Disclaimer
- The reviewed IEM is a sponsored unit by Kiwi Ears. Nevertheless, all opinions are original ideas, there is zero influence from any 3rd party or external opinions.
- No EQ or filter presets were used during the entire review period.
- Sound evaluation are kept neutral and does not include 3rd party accessories (ie; eartips, cable, reversible/irreversible mods)
Introduction
Kiwi Ears, a brand particularly known for some of their hyped releases over the past few years such as the Orchestra Lite and the affordable single-DD beryllium, the Kiwi Ears Cadenza. They have made a steady progress ever since their introduction into the Chi-Fi market. Though Kiwi Ears does not often come out with a brand new Pokémon IEMs to make themselves stay relevant, their previous releases are still quite popular and remain an option among audiophiles or for those who are just starting up.
Well, that’s enough for the soft introduction because this time though, I will be reviewing their latest in-ear monitor, the Kiwi Ears KE4. As Kiwi Ears are now trying to dip their toes into the supposedly hottest tuning craze, which is the Meta or better known as JM-1 target curve. First and foremost, I would like to present my utmost thanks and gratitude to Evelyn Zhou, marketing assistant for Kiwi Ears for reaching out and sending a review unit. That said, the Kiwi Ears KE4 features a hybrid configuration, made up with a combination of two dynamic-drivers with an isobaric design, a single customized Knowles RAB-32257 for the midrange and a single Knowles RAD-33518 for high frequencies, all connected to a three-way custom-made crossover.
The Kiwi Ears KE4 retails at around US$199 when purchased through their website, though they offer an another package to include their latest, ultra-compact dongle DAC/AMP. The Kiwi Ears Allegro Mini for just another US$5. Let us not dwell any further, thus let’s continue with today’s review!
Unboxing Experience
Although, this is my first time making a review for Kiwi Ears, I have been noticing that most Kiwi Ears products are presented in a fairly simple presentation with not much bells and whistles as well as accessories. The KE4 was no difference in this case, which came in a thick booklet size packaging. The box featured a slide up/down outer cardboard layer where you can find the specifications of the IEM on the right side of the box, some information on the back and left side. As well as a render of the KE4 itself and their branding, featured on the front of the cover.
Removing the outer cardboard layer unveils a hard cardboard box that contains the IEM itself, resting on an another cardboard cutout. Moving further, you will find a basic, compact IEM case that is made out of fabric with Kiwi Ears branding on top. You will also find a copper cable for the IEM which we will talk about and a pack of eartips of what seem to be Kiwi Ears Flex that features a built-in earwax guard without interfering the sound from coming out. Apparently, this eartip can be purchase on their website or Linsoul for US$14.99. Apart from that, you will also find few pairs of nozzle filter replacement and lastly some paperwork at the bottom of the box. Personally, I the provided accessories are sufficient though some people might disagree. In other sense, I do wish Kiwi Ears should include an another pack of eartips or a nicer IEM case.
Cable
Kiwi Ears does not provide any sort of material or specification list for the stock cable that came with the KE4. That said, through my observation Kiwi Ears used a thin yet high quality pure copper for the cable, insulated with a layer of PVC shielding. However, the cable remain very supple, lightweight and resistant to tangle, apart from the ear hook which can occasionally tangle up especially when stored improperly.
Moreover, while I was browsing through Kiwi Ears website for the KE4, it seems there is only single-ended 3.5mm available for this IEM. I am not sure whether Kiwi Ears will add a balanced cable option anytime soon but from how it looks, one have to spend a bit more for aftermarket cables if they wish to opt for balanced input. Looking at the rest of the construction of the cable, such as the connector casing on both ends and Y-splitter which feels substantially heavy on the hand. I assume Kiwi Ears used alloy in this regards compared to other cables, which generally use aluminium alloy or plastic which is a much lighter for a cable.
Specifications
Driver: 2 dynamic drivers, 1 Knowles RAD-33518, 1 Customized Knowles RAB-32257
Impedance: 28 Ohms
Sensitivity: 102dB (±1dB)
Frequency Response: 20Hz-20kHz
Cable:1.2m, 4 core copper cable, 3.5mm to 2-pin (0.78mm) connection
Nozzle Diameter: 6mm
Build and Comfort
The Kiwi Ears KE4 features a 2 dynamic-driver with isobaric system and 2 balanced armatures hybrid configuration harmonized using three crossovers, encapsulated inside a featherweight and well-made resin shell. Which can be a fingerprint magnet, though it is easily cleaned. Kiwi Ears does not specify what kind or size of the dynamic driver they used for the KE4 but they did state that the balanced armatures are from Knowles, including the one that is customized exclusively for Kiwi Ears. During my observation through consumer and reviewer feedback, some of them mentioned about driver flex to the DD of the KE4. Fortunately enough, such occurrence did not appear to occur in my set. To add onto that, I could not hear any channel imbalance nor the drivers being out of phase.
The size of the KE4 was pretty similar to the likes of most Thieaudio IEMs and Hisenior Mega5-EST, hence those with smaller ears may feel it might be a tad tight to fit these in. Moreover, the diameter of the nozzle is measured at 6mm, while this is still compatible with most eartips, ones with smaller bore might be a tad too tight, affecting its practicality upon installing it. There is a vent hole for pressure relief protected by a mesh filter as well, which I am not sure if the vents affects the overall sound quality when closed.
To say that the Kiwi Ears KE4 was “simply comfortable”, would be an understatement. The KE4 essentially fits my ear like a glove smothered with premium pure butter, without pulling my earlobe or doing anything to get the appropriate adjustment (YMMV). I simply just had to align it with my ear and push it in. Added with the lightweight construction and ergonomic design, I do not feel these pulling my ears down nor create any pressure point even after wearing it for at least 2-3 hours before feeling slight stiffness. Moreover, isolation for the KE4 was excellent as well given that a proper seal is achieved, I tested by turning on my workdesk fan which runs at a measured 68.2dB at full speed using a sound level meter. The KE4 manages to block most of the noise till I could only heard a whispering hum in the background without any music playing.
Test Equipment
- Local Hi-Res files > Astell&Kern SE100 M.Chat (Linear Phase Fast Roll-off Filter)
- Tidal (Master) + Local Hi-Res files via UAPP > Sony Xperia 1 V + DSEE Ultimate (ON), Dolby Atmos (OFF)
- Tidal (Master) + Local Hi-Res files via UAPP > Sony Xperia 1 V > Venture Electronics Odo (3.5mm)
Readers may be advised that other than preference and hearing capabilities, equipment variations could also result to different opinions. Thus, those with premium and much refined equipment may yield greater results.
Power Requirements
Driving the Kiwi Ears KE4 up to its optimal performance does not take too much of an effort from any of the sources I have tested on. Whether is it via the Allegro Mini, VE Odo or even through my Sony Xperia 1 V. The high sensitivity rating of 102dB (±1dB) and low impedance at only 28 Ohms, ensures that the KE4 could run from pretty much any source as well as easy to detect any background hiss and static noises from sources. Plugging the KE4 into my Astell&Kern SE100 on 3.5mm single-ended, requires me to turn the knob up to 30-35/150 to reach my comfort level of listening volume.
Initial Impression
The Kiwi Ears KE4 has undergone burn-in phase for at least 48 hours prior to sound evaluation. Throughout the analysis, I paired up the KE4 with a neutral source, the A&K SE100 on Linear Phase Fast Roll-off Filter chosen given that it’s the most natural sounding filter compared to default. Eartips used are the blue coloured stock Kiwi Ears Flex provided in the package. Bonus test tracks used can be found down at the end of this review.
The Kiwi Ears KE4 is currently the most affordable IEM that is tuned according to the current “meta” tuning, which also known as objectively as the most “normal” tuning. This sort of tuning has gained a lot of popularity almost at instantly among the audiophile community, aided with the exposure from well-known audio reviewers. Simply put, the Kiwi Ears sounded normal.. Well, that is the end of my revie-
Hold on, I was just jesting. The KE4 sounds VERY good for the majority of people, someone who is just starting to learn and experience the Meta tuning without breaking the bank. Referring to Diagram 1.0, the KE4 is tuned almost perfect to the target when measured via the B&K 5128, mainly in the low frequencies up into the midrange. There is a slight deviation upon approaching the upper-mid followed by some peaks and dips in the treble region.
The overall sound is neutral yet engaging, equally balanced between a slightly warm with the exciting, subtle high frequencies acts as a supporting role for the midrange to shine. If I were to talk based on my personal bias, that’s leaning more towards Reference tuning. The KE4 was slightly intense primarily in the upper-mid, since I am quite sensitive to this spectrum whereby other IEMs from Kiwi Ears likewise the OG Orchestra is a lot more tolerable. I would have also prefer a tad more warmth, extension in the lower-mid and midrange. Plus, also slightly less bass by a couple 2-3dB. Well, that’s a bit of my personal comments, let’s head into sound evaluation.
Low Frequency (Bass)
In a nutshell, based on my listening for at least a week of daily usage. Low frequencies for the Kiwi Ears KE4 could be described as neutral, airy, which skews more to the leaner side, despite on paper showed that this KE4 has an almost +10dB of bass elevation. But overall, the tonality of this IEM should not be confused with cold or thin, its more to neutral-warm quite similar to a Harman neutral just enough to bring in some fun factor into the overall sound signature.
There was little texture to report in regards to sub-bass rumbles produced by the two isobaric dynamic-drivers although it does deliver an average level of airy, subwoofer-like effect. When tested using my usual track, Hollow (16 Bit Remix) – Björk. The KE4 renders decent amount of texture, which I would describe more to a fluid, smooth rumble. Rather than a groovy rumble, loaded with small nuances and details during the sub-bass drop 30-seconds entering the track. Additionally, though the KE4 performed well enough in this section, it still could not reach into the deepest part of the bass which probably due to limitation of the driver.
Moving a little bit higher into the mid and upper-bass, I could describe it as clean, fast and punchy which each bass slam produced by the isobaric dynamic-drivers resembles a tight, meaty “thump”. I could not hear any bass bleed into the lower-mid which could cause muddiness in the lower-mid. Apart from that, the bass decay was on the shorter side which can be heard through the sound of kick drums in Frogs (Live at the Majestic Theatre, Brooklyn, NY – April 1996) – Alice in Chains that ends quite abruptly after each kick.
Middle Frequency (Mid)
Into the main selling point of this IEM, I would describe the midrange for the KE4 to be forward, intensely engaging and delivered with above average resolution. Considering that the tuning focuses to highlight the upper-mid between 2k-3kHz. Tonal balance of the midrange was slightly on the warmer and richer side, sufficient enough to give a bit of warmth tint, body and lushness in the midrange that is noticeable in male vocals and stringed instruments such as guitars, violin, etc. Hence, it is not exactly reference neutral but the overall quality was certainly resulting to a tad coloured yet natural midrange. Timbre on stringed instruments were almost natural, there’s a tad “tizz” or hardness on the tail but overall I’m very impressed with the midrange experience.
Vocals produced by the custom-tailored Knowles RAB-32257 delivers a throaty, complimented with subtle texture and small nuances, followed with an overall clean, crystal clear presentation. I could not hear any haziness or the vocals being not articulated despite the slight elevation within the 300-800Hz. That said, I am very impressed with the midrange, although for my own personal listening I would prefer a lower upper-mid gain by a couple -3dB or -5dB through equalizing since in its stock form I still think the KE4 is a tad fatiguing especially after an hour or slightly more.
High Frequency (Treble)
High frequencies on the Kiwi Ears KE4 was a job well-done for Kiwi Ears. They were able to bring out the best out of the Knowles RAD-33518 to deliver as natural as possible of sound quality. I am quite familiar with since I have some full-BA IEMs that has this particular driver. In my opinion, it can be quite harsh if the driver is not tuned properly. Regardless, the Kiwi Ears KE4 does not shove a lot of details into your ears. Throughout my experience with it, the KE4 presented treble in a smooth, airy manner, without any severe peakiness although I could pick up a tad sibilant, metallic tail at the end of notes and pronunciation of “S” and “T”.
Other than that, there was average amount of treble brilliance and presence, presented by the KE4. Some may say, the treble was a bit lacking though in my opinion it is plenty sufficient. Though it was not the star of the show I this IEM, the treble somewhat provides as a supporting role for the midrange to be able to shine much further.
When compared to Harman-esque IEMs with the Meta/JM-1 tuning, I can finally sort of wrap my head about the differences between these two. Based on my comprehension, on the Meta/JM-1 tuning there is less brilliance or presence I might say in the treble without sacrificing the treble extension when compared to Harman that often times I would perceive it to be a tad harsh or edgy with an oddly cold, lean midrange.
Technicality
When speaking of technicality, the Kiwi Ears KE4 as a whole I would place it in the average list, whereby there are no absolute weak point or what I would consider as poor. Starting off, soundstaging on KE4 was average at best. Though it does have above average depth and height within the soundstage which makes it easy to separate and distinguish the layers between the different elements in a song. However, it falls slightly behind horizontally, where the soundstaging experience was still felt like it is inside our head. Spatial imaging on this IEM was fairly accurate, just a slightly blurry/dull not as pinpoint accuracy which I would have liked but I can still grasp a good sense of direction as from where an element is coming from.
Next up, detail retrieval for the KE4 was also an another aspect I would place it as average. This IEM has absolutely no issues when handling with macro-details such as loud rumbling, large textures. Such as in the track Bubbles – Yosi Horikawa, during the introduction into the track whereby there are multiple sounds of balls hitting the wooden surface. The KE4 were able to render the reverberations of the impact from the larger balls hitting the ground but were unable to do the same with smaller items. Such as marbles rolling on the ground which requires higher detail rendering capability and resolution.
Wrapping it off with the dynamic range test for the Kiwi Ears KE4 is rated at average. Utilizing the Ultimate Headphone Test – ABYSS Headphone dynamic range test as a reference. In which explained in short, a sample sound of a drum and a bell are played simultaneously as much as 7 counts, but only the sound of the bells will become quieter. Hence, from a scale of 7 counts, KE4 was able to produce an audible 5 out of 7 counts.
Comparison(s)
Hisenior Mega5-EST
Though this isn’t actually a fair comparison, considering the Mega5-EST has two units of Sonion EST drivers responsible for its treble, I did still think it is an interesting comparison due to the similar tuning. Starting off with the bass, which the Mega5-EST came out triumph against the KE4. It has better overall bass quality, far more vigorous, visceral almost kind of bass slam with a superb sub-bass reach and resolution rendering.
Midrange was a toss up between either which kind of sound you would prefer. To my ears, the Mega5-EST was a bit more neutral, slightly leaner though still remains natural and forward with above average clarity. Meanwhile, the KE4 was a tad warmer, engaging and richer due to the slight elevation in the midrange with slightly less resolution albeit shares similar forwardness and midrange clarity.
Similarly for the treble, both IEMs has its own speciality and niches which is much more obvious considering the driver difference. The Mega5-EST would give you far better detail retrieval, treble extension and technical performance with superb resolution. Meanwhile, the KE4 sounded noticeably more natural, smoother tail although it does have slightly lesser clarity, resolution and a limited treble extension. One could not go wrong in choosing either one but for my personal liking I would pick the KE4 over the Mega5-EST since I prefer a much natural presentation over pinpoint sharpness which could also translate to ear fatigue during prolonged usage.
Lastly, speaking of comfort, both of these IEMs are fairly similar in terms of the way it fits and secure in my ears. Both are comfortable to wear with similar nozzle size at 6mm, although I think the nozzle was a bit shorter on the Mega5-EST. Still, I don’t think there’s any issue with fitting most 3rd party eartips apart with the ones that come with stiff, smaller stem diameter.
Eartip Combination(s)
TRI Clarion
This eartip reduces the bass quite significantly similar to Xelastec yet it still retains good depth, airiness and naturalness without being too lean nor light. Midrange sounded smooth, less throaty and significantly much velvety though the upper-mid still occasionally triggers my sensitivity towards that frequency. Treble sounded a tad more crisp and airy, though it was still on the sibilant side which was a no surprise since this eartip was particularly known to introduce sibilant sound especially on an IEM which is already sibilant in the first place.
Azla Xelastec
Midrange sounded much distant, recessed allowing instruments and other elements in the lower-mid and 1kHz region to shine slightly. Oddly enough, the midrange and vocal sounded a lot smoother and rounded compared to stock Kiwi Ears Flex eartips. Bass was significantly reduced when pairing with the KE4, leaning towards a much leaner, less meaty bass slam but tighter, similar kind you’d get from a BA unit though much airy and natural reverberations. Higher frequencies remains the same, smooth, airy with good clarity. Soundstage was slightly more enhanced, wider with this pairing, both horizontally and depth.
E Pro EP00
This pairing performed quite similar to the stock Kiwi Ears Flex eartips albeit, the E Pro EP00 provides slightly less bass amount and heft in delivering bass slams. Midrange was on the throaty side likewise with stock eartips, though it was a tad smoother and slightly recessed. In the treble however, the EP00 somewhat degrades the overall quality of the treble, it was slightly on the splashy side and quite sibilant. However, it was not as sharp as with stock eartips.
Purchasing Links and Where to Get?
Kiwi Ears Official website;
Conclusion
Kiwi Ears has pretty much changed the landscape (though not entirely) that the Meta tuning or JM-1 tuning is achievable at an attractive and affordable price. Of course, I am well aware that US$199 can be a large sum for some demography but at this price it is the closest thing one could get without spending US$500 for something more high-end like the Hisenior Mega5-EST. Though the Mega5-EST is what I would say a proper upgrade if an individual truly likes this sort of tuning.
That said, I would recommend the Kiwi Ears KE4 if you’re someone wish to explore the new neutral tuning or even for someone who’s just starting up dipping their toes into this hobby and looking for a solid IEM that you could hold on temporarily while you’re busy looking for synergy, etc. I could see that this IEM pairs very well with a smooth, reference-like tuned with high detail retrieval capability to render small nuances source, since the KE4 was already a quite neutral-warm sounding IEM. Well, it is up to your creativity and preference though the Kiwi Ears KE4 overall was a versatile IEM to begin with. So with that, will also be the end to my review this time of the Kiwi Ears KE4, till next time!
Additional Test Tracks
Honey Suckle Rose – The Very Thought of Two 44.1kHz
Money For Nothing (Explicit) – Dire Straits 44.1kHz
A Poem Titled You – TAEYEON 44.1kHz
Anesthetize (Live) – Porcupine Tree DSD256
Vermilion – Slipknot 44.1kHz
Hunter – Björk 44.1kHz
La vaguelette (Original Game Soundtrack) – HOYO-MiX 44.1kHz
Rhythm – Jamey Haddad, Lenny White; Mark Sherman 44.1kHz
Kimigatame (When Suara Meets DSD 11.2Mhz) – Suara DSD11.2MHz
Just Coolin’ – Art Blakey 192kHz
Automatic – Hikaru Utada 44.1kHz
In My Room – Hikaru Utada 44.1kHz
Colors (Live in Studio) – Black Pumas 192kHz
Timbres – Yosi Horikawa 44.1kHz
Misguided Ghosts – Paramore 44.1kHz
