• Pair of KEFINE Klean IEM transducers.
• Stock cable
• A canvas fabric storage case.
• A pair of tuning filter nozzle (black-coloured filter).
• Three (3) pairs of balanced bore silicone ear tips of different standard sizes.
• Paperwork like instruction manual and Q.C. card

The KEFINE Klean is relatively a sensitive one that can be driven with decent sources such as smartphones, tablets and laptops. A normal gain power output will deliver an optimal performance which sounds full and sufficiently dynamic quality.

As for tonality, since this set has a detachable tuning filter nozzle feature, it offers two distinctive tonal profiles as I will indicate the following tonal description on each tuning filter nozzle.

Silver Tuning Nozzles - a mild U-shaped sound signature which also has balanced-warmish tonality, it has a more emphasis on the low and high frequencies with slight dip on the midrange.
Black Tuning Nozzles - it has a brighter U-shaped sound profile as it has more emphasis on the high frequency part while the midrange appears to have more dip across the frequency range.

(FR graph was provided by @baskingshark , credits to him)


LOWS/BASS:

SILVER FILTER

The bass quality on this setting is quite well-balanced as it has a noticeable sub bass presence and adequately textured mid bass that gives a rumbly, punchy and impactful bass response. While it has solid bass depth and texture, I don't still consider it as an ideal for bass head's preference on low frequency.

On its sub-bass depth, there's a discernable amount of reverberations and grumble from sub bass-focused instruments. The quantity mid bass texture on it conveys a firmness on its musical notation on instruments and vocals concentrated on the bass notes and it also slightly permeates across the midrange.

INSTRUMENTS:

Bass guitars - weighty and sombre sounding.
Double basses - heavy, dark and menacing sound
Kick bass drums - dark and sonorous sound.

VOCALS:

Basses - they have those deep resonating vocals to give a dark and thick sound.
Bass-baritones - full, hefty and resonating voices which have a slight dusky sound that defines this vocal type.


BLACK FILTER

Evidently, the tuning of this one appears to be more focused on sub bass presence rather than mid bass texture unlike the SILVER FILTER. It has a more rumbly, incisive and a tad cleaner bass response but it somehow penalises the mid bass texture to sound less full and less authoritative.

The sub bass presence is even more apparent as I clearly felt the rumbling and reverberations from certain instruments like synthesisers, drum machines, low tuned bass guitars and double basses. The mid bass texture appears to sound a bit leaner on its note weight that also affects the tonal colour of some bass-clef instruments and low octave male vocal types.


INSTRUMENTS:

Bass guitars - resonant with a tad hollow sounding.
Double basses - a bit mellow and rasping sound.
Kick bass drums - rumbling yet softer sounding.

VOCALS:

Basses - they still have those rumbling and resonating sounds but noticeable it has less heavier and less darker tone.
Bass-baritones - they have a resonating voice but it sounds less full and deep to give that gruffness.


MIDRANGE:

SILVER FILTER

The midrange presentation of this one is a bit slightly recessed but it provided that adequate warmth to give a full, well-bodied and a nearly natural tonal colour on vocals, especially male ones and instruments.

As I mentioned, this type of tuning will most likely benefit on most types of male vocals but some female vocals like contraltos and mezzo-sopranos will also gain on this one too. The brasses, percussives and some strings will have these organic and almost life-like sounds from this tuning filter mode.

VOCALS:

Baritones - vocals have a warm, smooth and steely sound.
Tenors - vocals sound brassy and rich which is good for spinto tenor down to heldentenors.
Countertenors - smooth, velvety and pleasant sounding.
Contraltos - rich, heavy and strong sound from their chesty vocals.
Mezzo-sopranos - smooth and velvety sounding.
Sopranos - its more of a creamy side of sound with some emotiveness which is excellent for dramatic sopranos and to some extent, spinto sopranos types.

INSTRUMENTS:

Guitars - they sound a tad warmer and a bit meaty sounding.
Cellos - mellow, sonorous and calm sounding.
Violins - full, sensuous and but rounded.
Trumpets - they sound substantial, full and round.
Trombones - powerful and round sounding with a dark tone.
Horns - they have this warm, full and resounding sound.
Piccolos - graceful, delicate but it has a less brilliant sound.
Concert flutes - they have a rich and soft sound on them.
Clarinets - warm, rich and mellow sounding.
Saxophones - they sound warm and sombre.
Snare drums - they sound hard and shuffling.
Tom-toms - they have that warm and resonant sound.
Field drums - full and sonorous sound.
Kettledrums - resonant with a hint of velvety sound.
Pianos - warm and mellow tone as it has a rich and round sound.


BLACK FILTER

It seems that it has a more noticeable dip and presents a bit more leaner midrange presentation compared to the SILVER FILTER mode. But with some changes on its tonal characteristics, they sound more transparent, crisper and quite spirited while retaining that smoothness that the other tuning filters have.

With this kind of tuning it will add some sense of spaciousness and energy on some female vocals like mezzo-sopranos and sopranos, and also on some instruments like strings and woodwinds.

VOCALS:

Baritones - they sound more lighter and also a bit more mellow but still smooth but it has a bit less warmth and richness which sounds better on light and lyric baritones.
Tenors - a bit bright, clear and a tad brassy sound which suits well with leggero and lyric types.
Countertenors - tender and a bit fiery sounding on their vocals.
Contraltos - it sounds less depth, less warmth and less darker tone as it sounds less plush and less husky from their chesty vocals.
Mezzo-sopranos - it has a golden, fiery and emotive sound.
Sopranos - they have this clear, lofty, and gleaming sound in which lyric sopranos will fare better.

INSTRUMENTS:

Guitars - balanced to a tad dry sound from their notation strings.
Cellos - lively and sensuous sounding.
Violins - stately, clear and lustrous sound.
Trumpets - full and a bit vivid sounding.
Trombones - hard and eruptive with a hint of metallic sound.
Horns - sounds velvety and resounding.
Picollos - they sound clear and brilliant.
Concert flutes - bright and silvery sounding.
Clarinets - they have a lively and brilliant sound.
Saxophones - lively and bright tone with a hint of reedy and hollow sound.
Snare drums - precise and bright sound.
Tom-toms - less warm but still resonant sounding.
Field drums - menacing and resonating sound.
Kettledrums - resonant, hollow and a bit dry sounding.
Pianos - they sound even and bright as it has clear and some brilliance on its overall sound.


HIGHS/TREBLE:

SILVER FILTER

The treble quality of this one is relatively smooth, well-balanced and even with a modest amount of air and enough sparkle on its brilliance section on this particular frequency region. The upper-mids up to the presence part is just mildly elevated just enough to give some clarity, detail and definition on vocals and attack of instruments.

I already mentioned its modest airy extension of its brilliance section and sufficient degree of its sparkle quality.

INSTRUMENTS:

Cymbals - lustrous and undulating sound.
Hi-hats - a short dull yet full tone on its distinctive chick-y sound.
Celestas - mellow and velvety sounding.
Glockenspiels - it has a lustrous sound.


BLACK FILTER

This tuning setting has a tad brighter response as it has more gleam, crisper and a tad airier treble response. The upper-mids up to presence treble section has more emphasis as it highlights the clarity and definition on vocals and instrument for better delineation on them.

On its brilliance section, it has a sufficient amount of its airy extension with an ample intensity on its sparkle.

INSTRUMENTS:

Cymbals - bright and sizzling sound.
Hi-hats - short buzzing and resonant sound.
Celestas - it has a sweet and shimmering sound.
Glockenspiels - it has brilliant and silvery sound on its key notes.


SOUNDSTAGE, IMAGING AND OTHER TECHNICALITIES:

Its perceived sound field dimensions are in between average to above-average size with a median width on its lateral span and decent height reach and good depth that it gives me a moderately roomy head stage within my aural sphere.

On its stereo imaging, this is probably its strongest point on how it pinpoints the almost exact cues of well-separated instruments and vocals in a concave-like decently layered soundscape. This is quite an impressive performance for a single dynamic set that is capable of playback some of the most complex multi-instrumental tracks that I usually tested for this testing phase without any sort of congestion.

Driver coherency of this one is quite competent; it has a notable transient response that some phasing issues and distortion are near impossible on this one. Resolution capability-wise, it has satisfactory resolving for both macro-dynamics and micro-detail retrieval as former shows solid and ample depth its note composition while latter is able to show some details and nuances like vocals ends, notation attacks and reverb tails (BLACK FILTER appears to have a more sharper definition compared to SILVER FILTER).


PEER COMPARISONS:

KEFINE DELCI AE

• Klean's predecessor and a bit more pricey, it still retains the DELCI regular's design profile.
• It has a metal-alloy shell chassis but its driver uses a composite material on its diaphragm.
• KEFINE's first model that features detachable tuning filter nozzles.
• Due to its detachable tuning nozzles, it offers U-shaped sound profiles, from warm to bright tonality.
• In SILVER TUNING, compared to Klean's it has a similar punchiness on the bass response but it has less authority and impactful but appears a bit more cleaner, a noticeable recessed midrange presentation and similar smoothness on the treble response albeit it has a bit more airy extension.
• On technical performance, both have similar performance but the DELCI AE is quite more resolving on resolution, while the Klean has better stereo imaging presentation.

SIMGOT EA500LM

• The successor of the mega-hit EA500, but it's a bit more pricey compared to the Klean.
• Like the Klean, it has a metal shell chassis but on its dynamic driver, it uses a composite material on its diaphragm.
• It has a similar quantity of inclusions like one type of silicone ear tips.
• As this IEM has a detachable nozzle system, it offers different types of sound signature with three tonal profiles in which this set makes it more versatile.
• On its RED RING BRASS nozzle setting, if it is compared with SILVER FILTER mode of the Klean, it has more rumble but less punchy bass response, a similarly warm and rich midrange but a tad more energetic on it, and a bit brighter treble response with more sparkle.
• On its technical performance, it has an average to above-average sound/speaker stage size in concave-like stereo presentation while it is quite a tad more resolving in terms of resolution capabilities.

TWISTURA D-MAJOR

• It is on the same price point with the Klean as both of them are at around US$50.
• It also has a metal alloy shell with an unusual design language but it has composite diaphragm on its 10mm dynamic driver.
• This one is pretty well-accessorised as it includes another type of ear tips and a USB-C DSP headphone amp which is an unusual inclusion.
• Like the Klean, it also has detachable nozzles with tuning filters that offer other tonal profiles, but it offers not just two but three sound profiles.
• On its BLUE RING NOZZLE settings, compared to BLACK FILTER Mode of Klean, it has tighter, less impactful bass response, a more recessed, less warmth midrange that affects the timbre of some vocals especially baritones, tenors and contraltos, and a more brighter treble which is more susceptible to sibilance and piercing sound.
• Technical performance-wise, it has a similar performance with the Klean but it has a sharper micro-detail retrieval but appears less natural sounding on timbre.

As I concluded this product assessment, KEFINE will always stick to their goal that they will deliver a refined audio product to music lovers at the best value at an affordable pricing, and Klean is indeed the core of it. The Klean is now the most affordable KEFINE product right now and its tonal performance alone will assure an engaging and pleasant listening experience among audio enthusiasts. As I mentioned, its imaging capability is one of its highlights. I am quite impressed by a single DD set like this IEM on how I was able to determine some of the spatial cues of instruments and vocals.

KEFINE Klean is now available in selected online vendors on e-commerce stores, non-affiliated link guaranteed.

LINK: https://www.linsoul.com/products/kefine-klean?srsltid=AfmBOoqjL56OE_jh8wJxTbULt3avkQSfxxPlhZ9sOsSNqND76cwcP9up

keephifi: 35% off

For more KEFINE product reviews, check out my previous product reviews links below.

● KEFINE KLANAR

● KEFINE DELCI

● KEFINE DELCI AE

SPECIFICATION:

MODEL: KEFINE DELCI
IMPEDANCE: 32Ω
SENSITIVITY: 107dB
FREQUENCY RESPONSE: 20Hz – 20KHz
CABLE LENGTH: 1.2m
PIN TYPE: 0.78 2-PIN CONNECTOR
PLUG TYPE: 3.5mm
DRIVER UNIT(S): (1) DYNAMIC DRIVER


TRACKS TESTED: ( * = 16-bit FLAC, ** = 24-bit FLAC, *'* = MQA, '*' = DSD, *'= .WAV)

Alison Krauss -When You Say Nothing At All *
Jade Wiedlin - Blue Kiss**
Led Zeppelin - When The Levee Breaks **
Mountain - Mississippi Queen *
Queen - Killer Queen **
Guns N' Roses - Patience *'*
Eric Clapton - Tears in Heaven '*'
Sergio Mendes- Never Gonna Let You Go '*'
Pearl Jam - Daughter **
Roselia - Hidamari Rhodonite *
Assassin - Fight (To Stop The Tyranny)*
Celtic Frost- Visual Aggression *
New Order - Blue Monday *
The Corrs- What Can I do (unplugged version) *
Jimi Hendrix Experience - Voodoo Child *
The Madness- Buggy Trousers *
Metallica - Motorbreath **
Mariah Carey- Always Be My Baby *
Destiny's Child - Say My Name *
Malice Mizer- Au Revoir *
Mozart - Lacrimosa *
New York Philharmonic Orchestra - Dvorak- Symphony 9 " From the New World." *
Eva Cassidy - Fields of Gold (Sting cover)*
Michael Jackson - Give In To Me *
Exciter - Violence and Force *
Diana Krall - Stop This World **
Debbie Gibson - Foolish Beat *'*
The Sisters of Mercy – Lucretia My Reflection**
Suzanne Vega – Luka **
Lauren Christy – Steep *
Ottoman Mehter - Hucum Marsi *
Diana Damrau - Mozart: Die Zauberflöte*
Type O Negative - Black No.1 *
Felix Ayo - Vivaldi: Presto **
Three Tenors - Nessum Dorma *
Mercyful Fate - Witches' Dance *


P.S.

I am not affiliated to KEFINE nor receive monetary incentives and financial gains as they provide me a review unit for an exchange of factual and sincere feedback from yours truly.

Once again, I would like to send my gratitude to Mr. Collin Yang for providing this review unit. I truly appreciate his generosity and trust towards me and other reviewers.