Kiwi Ears Quartet English Review


Bass For Tasteful Mids




Construction and Design




  • 4 different tunings, all of them useful.
  • Very fun and powerful low end.
  • Full mids.
  • Treble with good descriptive capacity, although soft.
  • Good technical level.
  • Pleasant and attractive design.




  • Scene, image and separation levels are not very good.
  • They lack a bit of air and three-dimensionality.
  • They can be a little annoying on the ears over the hours.
  • Although the technical level is good, some might miss a higher level for the price.
  • As is often the case with bass-heavy sets, they may not be to everyone’s liking.
  • The zippered case is a bit narrow for the size and thickness of the capsules.


Purchase Link


Link to the Store




Kiwi Ears is a fairly new IEMS brand, although they already have a few models under their belt, some of which have already attracted the attention of reviewers and enthusiasts. The Cadenza model is a fairly inexpensive IEMS set that has received excellent reviews. The Orchestra model is an 8BA monitor, while its Lite sibling also has the same number of drivers, but costs about half as much. Finally, the model I am currently reviewing, called the Quartet, is a 2DD + 2BA, designed around a new dual-driver superbaric dynamic subwoofer. The diaphragm used is 10mm titanium, each driven independently by dual magnetic circuits. The pair of drivers is passively aligned to synchronise in phase to avoid sound wave cancellation. The dynamic drivers were crossed over by a passive low-pass network at 350 Hz to provide rich, thick bass, while the mids from 350Hz to 1 kHz were tuned to be completely flat. The Quartet features a custom BA for mid-high and a custom BA tweeter for ultra-high frequencies. These drivers were modified to match the balance of the new dynamic drivers with a ventilation system tuned to provide more airflow. In the Kiwi Ears tradition, the balanced armatures are passively adjusted to match our internal target curvature for the mids and highs. Another important aspect is that it has two mini-switches to set the sound in 4 different curves.
Well, practically all this information has been extracted from the web. But, after this introduction, I guess it will be more interesting to talk about other aspects and, above all, its sound, at least from my point of view.





  • Driver Type: 2DD 10mm + 2BA.
  • Frequency Response: 20Hz – 20kHz.
  • Sensitivity: 110dB SPL/mW.
  • Impedance: 32Ω
  • Capsule Material: Medical Grade Resin
  • THD: 0.3% THD: 0.3%
  • Jack Connector: 3.5mm SE gold plated.
  • Capsule Connection Type: 2Pin 0.78mm





The Kiwi Ears Quartet comes in a medium-sized, purple box, whose dimensions are 131x113x66mm. On the front side, a realistic photo of the capsules can be seen in the centre. A little higher, on the left, is the logo of the brand, on the right, the slogan. Below is the model name, all in white letters. On the back is the model name in very large white letters, logos of the certifications it complies with, as well as the brand’s brand name. Interestingly, the address is in Ireland and Manchester, but they are manufactured in China.
After removing the decorated outer cardboard, you see a completely black box, with a silver logo in the centre of the box. Underneath are the capsules inside a layer of foam lined with black cardboard. The model name is on the left side, while the logo is on the right side. Underneath this layer is the case with the rest of the accessories, which is black and has the logo in white. In summary, the complete contents are as follows:


  • The two capsules.
  • A zippered case.
  • One instruction manual.
  • The cable.
  • One set of black silicone tips, sizes SxMxL.
  • One set of grey silicone tips, sizes SxMxL.
  • One set of white silicone tips, sizes SxMxL.


Each set of tips comes in an individual transparent zip pouch. The zippered case is a bit wider than usual, the problem is that it is a bit flat for the volume and size of the capsules. A few foam tips and some balanced cable termination are missing. But overall, the presentation is about average for the price.



Construction and Design


The Kiwi Ears Quartet are hand-made and hand-polished from medical grade resin. The shape is almost custom, with integral nozzles. The body is thick and the resin has a flowing purple and glitter pattern on a black base. The outer face has the gold logo on the inside. It is shaped like the African continent, although more stylised at the bottom edge. On the side are the two mini-switches, while the transparent piece that houses the 2Pin connection is integrated into the capsule and does not protrude. Nearby there is a small hole. The inner side has a protrusion on its edge, as an anchor. As I said, the nozzles are integral, there is no separation of any material and the flow pattern is continuous on them. They are not very long, it is difficult to measure their size as they are made in one piece. At their base, the oval diameter is 6mm maximum, while the rim is 6.6mm, with the same shape. The tip of the nozzle is not flat and has two generous holes, which are the channels through which the sound flows. The capsules are light, soft and smooth, pleasant to the touch and to the eye.
The cable consists of 4 coiled strands of oxygen-free silver-plated copper, protected by black PVC. The connection is 2Pin 0.78mm, while the plug is 3.5mm SE. The pin sleeve is a single, black cylinder, as is the splitter piece, although shorter in length. The pin is a small black plastic cylinder with an 8-shaped hole through which the wires pass. The sleeves of the 2Pin connectors are both black cylinders, slightly bevelled at the cable entry, with two rings near the cable exit. The right channel has a red plastic base from which the two gold-plated pins come out. A blue dot indicates the polarity. On the left side, the base is transparent. There is no velcro tape to hold the cable, but there is a plastic sleeve to protect the 3.5mm SE plug.
Personally, I love the almost custom design of the capsules, although I would have opted for a cable to enhance the beauty of the whole. The eternal dilemma is present: metal or resin capsules? That doesn’t detract from the fact that the construction is still very good.



Adjustment and Ergonomics


The almost custom design may present some problems in smaller ears, while the thickness of the capsules is relatively large. The nozzles are short and the lack of a differentiated base can be a problem with tip insertion. The fit in my ears is shallow, completely adequate for the use of my home-made hybrid tips in size L. With them, the fit is very good, as is the isolation achieved. The capsules anchor well in my pinna and there is no rotation. The protrusion of the rim can get a bit annoying after a couple of hours. In this sense, the capsule is a bit short and the body does not completely jump the rim of the pinna, impinging on it and causing discomfort after a while. The fit is high and it could be used for daily outdoor use, even for the gym or running. Also, because its weight is quite light.







«The Quartet is Kiwi Ear’s answer to those who want a fun in-ear monitor that delivers all the quality bass you need. In truth, the brand’s claim is quite apt. The Quartet has two mini-switches. Switch 1 seems to affect the impedance, because it manages to limit the bass sensitivity by a difference of just over 3dB. Switch 2 modifies the mids from 1kHz. The difference achieved at 2khz is more than 2dB. All curves converge again from 4kHz onwards. So this is the frequency point from which the 4 frequency responses pivot. It is true that Kiwi Ears have aimed for a profile with an emphasis on bass-midrange. But I don’t consider the Quartet to be Bass-Head monitors, because they have put a lot of care into boosting the mids, both the first half and the high-mids and treble. They are not clearly V-shaped IEMS, but more rounded W-shaped. The presence of the bass and high-mids can be modified depending on the position of the switches. A more bass profile can be achieved with position 10, a profile more excited in clarity with 01, while profiles 11 and 00 keep a similar relationship between bass and treble, but with a change in the overall energy of the ensemble, which affects its sensitivity.
I can’t conceive of IEMS that only have bass, as much as I like it, and neglect the midrange and treble. The tunings of the Quartet may not be original, but one thing is clear: there is bass to enjoy, but also midrange and treble. And, moreover, in the right measure. But not only that, there is clarity, definition, resolution and dynamics. It is exciting to note the energy and texture of the bass, while the voices sound with a remarkable level of presence and clarity.
This is one of the first times I’ve found all the tunings of the Quartet switches to be useful. In position 01 they have a recall to my beloved Rose QT9 MK2s, but with more bite in the bass and, above all, high mids. In the 11 position they are surprisingly similar to the LetShuoer S12s, but even subtly softening the treble, one of the controversial points of the S12s. At the 00 position they have a tendency towards the Moondrop Kanas Pro, with slightly more bass-midrange and a much improved treble extension. Finally, in the more bass-heavy 01 position, the Quartets have a throwback to the controversial Hidizs MS5s with the Bass filter. So it’s no surprise that every switch position on the Quartet is thoroughly useful and enjoyable. My favourite, though, is position 11.





The two settings with the most bass are the ones with switch 1 on. While position 11 is more balanced, setting 10 attenuates the upper-mids and turns the Quartet into a somewhat darker IEMS, where the bass is emancipated above the rest of the frequencies. In this position, the amount of energy and texture of the bass is more evident and enjoyable. At position 11, the punch is a little simpler and more controlled, while at 01 there is a little more of a more rumble and rubbery feel that lingers in the room. This sensation can be both attractive and detrimental, as it can be fatiguing due to its density, darkness and space occupied within the musical spectrum. The bass is somewhat slower and this lack of ability allows it to linger in the ambience. At position 11 these imbalances are slightly corrected, the bass becomes a little tighter and more concise, but maintains a good level of energy to continue to offer a dose of fun. The texture smooths out a little, but there are combinations of sources that make the texture really pleasant, even persuasive and suggestive.
Overall, the low end is rounded and extended, with a gentle dip towards the mids, something that brings a hint of warmth, body and physicality to the early mids. The low end reaches the first mids, even though its decay is not very pronounced.
In the pure tone test, the LFOs sound powerful, with a quite perceptible roughness, the tone is somewhat coloured and more audible than sensory, but quite full from very low. Vibration at the lower end is somewhat less natural, but is quickly corrected, generating a fairly natural sound at 40Hz, with a little colour, as mentioned above.
On a technical level, position 10 suffers a little more, with the bass lines being executed in a thicker and more voluminous way, which limits the level of layering, replacing it with a higher volume. Texture and volume overlap, generating a bass with more rumble. At position 11 the lines are thinner and the ability is increased, the balance is better, the definition is improved, as well as the sensation of speed.
For my taste, I would have preferred a higher tilt towards the sub-bass, avoiding a certain level of energy in the low-mid, to make it less bloated and somewhat cleaner. But, I can’t help commenting that I really enjoy the low end of these Quartets, because, as they say, they give me the bass I want.





But, they also give me the mids I am looking for, in a set of IEMS with a noticeable bass presence. The party is never complete if the mids are off. And I have Kiwi Ears to thank for caring about this. If we look at the graph at position 11, the curve oscillates in a sub-10dB range, from 20Hz to 10kHz. There is a clear lift in the bass, but the mids are fairly flat in the first half, with emancipation varying according to the position of the switches. It is clear that switch 2 affects this area the most, but this is not the only one. It can be seen that position 11 and 00 are similar in bass, with a clear decrease in sensitivity, but with an increase in treble. But, beyond what is visible in the curves, the Quartets have completely convinced me in the mid-range. So much so that they have become my reference when listening to Amapiano. This South African-born House style is characterised by very deep bass lines, very powerful sub-bass, which contrasts with a very full presence of voices, both male and female, even combined. Treble and cymbals are usually very present and the recordings are usually clean, although somewhat excited in the mid-high range. The addition of IEMS with a lot of energy in this area becomes counterproductive. Well, the Quartets, in their 11th position, have become my best ally to reproduce this genre, because they provide richness and power in the lows and control the mid-highs, while showing very good presence in the voices and instruments, without losing sight of the details.
The male voices can’t be said to be in the front row, but I don’t find them remote. I’m satisfied with their level of presence, their slightly warmer timbre, also the physicality and body of their base, though I don’t miss detail or texture either. It’s no monster in these respects, but it does better than many other IEMS with such a present bass range. Perhaps a little more density, punch and presence can be missed in those male voices, but again I’m happy with them. With some switch settings you might gain in this respect and lose nuance and detail, some sparkle on the surface. But the balance is right, you just have to find the combination you like best. In my case it is position 11. The female voices receive a somewhat different treatment because of the ability to emphasise the mid-highs, something that can favour them in many respects. However, the energy level can be corrected, almost to taste, achieving a level of sparkle, brightness, emphasis that can border on sibilance or control it completely. Position 11 is at that limit that respects the sibilance, but perhaps not as clean and clear as you might wish, with the advantage that the bass is still powerful.
I continue to insist that the texture is remarkable in this midrange and that the level of detail, without being too explicit, is capable of delivering the minutiae of my test tracks, at a point beyond intuitive, something that is quite eloquent for a profile like this. And that must be thanks to the BA drivers, in conjunction with the tuning of the set.
What else can I say? Well, back to the beginning, I really like the relationship between the level of presence of the range, the representation of the instruments, the recreation of the voices, the level of detail, body, physicality, transparency and clarity, in relation to a lower range centred in its central part.





Both switches affect the treble. The first one, by reducing the presence of bass, gives them more prominence. While the second switch affects the mid-highs and first treble directly.
I consider that there is a good level of energy in the first part, as well as a good representation. The activation of the second switch adds an extra naturalness, while turning it off makes them drier, duller, as if lacking sparkle. In any case, the treble is controlled, almost smooth, but can be more exciting when the first switch is turned off. As well as the extension being decent, the amount of air is not very high, something that can be appreciated throughout the range, offering a sense of control and subtle nuance. This is not a critical listening headphone, though it is an enjoyable one. The ratio of power, energy, finesse, range, extension, delicacy, sparkle and brilliance is average. None of them stand out, but I don’t miss anything either. Pretty good for my pretensions in this profile.



Soundstage, Separation


The scene is quite frontal, slightly oval, there is a lateral and stereo feeling, but it is not quite a 180º scene. Depth is felt, but it is not stratified in a well-defined way, the planes are not individualised and there is a slight blending in this aspect. The ethereal feel is average and doesn’t stand out as being very voluminous, beyond the bass. This is something that affects the three-dimensionality and the recreation of the sound image. The separation is more noticeable laterally, but less in depth, not enveloping, but not flat either. But it does not stand out in this aspect. The placement of the elements is adequate, there is a good level of resolution, definition. The details are there, it offers a good descriptive feeling, but it lacks a certain spatial spark that separates and individualises them. The amount of air, sense of envelopment, level of transparency and 3D separation are simply sufficient.





Letshuoer D13


The small Letshuoer D13 with the Silver filter are in a similar price range. It is a single 13mm dynamic driver with DLC diaphragm. Their shape is very different, also differential, they are small and excellently built. Their fit is very good and they are comfortable, even better than the Quartet, more suitable for long sessions. Its metal construction does not penalise its weight and its considerably smaller volume favours it. The accessories are very good, a more adequate zipped case, a superior cable, with balanced options. In these non-sound aspects, I prefer the D13s.
In terms of sound (compared to the Quartet in position 11), the graphs seemed to reveal more similarities, but a quick switch between the two highlights the greater sensitivity of the D13s, as well as a clearer, cleaner, even brighter and more sparkling profile. I don’t glimpse darkness, comparatively speaking, and find their profile more transparent, less physical, less dense and more airy. All in all, separation is more evident, detail is more discernible and both the scene and the image are superior.
If there’s one thing the D13s excel at, it’s bass, their tuning is comparatively clean and the level of texture, power and energy are excellent. You don’t have to go Bass-Head to excel in bass and the D13s are a great example. The level of texture and descriptiveness is better on the D13s, while the Quartet’s colour is more muted. The bass is denser, also darker, slower, lingers longer in the ambience. The D13s offer a tighter, more concise and tighter punch, more speed and less decay. Perhaps, on the negative side, you can see that their timbre is not as dark.
In the mid-range, the D13s do not offer as much density and are less smooth. There is more excitement in the range, the top end is more sparkling, gaining in clarity, transparency, focus and sharpness. There is more light. The Quartets are softer, denser, though more nuanced, with more darkness and less descriptiveness. They are also calmer and more relaxed. There is a point of excitement in the mid-highs of the D13s that may be more striking, to say the least. The Quartet’s female vocals don’t rise as high, nor are they as prominent as they are in the D13s.
The D13’s treble is more linear and by starting higher, with a cleaner low end, they stand out a notch above the Quartet’s. I also see more energy from them, as well as being louder and more sparkling.
Neither are special in staging or separation, but the D13s’ greater cleanliness affects their separation, improving it, adding a better feel and distance between notes. Also, their level of detail seems more discernible. The Quartets are gentler in many respects, offering more tranquillity where the D13s can be a little more abrupt.





Continuing my search for IEMS with the best ratio of present bass to near midrange, without forgetting a defined sound, good resolution and detail, I find the Kiwi Ears Quartet. This nicely designed, pleasant and attractive model has two switches that allow you to generate 4 different tunings and all of them are useful. Each one reminds me of other IEMS I already own and like, making them a very versatile 4-in-1.
It is true that the Quartets have punch and strength in the lows, but the mids become very full, and even the highs, although soft, have a remarkable representation. They have a good level of detail, definition and resolution and their weak point is perhaps in the stage and separation section. All in all, these are IEMS in which the whole is greater than the sum of the individual parts, and that is what makes them very appreciable as an all-rounder.



Sources Used During the Analysis


  • Aune X8 XVIII Magic DAC + EarMen ST-Amp.
  • Aune M1P.
  • Tempotec March III.