relentless’ lows dig deep and have a good sense of authority and power. This gives the sound an underlying richness and a thicker note size. But the extra body doesn’t cause a bloated or convoluted presentation thanks to the balanced treble tuning.

Sub-bass notes can rumble hard and the mid-bass punches with vigour. I wouldn’t quite call Relentless a basshead IEM but it leans in that direction, delivering an impactful but balanced bass response.

Midrange

The Celest Relentless has rich mids, courtesy of the enhanced mid and upper bass that add body and size to the notes. With such a tuning, there’s a risk of too much smoothing and thickness in the mids but the forwardness of the treble maintains clarity and definition, ensuring vocals and instruments remain distinct and detailed.

The midrange tuning works well for both male and female vocals. Male voices are deep and powerful while female vocals are vibrant yet still warm and inviting. Listening to London Grammar’s “Strong”, Hannah Reid’s vocals sound sultry and have a natural and realistic tonal quality. The midrange is fairly forward and intimate, blending cohesively with the bass and treble.

Treble

The treble on the Celest Relentless is tuned with an 8kHz peak, which is crucial for conveying clarity to the midrange and adding air and spaciousness. Without the enhanced treble, the overall tone would be too dark and dominated by the bass.

Although the treble is quite forward, it has a touch of warmth and roundness to it. By doing this, Kinera was able to add definition and bite to the treble while still keeping it smooth. Moreover, despite not being the most precise treble, it allows for above-average detail retrieval.

Soundstage & Technicalities

The soundstage is fairly intimate but never crowded thanks to Relentless’ instrument separation. There’s a fairly even amount of width and depth, creating a natural and rounded space. One thing that is surprising about the Relentless is its excellent detail retrieval, despite its prominent bass and thicker note size. However, the imaging suffers slightly from a touch of warmth in the treble. This warmth, while pleasant to listen to, can make the precise placement of instruments within the soundstage a little less distinct.

Comparisons

Kinera Celest PhoenixCall

The Celest PhoenixCall (review here) has a brighter tone, due predominantly to its rolled-off sub-bass. It has a slightly less enhanced presence range and upper treble compared to Relentless. The relentless is more V-shaped and dynamic. The PhoenixCall has more clarity and transparency but it’s more demanding of the listener and can cause some fatigue.

I think Relentless will be a less polarizing and more popular tuning compared to the brighter Celest PhoenixCall. The PhoenixCall isn’t as dynamic or balanced as the Relentless.

Verdict

The Kinera Celest Relentless delivers a powerful and engaging sound with a nod to bass lovers. Rich mids and a forward, detailed treble ensure vocals and instruments remain distinct. While the soundstage is intimate, the excellent detail retrieval is a surprising strength. If precise imaging is a priority, the warm treble might be a slight drawback. Overall, the Celest Relentless offers a fun and impactful listening experience and I think it’s a great option for anyone shopping in its price range.