Kiwi Ears Airoso

Introduction

Kiwi Ears' incontinence is exaggerated. It is possibly the most prolific headphone brand of recent times. It wasn't long ago that I reviewed the KE4 and the Quintet. But since then the brand has released several large-format headphones (Division, Ellipse and Atheia), Bluetooth over-ear headphones (Aventus and Ardor), a Bluetooth OWS called Attiva, a new dongle called Allegro Pro, even 15.3mm planar IEMS, the Aether. This time, their penultimate release is a 5-driver (1DD+4BA) hybrid model called Airoso. This new model incorporates a crossover filter with physical and RC technology that guarantees a smooth and accurate response across the entire frequency range. It uses a custom dynamic driver that incorporates an LCP+PU composite diaphragm for ultra-low distortion. This driver has been designed to generate a full frequency range. In addition, four BA drivers, two for high frequencies and two for ultra-high frequencies, are included to enhance detail and aid in the accuracy and refinement of the music. The Airoso's overall construction is durable and high quality, combining high-precision CNC-machined aluminium alloy and a titanium faceplate for a solid, high-end feel while maintaining a lightweight design. This construction not only ensures durability, but also contributes to a comfortable fit, perfect for long, fatigue-free listening sessions. As usual, the Airoso comes with a 2Pin 0.78mm connection interface and the usual Airoso accessory set. Let's take a look at this new model from Kiwi Ears.



Specifications

• Driver Type: 1 DD with LCP+PU diaphragm, 4 BA.
• Frequency Response: 20Hz-20kHz.
• Sensitivity: 110 db SPL/mW.
• Impedance: 18Ω.
• Jack Connector: 3.5mm SE gold-plated.
• Cartridge Connection Type: 2Pin 0.78mm.
• Cable Length: 1.2m.
• Starting price: $129.99.

Packaging

The Kiwi Ears Airoso come in the brand's classic box, whose dimensions are contained. On this occasion its size is 117x133x49mm. On the main side you can see two real photos of the capsules seen from the outside. In the middle is the name of the model in large hollow letters. At the top left is the brand logo, at the bottom right the full model name and a short description of the drivers used. The back side repeats part of the design of the front side, to which the brand name and importers' details are added, while at the top are all the logos of the certifications that the model complies with. Once the outer carton has been removed, a black box with the brand logo in silver holographic ink can be seen. After lifting the lid you can see the capsules embedded in a black foam mould lined with dark cardboard at the top. While at the bottom is another black cardboard box that repeats the design of the lid. Inside are the accessories. The complete contents are as follows:

• The two Kiwi Ears Airoso capsules.
• A user manual.
• One black leatherette zippered case.
• One 4-strand cable with 3.5mm SE connector and 2Pin 0.78mm interface.
• Three pairs of black silicone tips sizes SxMxL.
• Three pairs of white silicone tips sizes SxMxL.
• Three pairs of grey silicone and red core tips sizes SxMxL.

The accessories are the same as those that come with the Canta model, which is priced at $89. This new one costs $40 more and doesn't come with the top cable of the Quintet or KE4 models. Kiwi Ears still doesn't offer a balanced connection. The zippered case is among the best of the accessories. Overall, it's just a little too fair for the price.



Construction and Design

The Kiwi Ears Airoso have a hybrid construction that mixes aluminium alloy and a titanium faceplate. The inner body looks like resin and the whole is very light, soft and comfortable. The outer face is shaped like an African continent with some flat faces and rounded corners. In the centre there is a rectangle with raised oval ends. It has an elongated black plate in the same shape as its continent, which bears the brand name in white letters, while next to it there is another much smaller oval rectangle, inside which there is a perforated metal grid. The outer plate is metallic grey, with a micro-sanded texture. The inner face is black, smooth and polished resin. The thickness is medium, while the connection interface is fully integrated into the surface of the capsule. It consists of a translucent plastic plate with one 0.78mm gold-plated hole each. The inner side is rounded and grows in thickness towards the metal nipples. There is a hole near the nozzles. The nozzles have a smaller diameter at the base of 5.3mm and a crown of 6.5mm, while the total length is 4. The nozzle bore is protected by a perforated metal plate.
The cable is simple, consisting of four black plastic-coated strands, fully wound together. The sleeve of the gold-plated 3.5mm plug is metallic, black and cylindrical, with a groove near the cable outlet. The cable outlet is protected by a black rubber cylinder. The splitting piece is a medium-sized black metal cylinder and the pin is a plastic ring, also black, with a double hole through it in the shape of a figure of eight. It has translucent over-ear guides and a separate black Velcro strap. The sleeves of the 2Pin 0.78mm connectors are typical metal cylinders, slightly tapered at the cable exit, with two grooves near that point. The two connectors are mounted on rectangular plastic blocks, translucent for the left channel, red for the right.
You could say that the design of the capsule, on the outside, is a bit vintage, with those grilles and the panel with the brand name. But it doesn't differ much from the Canta model even though it uses different materials.



Adjustment and Ergonomics

Again, the semi-custom shape and the hybrid construction of aluminium and titanium plate, with a smooth medical grade resin interior, achieves superior ergonomics. The capsules are a little chubby, but their size fits perfectly in my pinna. The weight is very low and does not penalise the metal content. The over-ear guides are unobtrusive. With my large foam-filled silicone tips I get improved insulation, fit and comfort. Thanks to the larger diameter of the tips, the fit is even more occlusive than with the Canta model. Sometimes the simple and conventional, tried and tested, can be the right thing to do. Kiwi Ears has made only minor variations in order not to lose one of its strengths such as comfort, ergonomics and superior fit that allow for long hours of fatigue-free, all-round use. The Kiwi Ears Airoso is a perfect model for continuous and daily use.



Sound

Profile

The Kiwi Ears Airoso have a smooth W-profile with a slight, rounded emphasis in the sub-bass, also in the upper mids and a flare in the air area. It uses a full-range dynamic driver, 2 BA drivers for the treble and another 2 BA drivers for the ultra-treble. The graphic, between 20Hz and almost 15khz, moves in a 10dB range, which already shows that this is a balanced, homogeneous and smooth profile. Even the upper mids are also rounded, while at the entry of the treble there is a slight recession, with an energy level that remains stable until the sparkle in the air zone. In this way, the upper zone also proves to be controlled, slightly nuanced, yet with enough energy to prove valuable in its own right, as well as to nourish the rest of the range with harmonics. And yes, the name Airy may be due to that clear sense of extension in the air zone that this model possesses.



Bass

The bass of the Kiwi Ears Airoso has a rounded emphasis around the sub-bass. They don't have the classic steep rise that starts from the inaudible lower range, but instead stay at a similar level of energy until they reach the mid-bass, where they begin their descent. In this way, the bass feels bigger, rounder, fuller and better represented. It has the clear depth of the sub-bass emphasis, but also the body and physicality coming from the mid-bass to give full consistency throughout the lower range. It does not possess a Bass-Heads level of energy, but falls neatly into the Bass-Lover approach, as it demonstrates a generous, noticeable and obvious power, punch and forcefulness.
The risks of a hybrid headphone with BA drivers lie in a bad low-frequency filtering of the low frequencies coming from these drivers. On the one hand, we have 4 BA drivers that are dedicated to high and very high frequencies. Thus their frequency response at low frequencies should be very low. On the other hand, the Airoso's are fitted with an RC crossover filter that is sure to mitigate or even cancel out the low frequencies coming from these BA drivers. And so it is demonstrated in the test of very low frequency pure tones, like that great electronic music group from the 90's called LFO (Low Frequency Oscillation) by the late Mark Bell. Starting with the first audible tone, the Airoso generate a sound that is light but charged with a physical and sensory part. The oscillatory rumble is practically nil, as is their sonority. It is from 25Hz onwards that it becomes more audible, maintaining the level of physical and sensory power, although offering a subtle undulatory behaviour that normalises from 30Hz onwards. The physical part and low initial loudness gives it a very realistic level of physical depth, while the sustained power level generates a powerful amount of base body. In this way, the bass has a solid, clearly physical, punchy foundation, as well as a realistic and natural physical behaviour and depth. In the translation to real music I find a faintly coloured tone, although the behaviour is very precise and concise. The bass drums are agile, full of energy, with a low level of elasticity, with a rather limited feeling of rubberiness and combined with a noticeable dryness. The mass of air it moves is high, while the speed is on a par, with a fast fade that leaves a slight aftertaste. In this way, the bass is quite dynamic, with a good deal of violence and forcefulness in the punch, but it is very tight and always under control.
In the dirty, complex and unfiltered bass test the Airoso's move like a fish in water. There's nothing unusual about the execution of a hard low end, loaded with uncontrolled sub-bass. The reproduction of these difficult passages doesn't encounter a hint of opposition and the Airoso hold the line even when the sound pressure is high. This gives an excellent sense of mastery, authority in drawing the complex bass lines, separating them from the dirty bass drums in an obvious way, maintaining the distance between the layers and not intruding into the midrange. Excellent.



Mids

My preference for mids lies in an initial zone of the central range with body, a good physical component and adequate density. I don't like thin or distant mids. But boosting this range has a clear danger, as it generates a muddy, too forward and unnatural lower midrange. The Airoso is halfway there. It's not quite full-bodied and dense enough to appease my preference, but it's not distinctly thin or lean either. On the good side, the male voices are a step behind the more immediate foreground, with a slight warmth, but plenty of clarity and a clean feel. There is very good separation between the bass, the instruments and the voices. And this is due to the warm lightness of the notes, the medium density in this first half and the measured amount of corporeal physicality. But also the high level of resolution of the ensemble, as well as the coherence of the tuning of the 5 drivers. The mids in this part are agile, dynamic, quickly executed and separate from each other. As I say, its base is limited, but the sibilant aspect is also limited, so the whole harmonic path is homogeneous, balanced and consistent. There are no peaks in the mid-range and everything is executed in a precise, concise, well delimited and sufficiently detailed manner. I emphasise again the separation of the elements of the central range, something that allows the stereo sensation, the wide sense of laterality, the instrumental and vocal positioning to be excellent, generating a quite wide stage horizontally.
In the upper mids the incidence of the BA drivers feels dry, enhancing the precision, the informative level and emitting a subtle classic timbre typical of these transducers. In this second half the tuning is more neutral and freer from that initial slightly warm tone. The amount of energy is controlled and the timbre of the female voices is very accurate, although the physical part is still on the low side. In any case, the overall presentation is very neat, highly transparent and clean, but not lacking in texture and a delicate roughness that gives it, on the one hand a high level of informativeness, and on the other a realism that enhances the musical side of the whole, the result moving between a softly analytical character, a natural and delicate refinement and a musical neutrality with a half organic component.



Treble

The Airoso's upper range is equal parts expressive and restrained in power. Yet somehow the timbre doesn't suffer at all despite starting with a limited energy level. It is clear that tuning the treble in a soft, yet extended way when it is generated by BA drivers has its advantages. On the one hand, the notes are fine enough so that the final representation is realistic, delicate, without appearing rounded or nuanced, by limiting excess bite. On the other hand, the treble retains the vitality, incisiveness, sparkle and slight crispness that is part of a canonical high range.
The Airoso manages to focus the energy in the upper range in a controlled, but explicit way, wanting to demonstrate that air is equivalent to that high and upper range, to that cleanliness and separation between the notes. And this is how their sound is demonstrated, but this characteristic has a greater incidence in the upper range, without demonstrating an eminently bright or excited sound. I consider myself a Bass-Lover and I think this attitude could be present for this range, so I think the Airoso could be an appreciated set for Treble-Lovers, because they are tuned in a sweet spot that presents a high extension, a restrained energy level, a generous amount of air, sharp, dry, informative, resolute, precise and concise notes, plus a mix of brightness, sparkle and controlled edge that maintains an expressive level of musicality, steering away from any side of shrill, piercing or overly incisive. Again, excellent for coming from BA drivers with no designation of origin beyond the brand itself.



Soundstage, Separation

There is something predominant in the sound of the Airoso and that is their level of separation. This ability is not only demonstrated in one dimension, the elements are not only distanced in width, but also in depth, even in height. This ability is generous and influential in recreating the scene. The laterality is very marked, clearly exceeding 180 degrees and placing many elements behind the head. The result is a virtue of three-dimensional recreation that is very pronounced for the price range we are in. Perhaps that small grille on the outer face can explain the sensation of openness, of the enveloping, peripheral and surrounding capacity of the music, but there is more to it than that. The level of resolution, the precision, the finesse of the notes, the physicality of the low end, all contribute to extending the scene in all directions. Although overall, the size of the soundstage is not huge, the model name carries a lot of weight in the sense of air it possesses. Similarly the level of detail presents itself, the Airoso is very expressive, informative, but possesses an analytical ability that I like to call neutral. He is very capable with macro detail, with that ability to individualise elements and give them a palpable three-dimensional distance. But it also has certain limitations when it comes to representing the tiniest micro detail in the background of the music. It is capable of being intuited, of showing it, although in a somewhat more binding way to other notes, even when the background is very clean, black and dry.
All in all, it is clear that the image and its recreation is very good, being very proficient in the positioning of the elements, instruments and vocalists, as well as its ability to individualise them in space, without the sound becoming artificial or forced, being able to maintain naturalness and realism.



Comparisons

TinHifi T5S

Some IEMS that currently cost the same as the Airoso are the TinHifi T5S. When I reviewed them in May 2024 I liked them a lot, especially for their tuning, as well as their bass quality and musicality. They have a good design, a good set of accessories and are comfortable. I prefer the design of the T5S to the Airoso, as well as their construction and cable. The magnetised white leatherette case is also very good, but for space reasons I prefer the size of the classic Airoso zippered case. As I said, the comfort of the T5S is excellent, as is the precise fit. But it is true that the Airoso have a slightly looser fit and no internal protrusions which minimises the rubbing of the IEMS against the external parts of my ears, improving comfort in the long run. The Airoso's cable falls far short of the quality, thickness, as well as the metal parts of the T5S model, although neither features a balanced connection.
Internally, the T5S uses a new-generation ultra-linear 10mm DOC diamond-diaphragm dynamic driver, while the Airoso is a 1DD+4BA hybrid. The impedance of the T5S is higher and they need more power to match the same SPL.
In terms of tuning, there is a similarity between the two models. The T5S starts with a higher sub-bass, but its descent into the midrange is more linear, with a less rounded, but very deep bass. The midrange evens out to be very similar in the second half, even the treble tuning is similar. However, the Airoso's highs differ in their drivers, creating a clear difference in their favour, as well as a greater extension and amount of air.
The bass in the T5S is a little thinner than in the Airoso, there is a different timbre that is noticeable due to the amount of upper body in the Kiwi. The Airoso's have a larger, wider low end, with more volume and a bit more punch. The T5S have a slightly rougher, textured, springier and slightly slower bass, lingering a little longer in the room and offering more of a rubbery feel. The Airoso's bass is drier, faster, more precise and more restrained. In the very low-frequency pure tone test, the T5S has a higher sub-bass and a very pure performance in this test. The Airoso's are very close to that performance, almost identical, but the higher sub-bass of the T5S gives them that advantage. The Airoso's more precise, concise, dry and fast bass outperforms the T5S in the dirty, complex and unfiltered bass test, thanks to its greater overall control. The T5S's greater bass elasticity and bounce can make the experience of playing these complex passages heavier, denser, and more loaded.
In the mid-range, the obvious difference is in the thickness of the notes. The Airoso are more delicate, thin, analytical and airy, while the T5S are more dense and cohesive. It is also worth noting that the TinHiFi lag a little behind the Kiwi in male vocals, as well as instrumentation, with a slightly darker and less prominent sound. The mids are more prominent in the Airoso, with better focus and resolution, as well as greater cleanliness, clarity and transparency. This is demonstrated in both vocals and instruments, where the ability of that three-dimensional separation and distance enhances the informative, even musical character of the T5S, which comes across as more relaxed, warmer and rounder. Without being a midrange-centric IEMS, the central range of the Airoso is more expressive, wide, informative, transparent, separated, detailed and forward than in the T5S.
In the high end there is a different tuning that provides a different timbre. The T5S start a little more relaxed and the provenance from their dynamic driver adds a greater thickness than the Airoso, which are thinner, sharper, crisper and more sparkling. While the difference in energy is not very great, the Airoso's have a brighter timbre, more even, extended energy and a better sense of air, delicacy and finesse. The treble of the T5S is somewhat more relaxed to maintain the smooth coherence of all their tuning.
The Airoso has a wider soundstage, a sound with more volume and height, more surround and separate. The notes are more individual, with that more three-dimensional separation giving better layering, positioning within the soundstage, better laterality and stereo feel. The T5S has a good level of detail, but without reaching the precision of the Airoso, with a darker background and more cleanliness between notes. It's not all bad in this respect with the TinHiFi, but their greater density, cohesiveness, musicality and warmth limit the depth separation, layer separation and definition of more explicit micro detail. While the Airoso is no monster when it comes to rendering such micro detail, its finesse, precision and delicacy puts it ahead of the pack.



Conclusion

With unbeatable productivity from Kiwi Ears, they once again present another 5-driver hybrid set. Now the driver set consists of 1DD+4BA. Persisting with the idea of naming their products with Spanish/Italian names, the Airoso sound better than their design suggests. Many of Kiwi Ears' IEMS designs are somewhat relaxed, not too remarkable. But they are very functional. The Airoso's stand out for their low weight, great comfort and a certain degree of freedom of fit. In terms of accessories, it repeats a level very similar to that of other cheaper models of the same brand, falling somewhat short qualitatively speaking in this aspect. But best of all, Kiwi Ears continues to maintain a high level of sound in this price range. The Airoso have a tuning that I like in a controlled W shape, with a more extended, voluminous, fast, concise, agile and dry bass, with a sufficient amount of energy to generate weight and strength in the sound, as well as an excellent ability throughout the lower range. In the middle range, the informative, expressive, finesse and delicacy of the notes reproduced by the Airoso begins to come to the fore. The three-dimensional distance between these notes refers to the name of the model, breathing air around them. The mids are delicate and musical, with good presence, despite their somewhat lean representation, within a level of neutrality, great transparency, clarity and luminosity. All this is exposed one step further in the upper range. Fine-tuned by means of an energy reduction that extends into the air zone, the sound quality of the BA drivers generates an advantage in timbre, edge, sparkle and brilliance. Uniformity in extension maintains control and produces a clear, coherent timbre that stands out and supports the other strips. The Airoso's excellent level of separation makes them stand out on stage, with great laterality, height, depth and a certain enveloping character that makes the positioning of the elements obvious, marked and evident. It may not be the best at anything in particular, but all the sound scores are somewhere between a high mark and excellent, which says a lot for a model in its price range. But one thing is also clear: its name does give clues about its sound.



Sources Used During the Analysis

• iFi GO bar Kensei.
• EPZ TP50.
• Aune M1p.
• Tempotec V3.
• EarMen Angel.
• Burson Audio Playmate 2.
• Aune X8 XVIII Magic DAC + EarMen ST-Amp.

Purchase Link



You can read the full review in Spanish here

Kiwi Ears Airoso



Introduction & Disclaimer

Kiwi Ears is steam-rolling into 2025 with an almost continuous stream of new releases.
Just above the budget segment, the Airoso is placed into one of the most competitive corners of the market at around 125 Euros.

This sample was provided by Kiwi Ears in exchange for my thoughts.

For the watchers:


Further info and specs can be found here (non affiliate link) - https://kiwiears.com/products/kiwi-ears-airoso

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Build, Design & Ergonomics

Kiwi Ears have opted for an understated design approach for the Airoso, with an aluminium and titanium alloy faceplate over what look like a resin shells.
The shape of the shells is more generic, so in theory it should fit a wider range of ear shapes. There are two vents, one on the faceplate and one small one on the ear-side near the nozzle, which is on the large side at 6.5mm in diameter.

The Airoso joins the short list of Kiwi Ears products to have the simpler version of their logo without the sunburst design, which gives these a bit more of a serious vibe.



Inside is a single dynamic driver kept company by 4 balanced armature drivers.
I think this makes it one of the few 5-driver IEMs under 150 Euro, but of course, implementation and tuning is more important than driver count.

I had no specific problem with the fit and could default to my usual choice of large tips, but I didn’t find the fit particularly solid either.

Generally I do like the cable that is paired with the Airoso, it’s pliable and does a good job of resisting tangling despite being a 4-core tight twisted cable, however, aside from the slightly different hardware, it appears to be the exact same cable that is bundled with the KBEAR KB02, at less than half the price and also pales quite badly against some other thicker, higher quality cables in this price bracket.

Also bundled with the Airoso is the new Kiwi Ears carry case, which is an improvement over the original, but still nothing to write poetry about.

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The Sound

I think it’s time to briefly mention my relationship with IEMs.

I think most of them up until around 2023 were not good enough to convince me to switch from closed-back headphones as my go-to portable listening device and most of the IEMs I’ve owned or heard before then were either just awful or flawed in various ways that always made me feel relieved to go back to headphones.

Too many IEMs from many brands were pushing weird frequency responses, many with ridiculously excessive pinna-gain around 3-4KHz, and the vast majority of IEMs even today have bad imaging or below average soundstage.

We’re now entering a time in personal audio history where it makes more sense to use IEMs all year round than closed-back headphones. You no longer need to spend many hundreds or thousands to get objectively high quality sound, and the Airoso is one of those rare IEMs that sounds almost just right to me out of the box.

Sometimes I’m happy to sacrifice objective detail as long as other facets of the acoustic design make up for the deficit.
The Airoso is one such IEM.



I’m not blown away by detail, or extensive treble air, but what it lacks there is makes up for with it’s slightly reigned in pinna-gain, and the dynamic driver pushes the mid-bass just a little north of neutral and slightly more over the sub-bass.

The overall sound is slightly W-shaped with a small emphasis on lower-bass, the biggest emphasis is on the vocal midrange around 1KHz, and the pinna-gain region around 3KHz, and finally the treble gives just about enough from 8-12KHz that it still sounds moderately detailed, but it does not extend too well and cliff-dives above 14KHz.

(miniDSP EARS exaggerates treble between 8-12KHz - the spike is more like a shelf (cut it in half))


Thankfully, the blend of dynamic and balanced armature drivers is done very well only the slightest disharmony of timbres and speeds.

Ultimately it’s up to you to decide whether or not you like that mix of timbres or not. Personally I don’t hate it at all and have found that many of the recent multiple-driver IEMs, including the Airoso are implementing these mixes with a mostly homogenous sound.

While it is present, the sub-bass remains the weakest part of the performance in both presence and quality, so don’t expect minor miracles from EQ’ing a bass boost.
This is one of those times where what you hear is what you get; it simply can’t do the kind of bass you can EQ out of the KE4 or HA-FXZ200 for example.

Finally imaging is well above average with excellent positional qualities that also works really well in 3D video games, however the soundstage is about average.

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Comparisons

I want to do a fair broad spread of comparisons for this review, because it can be difficult to accurately describe and place an IEM that has such a mild and common personality.

Simgot SuperMix4
The treble is more forward and detailed with a deeper sub-bass kick; essentially these have a U-shaped signature by comparison.

Simgot EA500LM
Surprisingly very similar overall, but the Airoso has a feather touch more weight in the lower notes and more splash in the treble, so a bit more V-shaped than the EA500LM.

Kiwi Ears Aether
This is much more neutral/warm and controlled overall with a bigger staging. It makes the Airoso treble sound obviously splashier than it should be.
It is objectively the best IEM in the bunch here so that shouldn’t come as any surprise.

Kiwi Ears KE4
This has less shimmer in treble, deeper, more textured bass, and has the warmest, smoothest sound of the bunch, although the upper treble is a touch thin and tizzy in timbre while remaining soft in general.

Compared to the whole bunch, the Airoso has what appears to be a slightly v-shaped signature, with emphasis on the pinna-gain and low and mid-treble.
The Airoso was also above average in ergonomics and ease to put on.

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Conclusions

All things considered, the Airoso gets a soft recommendation.
Within the price range it does some things better and some things worse than the competition.

If you’re having trouble finding good ergonomics with more vertical shaped IEMs like the EA500LM, these more horizontal shaped shells might be an improvement.
If you’re averse to full metal shells, then the plastic might be more comfortable, especially in cold weather.

It may sound like I’m struggling to find good reasons to recommend this, but the reality is that it really doesn’t do much wrong and mostly justifies it’s price considering the effort that has gone into the sound quality and tuning.

To sum things up, the accessories are below average but the ergonomics and tuning can make up for most of it.
It doesn’t stand out of the crowd, but doesn’t get eclipsed by it’s direct peers either.

I think for anyone who actually enjoys a little bit of pinna-gain, these might be a very strong option if you want just a touch of v-shape to the sound.

Spoiler: A little about myself and my musical taste.

Hello, and thanks for taking the time to read my review. I really appreciate it!
I’m Vlad, a former semi-pro FPS player, mainly in CS:GO, and now an audiophile and reviewer of audio devices.
My passion for music started with a classic Japanese Panasonic boombox. Later, I got my first headphones - Koss Porta Pro, which I absolutely loved. I spent years listening to music on those and the Sennheiser CX200. Back then, my playlists were filled with Linkin Park, DMX, Dr. Dre, and Eminem. Hip-hop and rap captivated me, especially the deep, rumbling bass and the distinct rap-style delivery.
Now, I consider myself a music enthusiast who enjoys a wide range of genres, from metal to classical music, choosing what to listen to based purely on my mood.
When it comes to sound, I prefer a neutral-warm V-shaped tuning. I appreciate a rumbling, well-defined bass and would consider myself more of a basshead than a treblehead. In the midrange, I have a particular fondness for male vocals, as I find them the most engaging and essential in modern music. What do I dislike? Harsh treble, a lack of bass, and a narrow soundstage.

You can learn more about me in my portfolio

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• 1DD + 4BA Driver Configuration;
• Impedance: 15Ω ±1Ω;
• Sensitivity: 105dB;
• Frequency response range: 20Hz - 20kHz;
• Connector: 2 pin 0.78mm.;
• Cable material: High-quality oxygen-free silver-plated copper cable, length 1.2m;
• Price:130$.

• IEM itself - Kiwi Ears Airoso;
• 2-strand high-quality oxygen-free silver-plated copper cable, 1.2m length;
• 3 sets, 8 pairs of eartips: 3 pairs of white transparent eartips with standard bore (S / M / L), 3 pairs of gray eartips with red bore (S / M / L), 3 pairs of black eartips with standart bore (S / M / L);
• Carrying case;
• User manual.

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An airy lightweight IEM with a knockout sound​

The Kiwi Ears Airoso is a new entry in the mid-tier IEM market, featuring a hybrid driver setup with a custom dynamic driver and four balanced armatures all in a very comfortable and lightweight package.

Because Kiwi Ears have released some of my favourite IEMs in the past few years, especially the Orchestra Lite and the KE4, I was delighted with the opportunity to try the Airoso.

So, having listened to the Airoso for a few weeks now, there are many things I really like about the Airoso including its comfort but especially that the tuning is a subtle twist on some familiar tuning targets, but to find out if you should add it to your collection, please read on.
Let’s start with the unboxing:

Unboxing and Build Quality​

The unboxing experience of the Kiwi Ears Airoso is simple yet elegant, reflecting its premium-tier status:

Though not that much information on the back:


Sliding it out of its sleeve reveals the box:


Opening the box we finally we see the Airoso:


The carry case is a nice upgrade on some previous Kiwiears cases I received with a more premium texture:

And you get a good selection of eartips in 3 bags - though mostly these are fairly generic eartips:


I used my own eartips for the majority of my listening tests, but I did do my measurements of the Airoso with a medium-sized stock eartips.

Cable​

The detachable cable is of decent quality, though not outstanding. While it’s lightweight and functional it does tangle a little too easily:

The 2-pin connectors ensure easy cable updates though I actually prefer recessed 2-pin connections for extra security:

The IEMs​

The Airoso’s shell is small and exceptionally lightweight, making it one of the most comfortable IEMs I’ve worn for extended listening sessions, here is a little video showing the Airoso from all angles:

The CNC aluminum alloy and titanium faceplate give it a high-end feel while maintaining durability.

The nozzles are medium-sized and have a good angle at least for me, ensuring a very secure fit even when out walking:


They are also a good length, some IEM’s like the Truthear Zero family are very long and not always that comfortable:

Here are some comparison photos and videos - first with the Kiwi ears KE4, Orchestra Lite, the new Truthear Zero Blue 2 and the smaller FiiO FD15 - hopefully this shows with the Airoso, Kiwi ears went for good compromise of size (and it is lightest of these IEMs):

Some photo comparisons - the Airoso is on the right :


And just with the larger IEMs:


A close comparison with the other 2 Kiwi ears IEMs:

And finally a comparison with the Truthear Zero Blue 2:

So, comfort is a strong point of the Airoso, and I had no issues with long listening sessions.

Sound Impressions​

So “Airoso” is a Spanish and Italian word that translates to “airy”, “graceful”, or “melodious” in English. It is often used in musical contexts to describe something flowing, expressive, and elegant, and these descriptions align extremely well with the tuning philosophy of the Kiwi Ears Airoso providing a spacious, detailed, and well-balanced sound.
That name might make you feel the Airoso has limited bass but that would be the wrong assumption this IEM has exceptional sub-bass extension as well as that airy upper treble textures that the name implies, though I never found the treble to be sibilant.

Bass​

The bass is deep, textured, and well-extended, thanks to the custom dynamic driver with an LCP+PU composite diaphragm. It delivers a satisfying low-end punch without overwhelming the mids. Compared to the KE4, the Airoso offers a slightly more powerful sub-bass response, while the Orchestra Lite leans towards a more neutral presentation.

Mids​

The midrange is clear and natural, though slightly recessed due to the V-shaped tuning. Vocals come through with good presence, and instruments retain a realistic tonality. Compared to the FiiO FD15, the Airoso maintains better balance, ensuring mids are not overly overshadowed by the bass.

Treble​

The four balanced armature drivers shine in the high frequencies, offering excellent detail retrieval and an airy presentation. The treble is crisp and extended but never harsh, making it a more refined option than the Truthear Zero Blue 2, which can sometimes exhibit sharpness in the highs.

Soundstage and Imaging​

The Airoso’s soundstage is wider than expected for an IEM in this price range. Imaging is precise, with a strong sense of instrument separation. While the Orchestra Lite may have a slightly more spacious presentation, the Airoso holds its own with strong spatial cues.

Specifications and Measurements​

Frequency Response​

The Airoso has in my opinion a very nice tuning which mostly Harman but with 2 nice twists:

The slightly warmer bass is very typical of the new “JM-1 with bass boost” still tuning as is the slightly darker treble in the 4-6Khz region. The only thing possible worth considering might be that “airy” upper treble peak.
If that peak is too much for you, swapping to Foam eartips alters that treble region for the better:

I thought it was worth a little comparison and analyse between 2 of my favourite IEMs from last year, the “JM-1” / “New Meta” favourite the KE4 and the nicely tuned Harman Meze Alba :


I marked a few areas of interest:

1. They all have similar sub-bass and bass
2. The KE4 has a now typical JM-1 recessed midrange
3. The Alba has a more typical Harman presence in this region
4. The Airoso as I mentioned earlier possible has a treble peak (measurements in this region are never accurate to you may not hear a peak)

These frequency response graphs I hope show what a nice twist on a “modern” tuning you get with the Airoso.

Distortion​

The Airoso maintains low distortion levels across all frequencies, showcasing its high-quality crossover implementation and driver design.

And from a percentage minimal distortion:

Rating​

I am giving the Kiwi Ears Airoso a 5-star pragmatic rating due to its exceptional comfort, superb bass, and detailed treble performance especially at its price point. I like how Kiwi Ears have filled their line-up with good alternative tunings and the Airoso fits that exactly, it is not Harman 2019 tuned and not “JM-1” but something very pleasing in between those targets and a very good addition to Kiwi Ears lineup.

Conclusion​

The Kiwi Ears Airoso is an outstanding choice for those seeking a mildly V-shaped tuning with deep bass, some warmth, very decent midrange and clear highs, all in a very comfortable lightweight design. With a well-executed hybrid driver setup and excellent build quality, it’s a solid recommendation for audiophiles and casual listeners alike.

Kiwi Ears Airoso Review​

Full Review can also be found HERE

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Kiwi Ears Airoso Review​

Intro ​

Hello everyone, this review and feature covers one of the latest iems to come from the good people over at Kiwi Ears named… the Kiwi Ears Airoso ($129). The Airoso comes in with an MSRP of right around $129 (as low as $89 on Amazon US) and comes equipped with five drivers in total. To be exact, the Airoso is a hybrid iem which houses one dynamic driver and four balanced armature drivers. However, I will cover all of that within the review at much greater depth and with a fully entrenched opinion. The truth is, I write these “Intros” (usually) before I even receive the product. It helps with time as my reviews are already very long. The Airoso will be with me in about two days. I’m quite pumped for that. Kiwi Ears is one of those brands which always seems to intrigue me. I always want to know what they’re up to. Please trust, I don’t have that feeling for every brand out there. I simply trust that Kiwi Ears aren’t going to simply bring to market a rinse & repeat copycat tuned iem. Looking up the name “Airoso”, it’s basically a Spanish word meaning “Airy”. I wonder if the namesake of this set has anything to do with the tuning?

Kiwi Ears​

So, no doubt I have reason to feel “pumped-up” about this release. However, in general, name a Kiwi Ears product which simply failed. Ya know what, I’ll take this one… Kiwi Ears has yet to make a garbage product. This doesn’t mean that you like and enjoy every product they’ve made. What it means is that at least a large segment of the audio community enjoys their products. I think I can say that with good conviction. Kiwi Ears is just one of those brands which simply gets my juices flowing (so to speak). There’s a few of those types of brands out there, but what Kiwi Ears does is they aren’t afraid to try new things, and they add their own certain ‘spin’ to every product that they create. Basically, a Kiwi Ears product is most definitely… a Kiwi Ears product. A very unique brand and I think we are all fortunate that they have a good foothold in the business.

Quick success​

The crazy thing is that Kiwi Ears is not an old brand. In the realm of the audio landscape at large, they’re actually relatively new. Which is wild. I suppose that kind of puts their journey into focus a little bit. I mean, look at some of the successes that they’ve had! Truly monumental smash hits like the Kiwi Ears Cadenza (Cadenza Review), or the amazingly wonderful ‘timbre-King’, the Kiwi Ears Orchestra Lite (Orchestra Lite Review), the Kiwi Ears Quintet, the Kiwi Ears Quartet (Mahir’s Quartet Review), the Kiwi Ears Melody, the truly wonderful Kiwi Ears KE4 (KE4 Review) too. Among many others. I didn’t even mention the success of the Kiwi Ears Allegro or the Kiwi Ears Allegro Mini. Shoot, I am about to drop a review of the Kiwi Ears Allegro Pro in a few weeks and it’s great. The point is, if it’s a Kiwi Ears product, then it’ll be unique and very well done from front to back.

Competition​

Well, I just received the Airoso, and I can confirm right now that it is a very solid set. Knowing that it’ll cost around $129 US shows me that it should be one of the sets at least considered for everyone’s short list within this range. It’s that nice. Now, I’m not giving this set a free pass because there is too much competition to ever do that. We are talking over $100 and its bananas how many truly awesome iems there are in that range. Especially between $100 to $150. Just phenomenal iems. Think about it. The Airoso has to compete with the Simgot SuperMix 4 (SM4 Review), the Fiio FD15 (FD15 Review), the Hiby Yacht 10 (Yacht 10 Review), Dunu Kima 2 (Kima 2 Review), Celest Relentless (Relentless Review), the KZ Sonata (Sonata Review), the BQEYZ Cloud (Cloud Review), the Aful Explorer (Explorer Review), the Hidizs MP145 (MP145 Review), the CCA Hydro (Hydro Review) and that’s just a few. In truth, that list can go on for miles. So no, the Airoso doesn’t get a pass. Despite that comment, no doubt this is a solid set, and I repeat, you should probably put it on your short list. With all that said, I will now send the Airoso to the burn-in station for a few full days and then begin critical listening. Okay, well I think I’m ready to dive in folks. So, without further ado, the Kiwi Ears Airoso…

Non-Affiliated Purchasing Links:​

–Kiwi Ears

–Amazon

–Linsoul

–Aliexpress

Disclaimer:​

I received the Kiwi Ears Airoso from Kiwi Ears as a review sample and in exchange I will conduct a full review and feature at Mobileaudiophile.com. I have not received any payment or any other form of compensation for this review. This set is a review sample iem. Kiwi Ears has not requested to pre-read any review and doesn’t have any control over “what” or “when” anything gets published to mobileaudiophile.com. All thoughts within this review are my own, though please take note that I will always have my own biases. This is impossible to get around. I try to be as objective as my subjective self can be. However, this is an opinion piece folks. Thank you to Kiwi Ears, and thanks for reading.

Gear used for testing ​

–Ifi Go Blu

–EPZ TP50

–Kiwi Ears Allegro Pro

–Aful SnowyNight

–Shanling H0

–Fiio Q15

–Fiio JM21

–iBasso DX240 with Amp8 MK2

–Shanling M6 Ultra

Packaging / Accessories ​

Unboxing​

The Kiwi Ears Airoso arrived at my home in a fairly small square box predominantly a shade of purple with a picture of the Airoso on the front. Pretty standard but also, not bad Kiwi Ears. I like the name “Airoso” maneuvering between the pictures of the Airoso on the cover. The Kiwi Ears logo is well highlighted at the top left of the box. They are simply nice touches. Anyways, open the box and you’ll see the Airoso chilling in foam cut-outs. Next to the foam piece you’ll find a small black box with the Kiwi Ears logo imprinted on it. Open that box and inside it holds the carrying case. Inside of the case you’ll find three small baggies holding the eartips and you’ll also find the cable. In all honesty, the packaging is pretty standard fare. I wouldn’t say it’s the best unboxing experience in the price point, but also, I don’t buy any iem for the unboxing experience.

Eartips ​

Kiwi Ears was pretty generous with their eartips that they provide. In total you get nine pairs of eartips over three different styles. I’d say they are fairly useful which is much better than I’m used to. Usually, the eartips are a far-off afterthought. At any rate, there are three sets of three. The first set of three (S M, L) is a black silicone eartip with a semi-wide bore. These tips are pretty flimsy on the flange. I did not like them just because it was very difficult to get a seal. The next set of three (S, M L) are white silicone eartips which also have a semi-wide bore, a pretty rigid stem, and a slightly less flimsy flange. Once again, I simply couldn’t get a good and consistent seal for my ears with these tips. The last set of tips are the style that I went with. These are a gray silicone eartip with a red stem. You get three pairs (S, M, L), once again a semi-wide bore, firm flange, firm and rigid stem and very close to KBear 07 tips yet colored differently. I found these tips work very well for me and sound great with the Airoso. I could’ve gone through every set of eartips in my arsenal, but I think I found the tips that I’ll use in the gray/red Kiwi Ears tips. Really, it’s a nice amount of eartips within the package and I’m sure that between the three styles you will find something which works for you.

Carrying Case​

The carrying case which comes packaged with the Kiwi Ears Airoso is a familiar case which I believe has been used for a few other sets in Kiwi Ears lineup. It’s a smaller black case, with a zipper, covered in what appears to be faux leather. It has the Kiwi Ears logo imprinted on the top of the case. It’s a stylish enough inclusion. Nice looking. Inside the case you have the routine mesh pocket on the topside and a soft inner covering to protect your iems from banging around and getting scratched up. I said it’s a “smaller” black case, but really, it’s what I’d call average size. Big enough to house the Airoso with the cable, extra tips too. That’s about it. Possibly a very small dongle dac like the Kiwi Ears Allegro Pro would fit nicely. So, it isn’t huge and very portable. Great for tossing into a bag or into a jacket pocket. Not bad at all.

Cable​

Okay, so here I have a slight curiosity about why Kiwi Ears chose the cable that they provide. To be perfectly honest, I think most of you will want to cable swap. I’m just looking out for you all. Not that the included cable doesn’t do its job, because it most certainly does. And, you most certainly don’t have to swap cables either. It just isn’t the most appealing cable I’ve ever seen. Now, in Kiwi Ears promotional material they state that the included cable is “upgradeable”. Well, it’s a 2-pin cable and so yes, you can replace the cable. At any rate, I’m thinking that Kiwi Ears made the decision to keep costs under $130 and they had to provide a more functional cable rather than a nicer looking cable. In truth, I find no problem with this whatsoever. Honestly, I understand it too. I have no information on the cable except that it’s a 3.5 single ended 2-pin cable and that it’s 1.2 M in length. No idea what the material is. At any rate, the cable is a very thin black cable which comes with a twist rather than a braid and terminates in a 3.5 single ended jack. Honestly, it functions perfectly and there’s no functional reason that you’d need to upgrade. Again, it does its job. Also, it’s very lightweight which doesn’t pull on your iems. So functional, but not really aesthetically pleasing.

What did I use? ​

Folks, I went through just about every cable in my arsenal, which is a decent number of cables. I had a few which seemed to pair well but the cable that I chose in the end was a budget cable, the KBear Chord 4.4. I found the sound paired the best, the look is awesome with the Airoso too. It’s really an awesome cable for this set. I believe the Chord can be bought between $25-$30. It’s a great cable and it looks dope.

Build / Design / Internals / Fit ​

Build Quality ​

The Kiwi Ears Airoso is a very nicely built iem. The shell portion is made entirely out of CNC carved lightweight aluminum with what appears to be a glossy black coating. At first, I thought the shell was made of resin but after inspection I realized that it most certainly is not resin but instead a very durable aluminum. The faceplates are actually made using titanium which is a very corrosion resistant alloy. On the faceplate you’ll notice a decent sized vent with a metal mesh grill covering it. There’s also one smaller vent towards the nozzle as well. The nozzle itself is about medium in length, meaning it isn’t so short that you’d need wider shallow fit eartips, nor are the nozzles so long that you need to find smaller tips to reach deeper. It’s a nice fitment in my opinion. The Airoso is a nicely built set folks.

Design​

This brings us to the design where I’d say that the Airoso has a pretty cool look. It’s a very simplistic and uniform design. It’s a nice looking iem. The silver titanium faceplates mesh nicely with the black shells. You’ll notice that inside of those faceplates is a raised middle section in the shape of a slot, you could say. I don’t know how else I’d explain it. Of course, you can see my pictures. Anyways, inside of this raised slot reads “Kiwi Ears” in a fancy cursive lettering. Next to the name is that metal mesh covered vent which basically makes for a semi open design. Also, Kiwi Ears used silver colored aluminum on the nozzles which strikes a nice contrast with the Shells. Again, this is a nice-looking set. It looks like it means business yet in a very simplistic manner. I like it.

Internals ​

Like I said earlier, the Kiwi Ears Airoso comes equipped with one dynamic driver and four balanced armature drivers. To be exact, that’s one dynamic driver (unknown size) with an LCP+PU composite diaphragm. The DD covers both the bass region as well as the midrange. I like the fact that Kiwi Ears has the presence of mind to use the DD to cohesively control both regions. The highs are covered by two customized balanced armature drivers and the ultra-highs are also covered by two customized balanced armature drivers. I have no idea what BA’s are used. There really isn’t a whole lot of info past what I just provided to you, but I’ll update accordingly if I find out. Kiwi Ears also uses a combination of an RC and physical crossover technology. No doubt the crossover does a nice job of providing a very cohesive sound across the mix.

Fit / Comfort ​

As far as fit goes, I have nothing but good words for the Airoso. The Airoso is a very smooth iem in build, no rough edges, and it’s fatter which enables it to sit perfectly in the ear. No doubt once I got my tip situation under control the fit became truly nice. I could honestly wear this set all day long. Each individual earphone (right/left side) weighs about 12 grams each and the weight is distributed very well. They’re simply a comfortable set. Now, I have no idea if you’ll have the same experience, but I’d be willing to bet that 80% of folks will have zero issues with comfort.

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Drivability / Pairings​

The Airoso is rated with an impedance of around 15 ohms as well as a sensitivity of about 105 db’s. This undoubtedly means that the Airoso is also fairly sensitive of an iem. I had zero issue getting the Airoso up to good volume levels on a simple smartphone, my iPad, cheap no-name Amazon dongle dacs. I’d also say that the Airoso sounds perfectly fine on less powerful sources. However, like most sets nowadays, the Airoso definitely scales with power. There’s no question about that for me. I feel like the Airoso simple tightened-up after using my dongle dacs on high gain. You really don’t need a tremendous amount of power, but it does yearn for more juice. I feel that my 1-watt daps on medium gain, using the 4.4 connector, easily did the best job, especially the Shanling M6 Ultra. However, you could really use most any dongle dac and be more than fine. So, it’s nice on lesser powerful source devices but certainly reaches its pinnacle sound with more power.

Source Pairing ​

As far as pairing the Airoso, I personally enjoy a source devices ranging from warm/neutral to neutral in tonal coloration. Which is basically every dac crafted nowadays. There’re some straight warm sources which will add a hair too much warmth for my taste, and there’s most certainly brighter sources which exaggerate the brilliance of this set. I would definitely stray from the bright and analytical style sources. I found the that Kiwi Ears Allegro Pro to fit the Airoso very well tonally. Same with the Aful SnowyNight, EPZ TP50, or the Shanling H0. Actually, who am I kidding, the Airoso sounded great off of almost all of my sources. I do like a hint of warmth which could be provided by many devices nowadays. As far as my collection is concerned, the Shanling M6 Ultra is probably my favorite pairing with this set. Still, I love the Airoso with the Fiio Jm21, the iBasso DX240, or even the Fiio Q15. Each of those are roughly inside of that warm/neutral to neutral tonal color which benefits the Airoso very well. Basically, I don’t think you have to worry too much about what you pair the Airoso with. Just try to make sure it isn’t ultra bright or too warm. I’d say the Airoso is pretty forgiving if you stay within that tonal range.

What should you use? ​

Like I said, try to get your hands on a nice dongle dac if you can. I realize that not everyone has extra money to spend on a new dongle dac. However, there are some relatively cheap options which are very capable. Really folks, I could list many devices which would fit this set well. Notwithstanding, with the Airoso, using better and more sonically gifted sources will definitelybe rewarded. Better components, better circuitry, better dac chips etc. You’d think that’s an obvious statement but not every set reacts the same. Despite that, the Airoso really does pair nicely with many devices. It’s really quite the chameleon in this way. Just try to find adequate power and you are likely good to go. I should add that if all you have is a smartphone or a less powerful dongle dac than please don’t worry, the Airoso does sound very nice even off of less powerful devices.

Sound Impressions ​

*Note: I Want to preface this sound portion of this review with a few details about my listening. First, I did burn-in the Kiwi Ears Airoso for about three full days and part of a fourth day. Roughly about 78 hours. I don’t know if that is essential or even if it helps all that much as I didn’t hear a huge difference. Then again, the Airoso didn’t sound as though it needed much out of the box. Also, I listen almost entirely with flac or better files which are stored in my devices. There’s a few mp3’s in my collection as well. The Android music player if my choice is almost always UAPP (USB Audio Player Pro), but I also use Hiby Music from time to time as well.

What’s it sound like? ​

The Kiwi Ears Airoso is a fairly large departure from the Kiwi Ears KE4. It was honestly something I didn’t expect. I like this about Kiwi Ears. They aren’t scared to change things up. Anyways, the Airoso has a warm/neutral tonal coloration, energetic, great tonal contrast with nice dynamics across the board. It’s a very fun set with moderate levels of controlled energy. Very nice timbre, nice cohesion across the mix, nothing which blatantly offends either. No saw-blade treble or undue and crazy peaks. Just a finely tuned iem that is a pleasure to listen to.

Each 3rd of the mix (condensed) ​

Now, in a very condensed manner I’ll lay out each 3rd of the mix (bass, mids, treble). If I were to call the Airoso anything I’d say it’s a slight V-shaped to U-shaped set with a definite emphasis down low. The bass hits deep, hard, and has plenty of authority. I don’t hear an intrusive bass to the point that it causes veil. Yet, enough to hit that bass drop that you like with some authority. I’d say the brunt of the low-end emphasis most notably comes from within the sub-bass area. The mids aren’t too recessed as they actually have a somewhat forward nature to them. I’d call them two parts ‘musical’ and one part ‘technically inclined’, with some nice midrange timbre to boot. You have a semi-rich note body with decent density as well. Lastly the treble is certainly emphasized nicely too. The treble is open sounding with some real nice luster, nice details, good note separation. It almost matches the bass shelf and balances wonderfully dynamically with the rest of the mix. In fact, I find the balance overall is quite nice for a more dynamic sound. I love the meaty and dense low-end coupled with the airy and vibrant treble. On top of that, I don’t find that the mids are pushed-back. The midrange still replays vocalists very well. Perhaps not to the degree of a mid-centric or mid-focused set. But very nice, nonetheless. The stage is wide, tall, and has an almost holographic depth to it with better than average layering. Which, by the way, is pretty impressive for a $129 set.

Cake and some icing​

The frequency has a certain crispness to it, a slight bite, there is some edge to the sound without coming across coarse or “the bad kind” of abrasive. It’s got a controlled edge to it which features some nice note outlines. However, there’s also some smoothness to the bulk of the sound. The analogy I’d use is that the Airoso is mostly all cake with a touch of icing. Mostly smooth, moist enough in areas too yet very clean around the edges. Granted, areas like the treble and upper mids do have a non-offensive ever-so-slight dryness to them. That said, they also have very nice note definition and above average resolution. Add to that the instrument separation is pretty nice too. It has a grain free and a fuzz free display of the spectrum along with a touch of crisp detail at the crest of most notes (depending on the track). Not quite glass-lined, but pretty well manicured for a more fun sounding set. Furthermore, it isn’t like transients are super-fast either. In my opinion transient attack through decay is actually pretty natural. The bulk of the sound is usually in the midrange and the midrange is controlled by a dynamic driver. So, it’s no wonder why the timbre is nice, transients come and go naturally, and the sound is so cohesive.

Won’t change your life but… ​

However, don’t get it twisted, the Airoso has a nicely melodic tunefulness. I really feel that Kiwi Ears did a fine job with this tuning. It’s all about dynamics, dynamic contrast, the rousing crescendos, the loud and soft fluctuations of sound, the subtle micro-dynamic volume shifts, the featherlike diminuendos. It’s all there. Now, I’m not saying the Airoso is going to add years to your life, change your life, or bring your life into focus. But… It can replay some music really damn well for $129.

Having said all of those good things, no doubt there will be detractors. It comes with the territory folks. I have friends that are so unbelievably particular that it seems nothing pleases them. You could have an awesome set like the Airoso, and to them… it’s hot garbage. That’s the world of fellow hobbyists whom I write to. The number of personal messages sent my way over what another person feels is correct over my Interpretation of sound is at least marginally laughable, but also, no one is laughing because those messages are true to them. I wouldn’t try to convince them otherwise even if I could. That’s the same as chasing after the wind. A pointless endeavor which leads to moot points. I will do my best to relay what some of those detractors may say. I suppose I went a bit long with this intro into the sound but let’s check out each 3rd of the mix in a bit more detail.

Bass Region ​

The low-end of the Airoso is one of my favorite aspects of this set. Ya know, in every review period I always check bass first. I pick a track from my “Bass Playlist” to hear what the bass is doing. After all, the bass dictates so much of what the final sound will be. Or at least it helps explain the overall sound to a degree. What I hear with the Airoso, is a bass with very solid note density. It can hit those deep bass drops in a very tightly controlled measure of palpable muscle. Not to a basshead level either. But very nice for those who desire an above-moderate bass presence. However, I wouldn’t call it a super full bass as transients are not slow, or laggy. Attack is hard edged, not fuzzy, nothing pillowy, and the decay isn’t excessively pregnant with harmonic resonances. So in that sense bass notes don’t come through overly full and bloated, rather they’re more streamlined. The Airoso low-end doesn’t come across wide in note body either. Notes are pretty tight when a track presents them that way with a more visceral and textured sound. Very nice to my ears. The lows certainly represent an area of focus on this set, but in truth the bass shares the spotlight rather well. Never overshadowing or causing veil and the bass isn’t intrusive into the midrange to the point of muddiness. You have a slight cascading drop off into the midrange which causes far more positives anything else. Really a nice sounding bass region. It’s a fun one.

Sub-Bass​

The lowest of the lows commands the spotlight on this set. No doubt the Airoso gets deep, nice extension, very well controlled, not at all sloppy, pretty manicured actually. Notes are sculpted, but voluminous, in a fairly kempt, tight, and distinct manner. Basically, there’s no haze, along with a fairly clean note contours, with a solid delineation between sub and mid-bass regions. I suppose what I’m trying to say is that the sub-bass isn’t a mess. It doesn’t smear the low-end in a deep-toned blur. There’s definition in this region and it can be very satisfying. Of course, those who don’t enjoy a semi-deep and rumbly presentation will most likely not feel the same way that I do, but man… it’s nice. I love how low and guttural the sub-levels can get. Again, not to basshead levels, but deep. Tracks like “Mancey” by Andrew Bird sound deep in a very guttural and full sense as the bass guitar strums with a low droning authority while the rest of the melody dances around with very nice separation. Or “Another Dimension” by Metro Boomin off the “Into the Spiderverse soundtrack”. The sub-levels simply vibrate in a very haptic way. You can hear that nice tactile, heavy and shuddering growl while the rest of the track plays clean and clear simultaneously. Essentially, you can feel the sub-bass with a track like this. Or any track with a more pronounced sub level. I don’t hear anything soft, nothing hollow or pillowy either. Just a nicely balanced emphasis with a good quality to it.

Mid-Bass​

Now, the mid-bass comes across slightly less commanding than the sub-levels, but that doesn’t mean that this region doesn’t add some very nice weight to the mix. The mid-bass is actually fairly quick, well defined, and punchy. Mid-bass notes keep a tight but meaty demeanor and also come across with nice texture. I find that this region has plenty of emphasis to bolster stuff like bass guitar, kick drums, etc. However, the mid-bass also isn’t boosted so much that you will hear any bloom or muddiness in the mix. In essence, the Kiwi Ears Airoso’s mid-bass keeps fairly tight reins on its note body. I don’t hear anything which I’d call one-noted, I hear nice enough separation between mid and sub-bass and the mid-bass is well able to take on slightly more complicated bass passages. Within reason. It certainly doesn’t have the speed of a BA or planar, but it does have the solid timbre of a good DD and is tuned in a way that doesn’t promote transient lag. Again, bass guitar has that fullness that a pronounced mid-bass can provide. Tracks like “Groove” by Ray Wylie Hubbard have just that. It’s meaty, dense, full-bodied, but also pretty taught. Also, the kick drums in “Move Along” by The All-American Rejects, or the kick drums in “Glass House” by Kaleo both sounds very robust and gratifyingly stout. You get the hard snap on attack at the crest of the note followed by a cavernous and hollow resonant boom. Of course, both of these tracks have some very heavy kick drums. However, even less intensely recorded tracks feature that heavy yet fairly tight delivery. I’ll say it again; the bass region is one of my favorite aspects of the Airoso.

Downsides to the Bass Region ​

The first real subjective issue (which some hobbyists will have) is centered around the amount of emphasis that Kiwi Ears afforded this region. Granted, it’s not an overly meaty emphasis, but it’s robust. Not everyone wants a heavy bass. Not everyone wants the low-end to “over saturate” the mix. Of course, the words “over saturate” are highly subjective. I certainly don’t feel that the bass region is egregiously boosted or even close to a problem, but I’m not you. So, don’t say I didn’t at least warn you light bass lovers. Also, in the same breath I would say that flat-out bassheads probably will not enjoy the low-end. Like I said, the bass strikes a nice balance with the rest of the mix, and so it certainly isn’t so boosted that it is a focal point. Not necessarily anyways. Well, in general that is. Obviously, there are tracks which are recorded heavily in this area which will definitely render the bass the focal point. At any rate, no it isn’t basshead. However, the low-end of the Airoso has a very nice balance with not just the rest of the frequency, but also it has a nice balance of quantity and quality. I enjoy it quite a lot.

Midrange​

The midrange of the Kiwi Ears Airoso is one of decent presence against an otherwise smooth and even semi rich underlying sound. You have a little bit of crispness to go with that buttery spread of smooth dynamic driver timbre. While the midrange is in no way the crown jewels of the Airoso’s repertoire, it has shown time and time again, to me, over hundreds of tracks that it has solid control, a nice technical display, and enough melodious musicality to add some rhythmic fluidity to my music. The midrange has good resolution, sounds open and spacious, and has enough clean transparency to draw out details and form mostly unsullied note outlines.

Better midrange iems? ​

That said, the Airoso also doesn’t specialize in its midrange. Not necessarily anyways. Really, to me the Airoso is more about bold energy with a balance. I would not say the Airoso specializes in its vocal delivery or timbre. There’s other ‘mid-centric’ or ‘mid-focused’ iems which are more tailored to present a better or more forward leaning midrange, maybe more organic, possibly less BA influence. While the Airoso is in no way artificial sounding, it also isn’t the most natural as you make your way up the frequency. Please don’t confuse me though as the Airoso’s midrange is definitely more natural than it isn’t and is highly enthralling. Though… you’ll hear some BA timbre squeak through from time to time, but nothing even remotely close to an annoyance for my ears. One of my all-time favorite mid-centric iems (at any price) is the Kiwi Ears Orchestra Lite. Now that set is tuned in such a way that brings the mids more forward, definitely more organic, but also not as energetic and possibly less enjoyable or engaging for some folks. It all comes down to preferences, as always. In no way am I speaking Ill of the Airoso here, but I want to help you understand what you’re getting. It’s a fun sound, an enticing sound, and positively has its own charm to it.

Good for what it is… ​

That’s where the knocks end though because I find the cohesion between frequency divisions is great with the taught and somewhat faster bass doing a nice job of matching the speed of the BA’s. Really, the Airoso is good in its transitions with an almost feathered-in gradation from the low-mids to the mid-mids, and from the mids to the upper midrange and so-on. Nothing sounds out of whack or disjointed at all. Also, note weight is a very nice ‘semi-rich’ style adding some weight from the low-end bleeding through in a very controlled manner. Now, note body isn’t super thick and lush, such as you’ll find with the Kiwi Ears KE4 for example. The Airoso is slightly leaner, less clogged between notes, more refined, more dexterous, and technically more proficient. Certainly not what I’d call thin, not overtly dry, and definitely not analytical or papery. Somewhere in the middle I’d say. I can say with confidence that the Airoso has some nice body to notes without bringing too wide of a presence to those notes and keeping a more streamlined note profile. I enjoy that the Airoso’s midrange seems to magnify the sense of clarity adding extra edge to midrange instruments along with great imaging capabilities. Vocals and instruments are quite nice too as they come across fairly naturally. Vocals are also arranged dead center in the sound field. The mids have a nice tonal contrast with expressive macro-dynamics, while at the same time keeping solid note separation and a pretty clean presentation.

Lower-Midrange​

The lower-midrange of the Kiwi Ears Airoso comes across warm/neutral to my ears with an ever-so-slight lean towards the warm. I can hear the meager weight of the bass as it just coats this region with a touch of added plumpness or additional note body. Male vocalists come across nicely too. I like the presence of male vocals. They aren’t so recessed that they come across dull or distant to my ears. Take the track “Ordinary” by Alex Warren. His voice has so much character with the Airoso. His voice is forward, pronounced, with a peppering of subtle energy to emphasize the inflections in the tone of his voice. Again, his voice is not subdued at all. Not even a little bit folks. Beyond that, his voice also comes through smooth in body with solid density. The instrumentation surrounding him is full of sparkle, the piano sounds shimmery, the bass has depth, and each instrument is very well separated. Another male singer is David Draiman of Disturbed in the monumentally awesome effort he put into the track “The Sound of Silence”. Just an amazing vocal display folks. At any rate, the Airoso has the meat, the prominence and the gravelly bass infusion to adequately capture his voice. There’re many sets which can do this track justice (full disclosure), but I cannot take anything away from how well the Airoso performs. Just wonderful.

Not as authentic? ​

On the other hand, higher pitched males tend to thin out a bit. For instance, singers like Noah Kahan in the track “Stick Season” will begin to get a hair scratchy at the crest of his notes, maybe less authoritative (of course, his voice isn’t authoritative) too. Simply not as natural as lower toned male voices. Not in any way bad, but simply not as authentic to my ears. However, folks I could come up with minor cons for every set. And please trust me, this is very much a minor offense. I actually found that male vocals sound pretty great. Way more often than not I enjoyed the sound in this region. Nice job Kiwi Ears.

Upper-Midrange ​

The upper mids are more forward (as one should expect) with a somewhat more scintillating and perky sound than the low-mids. Brighter, more enthusiastic. Though the pinna rise rarely ever becomes strident to my ears. Upper midrange notes tend to sound more distinguished or more prominent against the backdrop of most tracks. You could take darn near every female voice which has any semblance of sweet-toned vibrance, and they will come across forward and under very nice control. The upper midrange (in general) exhibits some definite upper midrange liveliness. You’ll hear some zestiness which comes across as fun and engaging, never sloppy, and never to the point of sounding outright artificial. Though, it may come across as glare to those sensitive to it. No doubt Kiwi Ears added plenty of energetic life to this otherwise smooth midrange. It has enough levity to sound airy, to sound open, to sound lively, yet not so lifted that I need to turn my volume down. If that makes sense to you. Kiwi Ears brings you right to that breaking point of where shimmer turns to sharpness… but stops just short. Again, maybe too much for some and possibly not the most natural sound, yet for some reason I really enjoy the fun spirit of this set. This vivacious sound helps in many regards. It adds snap to percussive instruments. Strings like guitar or violin have that satisfying subtle abrasiveness and great harmonics. Woodwinds generally sound anywhere from delicate, nuanced, and textured, to silvery and even resounding at times. Also, most upper-mid notes come across with a very taught leading edge along with some crunch and a nicely contoured note outline while the natural decay helps those last subtle harmonic details shine through.

Female vocalists​

The upper mids are owned by female vocalists. Yeah, there’s some males too, but for the most part this is where females reside. It is very few and far in between that the sprightliness of the upper midrange comes across as too boosted. In my opinion, females on the Airoso always sound distinct and forward. The vibrance somehow isn’t overly lustrous and to my ears it helps more than it hurts. Rhiannon Giddens sings “Who are you Dreaming of” and folks she sounds positively delectable. The tone of her voice with the Airoso is really great. There’s moistness to her voice and enough light buoyancy to every smooth intonation that her voice comes across really remarkable. No doubt she always sounds remarkable, but even more so with the Airoso’s airy but also dense note delivery. Each note that she sings is very much emotionally tilted, romantic, and somehow very inviting. Another track is “Lacy” by Olivia Rodrigo. Her voice is so soft and flowery yet in such a haunting sense. Again, the emotion isn’t lost on the Airoso. I could do this for many female lead vocals. Yes, there are the occasional tracks which can exhibit some slight BA timbre, but for the most part the sound is what I’d call an energetic form of organic.

Downsides to the Midrange ​

There’re a few downsides which may push some listeners away. First, you have to like an energetic and fun sound. If you don’t dig that, then maybe keep looking. The Airoso certainly has an enthusiastic playback of my music. Warm and dark lovers or thick and lush lovers may not entirely enjoy this set. The midrange is such an important area of the mix encapsulating the majority of the information within a track. If the mids are off, everything’s off, for most people. Except possibly for bassheads. But I digress. No doubt there will be some folks who simply won’t want something as aggressive in this region as the Airoso can be. I totally understand this thinking and this preference. Especially if you are coming from a warmer and richer sound like the Aful Explorer, Kiwi Ears KE4, etc. Another possible issue is with the timbre as it isn’t quite organic. It’s a vibrant form of organic yet just boosted in its luster a bit. I would never call the Airoso “artificial” either. It’s not that. Maybe just a hair too much glowing radiance to call it natural. Also, you’ll hear some slight BA timbre creep in from time to time. I mentioned that this is not an annoyance to me, and I mean that. I’ve heard straight BA timbre sets and the Airoso barely presents it in an obvious manner. Lastly, straight-up analytical-heads will want to keep looking. The Airoso is not a clinical or analytical sounding set. Those who love dry, ultra transparent, and perfectly precise detail monsters iems will not get what they crave for here. Yes, the Airoso is solid technically, but there’s too much fluid musicality for some of those folks, I would think.

Pretty nice midrange​

Airoso is one of those iems which is very energetic, very fun, very rambunctious and expressive in its dynamics. Those tried-and-true audiophiles who place maturity over all else may want to keep looking. However, if you can handle a bit more energy than I can tell you that the Airoso has a pretty nice midrange.

Treble Region​

Now we get to the treble region. The place where most of this resplendent energy originates from. Kiwi Ears had all the intention to create a sound which favors pleasureful amusement. As I alluded to earlier, the Airoso has a healthy lift within the treble region which adds enough levity to the mix to add an airy and uplifted presence. It’s brilliant, very open, very clean and the Airoso’s treble has some pretty good resolution too. This region is certainly one of the focal points of this set as the treble sits somewhat forward with a drier tactility to most notes. I generally hear nice separation of instrumentation and vocals with a clean imaging portrayal. The treble is textured, good body to notes (albeit somewhat dry), has a nice bite as well and I don’t find the sound too aggressive. Especially after I’ve gotten used to the Airoso. Honestly, the treble doesn’t sound forced as I don’t hear any real forced resolution to my ears. Timbre is pretty nice. Certainly, there’s some hints of BA timbre, but for the most part the treble region is definitely a bright form of natural.

Nice, for the style​

If you enjoy a sparkly treble with enough controlled shimmer and vibrancy to provide a nice contrast to the low-end weight, then you’ll probably enjoy what Kiwi Ears was able to do. Once again, I enjoy the fact that the treble is boosted to a degree, it’s a non-safe approach with plenty of air, but it never comes across too sharp, too glaring and too harsh. Like I said earlier, Kiwi Ears took the shimmer and shine right to the brink of sharpness and stopped just short. It’s a nicely tuned treble if you ask me. For the style, that is. Of course it won’t be for everyone, but of course… what is?

Transitions & Peaks​

Kiwi Ears did a great job of blending or transitioning the midrange into the lower treble in a way that sounds reasonably natural and unforced. Again, nothing disjointed to my ears. The Airoso’s treble doesn’t sound partitioned off from the rest of the mix. It’s feathered in nicely. You have a dip in the lower treble between 4k-8k, which helps to stave off some of the sibilance. Yet there’s another peak at roughly 9k within the mid-treble which does add some presence and spunk to the sound. There may be some of you sensitive to that area of the mix, but I find it to be a nice addition to the tuning.

Extension ​

Also, the treble has decent enough extension into the upper treble. Perhaps it isn’t as extended and full of vigor as some sets, but the extension is good enough to help the secondary harmonics of a cymbal strike come across with solid enough timbre. They’re energetic without the splashiness that we hear so often. For instance, in the track “In Bloom” by Nirvana, the cymbals which begin this track are well pronounced and have a nice tight decay to their notes without the prolonged splashy harmonics. You don’t have any of the annoying tinsley or chimey treble tizz to my ears. This will be important to some of you I’m sure and others… not so much. So yeah, the upper treble extension is decent as I hear plenty of info past 10k when I’m actually paying attention to it.

Speedy Treble​

This is also a faster treble which is pretty well able to take on more complicated treble tracks. Within reason as there are some tracks which are simply far too chaotic and chock full of smeared treble that no set can manage them well. However, the Airoso does a very nice job in a track like “Evil Twin” by Lindsey Stirling. Every note is precise, they sound bodied, timbre isn’t too far off, they have some crunch to notes along with solid crispness. But the Airoso can keep up with this track without blending sounds. Really some decent separation. Another track is “Magnetic Fields, Pt. 1” by Jean Michel Jarre. This is a track I only use in my treble testing playlist, and it’s riddled with treble activity coming from all sides. The Airoso handles this one beautifully, never sounding discordant or strident and the Airoso has just enough resplendent glow to provide a very fun and gleaming sound. Add to that the crisp nature of each note which comes across sharp, yet in a good way. Satisfyingly edgy, pinpoint in its note definition with pretty nice control for a non-treble-head type of set. I gotta say, if a slightly more energetic treble is your bag, then maybe check out the talented Airoso.

Downsides to the Treble Region ​

Well, for starters, anyone who detests a slightly more brilliant sounding treble… will probably not enjoy the Airoso’s emphasis in this region. I know so many folks who only enjoy warmer and more rolled-off treble displays. Lately we’ve seen more tunings which feature a less vibrant treble region, and they have gotten some pretty good praise. Sets like the Kiwi Ears KE4 for instance, the Dunu X-Gizaudio DaVinci, and on and on. However, Kiwi Ears set out to try something a bit different than simply matching other popular tunings within the market. Truth be told, I really like the decision. I like the vibrant and energetic style from time to time. It’s a nice flavor to add to a collection. What’s great is that the Airoso isn’t just a bright, dry, and thin sounding set. It also has plenty of low-end weight to easily counter the treble. The result is a pretty nice dynamic balance. The treble definitely won’t please those warm & dark lovers, but it’ll please anyone who desires to hear a brilliant treble with good technical chops, nice detail retrieval, nice separation, nice transient attack through decay, some crunch, some bite, and even decent enough extension. Having said all of that, I don’t want you thinking the treble is some extremely bright sound chock full of screaming sharpness. It’s definitely not that. Again, it’s somewhat bright with a nice balance. It’s honestly pretty well done.

Technicalities ​

Soundstage​

The soundstage of the Kiwi Ears Airoso is one of its better qualities. Granted, this set is loaded with good qualities. The stage has good width, not class leading, but very good. You have good extension up top and good extension down low which does tend to add the perception of a wider stage. The Airoso also has a fairly tall stage too. However, the depth is what begins to make this stage presentation stand out as it comes across almost 3D to my ears with its very nice psycho-acoustic rendering. This depth along with the Airoso’s overall cleanliness really does provide some very good layering of sound. Now, the stage isn’t one which sounds like a stadium in front of the listener. It is a hair more forward. While I wouldn’t call the stage “intimate”, I would say that it isn’t some cavernous and chasmic grandiose stage either. What it is to me is a well laid out stage. Again, almost holographic. All things considered, the Airoso has a very nice soundstage.

Separation / Imaging ​

The Airoso has a keen ability to separate instruments and vocalists with precision. I feel that sound separation is quite good. While the Airoso in no way has class leading technical abilities, it is good almost across the board. I said earlier it’s one part technical and two parts musical and I stand by that. However, there is an analytical or reference quality to this wholly un-reference sounding set. It’s simply clean, black background, tight note delivery, good resolution, wide stage, tall stage, deep stage, and the Airoso has a decent dynamic balance. All of these attributes add up to create a nice separation of elements within an imaginary stage. Imaging is also pretty darn nice. I don’t hear any issues with sound field placement of instrumentation and vocals are always dead center. Well, unless a recording positions them off to the side. But those tracks are weird and don’t count… Lol. Anyways, the only caveat is with bass dominant music and some highly congested tracks. Some of the heavier bass tracks will obviously mask certain sounds and skills of the Airoso. But that’s to be expected.

Detail Retrieval ​

I can honestly take everything I said about separation and imaging and walk right into detail retrieval with mostly the same verbiage. Again, clean sound, high resolution, slightly larger stage, tight note delivery, plus the sound has plenty of air to it. To my ears the Kiwi Ears Airoso has above average detail retrieval. Now, “above average” can mean a lot of things. I don’t place the Airoso with the top sets in its class for detail retrieval simply because it isn’t that analytically tuned, ultra-airy, wonderfully clinical sound which brings even the smallest bits of minutiae to the surface. The Airoso is way too melodic and dynamic for that. However, the quality of the drivers and the more pristine representation of a dynamic sound helps to do an “above average” job in this regard. I am very impressed by the Airoso and the many ways that it holds its own against the very best that $100 to $150 has to offer.

Comparisons ​

Celest Relentless ($129)​

The first set that I chose to compare with the Kiwi Ears Airoso is a very well received iem from 2024 named the Celest Relentless (Relentless Review). The Relentless is a 7-driver hybrid iem consisting of one 8mm dynamic driver and six custom balanced armature drivers. Friends, no doubt about it that the Celest Relentless is certainly one of the best hybrid iems under $150 and certainly makes sense to compare here. I gave the Relentless great marks and was very impressed by how well it handles the spectrum. A great tuning, a great unboxing, and just an overall pleasing iem. Let’s check out some of the differences.

Differences ​

To begin, the Airoso is built to a more stringent standard in my eyes as it’s made using all alloy materials while the Relentless is simply a nicely crafted 3D printed all resin set. I think it goes without saying that the all-alloy set is probably the more durable. Especially single Kiwi Ears used aluminum and titanium. Both materials are very much corrosion resistant. However, the design is a different story. The Relentless is an art piece in my mind. The design is just gorgeous. That all blue resin with the galaxy themed paint covering the faceplates is very nice to look at. Now, the Airoso is nothing to sneeze at either. It’s just simpler, more minimalist. I don’t think one is necessarily better looking than the other, but they are massively different in this regard. As far as the unboxing goes, the Relentless certainly wins out. Better experience altogether. Much better modular cable, better eartips too and it’s simply a more extravagantly designed unboxing. Celest is known for that though.

Sound Differences ​

To begin, the Relentless is even more V-shaped and slightly brighter than the Airoso is. To me the Airoso is smoother and with a closer to realistic timbre. However, these are tight margins of difference. Both sets are very fun, very dynamically expressive, and both carry more contrasted macro-dynamics. Now, the Airoso has a tighter, slightly better extended and better-defined bass region. The Relentless is no slouch at all but its bass is a slight bit more atmospheric. The Airoso has a touch more impact. The lower midrange of the Airoso is more forward to a slight degree with better body to notes. The Relentless is more forward and brighter in the upper mids while the Airoso keeps a tighter control over that region. Both sets have nice detail retrieval in this area, but the Airoso simply has a more convincing sound. It’s better for vocals, instruments sound closer to organic too. Also, the Relentless has a greater tendency to produce some shout as well. Looking at the treble differences, the Relentless is much brighter, slightly better resolution to my ears while the Airoso has better note control and also note definition. At times the Relentless can exhibit some treble sheen and can also have a touch more sibilance as well. Technically, the Airoso and the Relentless are very nice. I’d say detail retrieval is a toss-up however, the Relentless probably edges the Airoso out. Instrument separation is great on both sets, so is imaging. Though when it comes to soundstage, the Airoso simply has a more holographic sense about it. Better depth, better layering of sounds too and the stage in general sounds more immersive. Both are fine sets, but the Airoso looks to be the better buy at $129 for me.

Final thoughts on this comparison ​

Like I said, both sets are fine iems at $129. In fact, you really can’t go wrong if the sound signatures seem like they suit you. Both are easily top ten hybrids in their price range for most folks. Probably higher even. This comparison really comes down to what you enjoy. The Relentless is a hair more analytical while the Airoso has a more fluid sound. Better musicality. Still, the Relentless is a fun V-shaped set with a very vigorous sound. For me, the Airoso is the better set, but I’m not you either. You may think differently.

Simgot SuperMix 4 ($149)​

Oh, the Supermix 4 (SM4), how special you are. I reviewed the SM4 (SM4 Review) last year at some point and for quite some time I felt that it was the best hybrid under $200. Yes, it’s that good. That said, it certainly didn’t come across that good to everyone. There were definitely some mixed feelings in the community. I hold firm on that though, easily one of the best “under $200” hybrid iems. So, the SM4 is a four driver quad-brid iem which houses one 10mm dynamic driver, one balanced armature driver, one piezoelectric driver, and one planar driver. I don’t know about you but to have a set that complex under $200 is quite impressive. Truly a standout set. I have sung this sets praises ever since my review and will likely continue to do so.

Differences ​

For one, the SM4 comes in about $20 more expensive than the Airoso. Although, how Simgot kept the price so low is beyond me. Anyways, the Airoso is certainly built better than the SM4. You have the aluminum / titanium of the Airoso against the resin of the SM4. Both are built nice enough, but the Airoso is obviously more durable. As far as design, both iems are understated and very simple. I do favor the Airoso here, but many folks love the simplicity of the SM4’s design. Again, the Airoso has a total of five drivers to the SM4’s four driver quad-brid setup. I would say for sure that the unboxing experience of the SM4 is a bit better. You get a better cable, better case and the eartips are a squash.

Sound Differences ​

To start, the Airoso is slightly warmer, slightly more organic in its timbre, and has the more authentic take on my music library. Both are nice, but the Airoso has the edge there. The SM4 is a bit brighter, more crisp, more edgy while the Airoso has that nice smoothness to it. The low-end of the Airoso hits deeper, denser, more haptic in its rumble, and more impact. Both sets have reasonably tight bass replays though. The Airoso simply has more of an emphasis. The midrange of the Airoso sounds a hair more forward, slightly less sprightly too. Once again, the Airoso has a touch better and more realistic midrange timbre while the SM4 has slightly better detail retrieval. The treble of the SM4 has a tad more brilliance, but also better crunch, note body, better bite, and in almost all ways the SM4’s treble wins out here. The way Simgot tuned this treble is flat-out awesome at the price. Now detail retrieval is almost a wash but the SM4 does have slightly better illuminated details. Separation is about the same, Imaging too. However, the Airoso has that nice stage. Better width, better depth and better layering of sounds. Both the SM4 and the Airoso have their own charm about them. Truly two of the best iems featuring multiple drivers under $150.

Final thoughts on this comparison ​

I love them both. I couldn’t choose which I like better if I tried. Both sets create a solid standard for any other brand to try to replicate. To be honest, whatever set I had in my ears during testing was the set I liked better. Just two awesome iems. Having said that, this is about you and finding the set which fits your specific preferences. Also remember, the SM4 costs $20 more, which just may be the deciding factor for you.

Is it worth the asking price? ​

The Kiwi Ears Airoso has an MSRP of $129 and in my mind, it is a fantastic price for this set. I’m not going to beat around the bush on this one. There’s no point, you all should at least have a slightly good idea about how I feel after reading this review. Friends, the Airoso is undoubtedly a stellar iem. Five years ago, this set would’ve cost much-much more. The hobby has simply blown up. Better gear began hitting the market to the point that there is now heavy competition in every price point. Of course, for you there should be some underlying caveats with this set. Like, can you afford the Airoso? If not, there are some very solid hybrids for cheaper prices. $129 is a fortune for so many people across this earth. Not everyone has the disposable income to drop on a $129 set of iems. Next, does the sound signature even fit your tuning preferences? It may not. Just because something sounds great to me, doesn’t mean it’ll sound great to you. This is true across the hobby. Every review I complete I will afterwards see other perspectives from other people who are polar opposite of me and what I hear in a set. The same goes for the consumer. However, to answer this question I have to answer for myself. The answer (which I’ve already stated) is most definitely the Airoso is worth every last penny. It’s a great buy folks.

The Why… ​

Because the build is substantial and very solid, very durable. Kiwi Ears went the extra mile and used both aluminum (shell), and titanium (faceplates) in their build. Friends not only is this set built wonderfully, but it’s also relatively light and totally ergonomic. Another partial reason why it’s worth the price is because of its understated and minimalist sleek design. Some may argue that this is a not a good reason why any set is worth its price, but I feel that design has at least some sway with prospective buyers. Anyways, Kiwi Ears wasn’t trying to blow your mind with the look here. They went the route of class with the Airoso. They gave it a classy, austere, courtly, and stylish design. However, it’s always about the sound when answering this question. Friends, the Airoso is simply a fun set with mature intentions. Very well controlled, very clean, technically savvy too. The bass is deep and it’s robust, bullish even, but also lithesome and dense. It’s spry, it’s very well defined and it has some nice impact as well. The midrange is a wonderful mixture of musical and technical with nice timbre, an energetic sound, big macro-dynamics, and the Airoso is very dynamic and expressive, which ultimately makes it very engaging to my ears. The treble is crisp, has some crunch, decent extension, and has a nicely resolving sound. All technical attributes like detail retrieval, instrument separation, sound field imaging, layering and transient responses all point to a technically adept iem. However, there’s also a strong musical fluidity and rhythmic quality to the tuning as well. Again, a fun sounding set with mature intentions.

Ratings (0-10)​

Note: all ratings are based upon my subjective judgment. These ratings are garnered against either similarly priced sets or with similar driver implementations or styles with the unique parameters of my choosing. In the case of the Kiwi Ears Airoso ratings below, that would be $100-$150 earphones of any driver configuration. Please remember that “ratings” don’t tell the whole story. This leaves out nuance and a number of other qualities which make an iem what it is. A “5-6” is roughly average and please take into consideration the “lot” of iems these ratings are gathered against. $100-$150 earphones of any driver configuration are a fairly large sized scope of iems. So, it should be something special to see a rating above a “9.0”. My ratings are never the same and each set of ratings tells a different story. Each time you read one of my ratings will be unique to that review. Basically, I create a Rating that makes sense to me.

Aesthetic ​

–Build Quality: 9.2 Wonderfully built.

–Look: 9.0 Class look and design.

–Fit/Comfort: 9.2 Fit and comfort is very good for me.

–Accessories: 7.5 Decent unboxing.

–Overall: 8.7

Sound Rating ​

–Timbre: 8.9 Bright/natural

–Bass: 9.5 Speedy, authoritative, textured, impactful.

–Midrange: 9.0 Nice musical/technical sound.

–Treble: 9.4 Brilliant, resolute, nice bite & crunch.

–Technicalities: 9.2 Performs admirably.

–Musicality: 9.0 Nice musicality per the tuning.

–Overall: 9.2

Ratings Summary:​

This is one set of ratings which I feel requires almost no explaining. I rated the Kiwi Ears Airoso against any set of any driver configuration between the price of $100 and $150 US that I have in my possession or know and understand like the back of my hand. I will not rate a set against anything I haven’t heard (who does that?) and I do hope that you take these ratings with a grain of salt. Friends, I complain about them (ratings). I reluctantly and grudgingly complete these ratings as well. Full disclosure. I don’t think they help you very much and I’m truly hoping that none of you base buying decisions off of them. Each rating will likely need updating in about 3 to 6 months as well. I never update them, ever. These ratings are time sensitive folks. In this hobby new iems come in like the rain in a rain forest. Finally, ratings don’t provide any nuance whatsoever folks. I’ve almost never finished a Rating and thought “That explains everything”. Actually, ratings explain nothing and skew the consumer’s view. Okay, I got that off my chest, moving on.

How I do it…​

Again, I rated the Kiwi Ears Airoso against any driver configuration iem between $100 and $150. The nice thing is that I have almost all of the good sets in this range at my disposal. There’s a few that I don’t, however, so please keep that in mind. As much as I don’t feel that ratings help, I actually really enjoy this process. It gives me an excuse to re-hear some iems which have been collecting dust, and it is the best way of rating that I’ve seen. Literally have the sets you are comparing and rating against in ear. I use different tracks particular to each rating and go through every single set that I have in that range. No, I do not listen to the full song, just enough to get a good idea and good judgements.

Explain Yourself!! ​

So, I really don’t feel that I have much explaining which needs done with this set. Really. I suppose that some bassheads would not give the Airoso a super lofty “9.5”. I’m not a true basshead. So, there’s that. Another rating area which may get some scrutiny would be the “9.0” midrange score. I could see folks saying that the Airoso deserves a higher score, and I could see some folks saying that my rating is too high. Those who desire a warm, rich, and even more musical approach likely wouldn’t give the Airoso a score that high. I gave it a “9.0” simply because it is very good across the board in the midrange. However, there are simply better midrange sets. Sets like the Dunu Kima 2, the Fiio FD15, the Hiby Yacht 10, and a few others that I rated higher. I actually feel I went low on “Musicality” and I realize that now, after the fact. Too bad, can’t change it. Lastly, I’m sure that some folks will think I’m nuts for the “Timbre” rating. Guys and gals, what can I say? I’m just me. I hear what I hear, and I speak what I hear to you. Simple as that. Ratings are locked in.

Conclusion​

To conclude my full review and feature of the Kiwi Ears Airoso, I have to first thank the wonderful folks over at Kiwi Ears, including @EvelynZ for providing the Airoso. I am very thankful and also very impressed Kiwi Ears. Thank you for being a stand-up brand. Also, thanks go out to you, the reader, who decided to use your free time to check out my thoughts. This means the world to us at Mobileaudiophile.com. Truly it does. Every click matters folks. So, thank you very much.

Other Perspectives ​

Now that you’ve read my words about the Kiwi Ears Airoso, I really want you to go read other people’s opinions. Like I say in every review; we are all different. Each and every one of us has the capability of being completely different. Different likes and dislikes, different music libraries, different source devices, different hearing abilities, and we haven’t all been down the same road in audio which greatly affects how we view some products. So please take the time to check out other thoughts as it is of the utmost importance that you get your purchase right. Beyond that, I think I’m finished friends. I hope you are all doing well, stay as safe as possible and always… God Bless!!

- Introduction -
Friends hi everyone, today in the review we will look at hybrid headphones from Kiwi Ears for $129.
They come in a small box with a nice design, there's an image of the headphones themselves, there's a company logo, and the name of this new Airoso model.

- Technical specifications -
Drivers: 1 dynamic driver + 4 balanced armature
Sensivity: 105dB
Impedance: 15Ω
Frequency Range: 20Hz-20kHz
Plug type: 3.5mm

- Let's take a look at what's included -
1.High quality audio cable with connectors 2 pin and 3.5 mm jack.

2.User manual.

3.Three sets of silicone eartips.

4.Branded case.

5.IEM
The headphones are very small front panel is made of aluminum alloy, and the inner part is made of black resin, they look to me quite interesting and to some extent unusual, on the front panel here is a small ventilation hole and the inscription kiwi ears on both headphones.

And here is a standard 2 pin connector for connecting the cable, and on the inside there is a single hole for compensation, which performs its function well, so when you use the headphones is absolutely no vacuum effect, which can not but please.

And the soundhole here is completely standard, it is metal, has a diameter of 5.8mm, a clear edge for better fixation of the ear tips and is protected by a metal mesh.




Well and fit and comfort as you understand friends here everything is excellent, headphones compared to other various hybrid giants are quite small, sit in the ears very tightly and there are no questions to the fit, and soundproofing is at a very high level, in general, in this regard here is a complete order, you can use them as a complete ear cushions good choice is quite large, and with any other that you like more.





- Tuning and Conception -
Well now let's talk about how the KiwiEars Airoso hybrid headphones sound, and this is how their frequency response graph looks like, and these headphones have a 10dB bass boost, with an extremely smooth transition to the lower midrange, and the emphasis in the upper midrange here has a clear correspondence to my targeting, which personally makes me very happy, so these headphones in this area do not sound to me overly sharp or aggressive, and the balance is just perfectly preserved, and high frequencies surprised me here, as they are very long and do not have any sharp peaks or dips and only very smoothly fade after 17kHz, which is a very good result and as you understand there are no questions to tuning here, everything is done very competently without any experiments and you can say here is a perfect balance, and now let's analyze the sound of these headphones in more detail.

- Low Frequencies -
In KiwiEars Airoso bass frequencies have a noticeable power all the same 10 dB is already very good and noticeable amplification, but I note that their power here is not at the expense of accuracy, as the bass here is punchy, super collected and most importantly perfectly controlled. It does not press on you with any excessive massive pressure, but on the contrary, demonstrates extremely clear and textured transparent presentation, so literally every bass hit is felt with a quick and energetic impulse, while the bass structure remains extremely airy and not overloaded with additional density.
And the sub-bass in these headphones is pronounced perfectly and it is not just present, but tangibly sets the necessary depth and foundation, but does it without any unnecessary muttering or smearing.
As in his delivery he is very collected, dense and never gets out of control, keeping perfect intelligibility even in complex multi-layered arrangements. And I would like to note that the bass attack is really sharp, with clear boundaries and perfectly laid energy, so fans of electronics and in general any modern music will definitely be satisfied here.
As well as the mid-bass here is very clear, perfectly worked out, without the slightest hint of looseness. Heavy bass parts are transmitted with lively, and natural dynamics, not overly imposing in its presentation, but at the same time retaining a tangible physical component, which as far as I am concerned is very necessary in any headphones, especially without the use of a bone driver.
Yes, and percussion instruments sound very dense and maximally delineated without any blurred hum or excessive softness, bass control in these headphones is really impressive, as even on saturated electronic tracks, the bass remains structured and collected, absolutely.
And of course, when comparing with obviously bass-headed models like KiwiEars x HBB Punch, these headphones do not go to bass-headed extremes, because there is no such excessive pressure or such a powerful flow of low frequencies, but at the same time the bass in these headphones really feels quite powerful, rich and very airy in its presentation.
So in genres like rock, jazz, or instrumental music, it gives literally great intelligibility, where every bass guitar and double bass sounds very naturally textured, without any overblown overload. And in electronic music we get a very energetic drive, with a good balance between density and speed, so the sound remains very lively and as full as possible.

- Mid Frequencies -
Well, in the midrange Airoso demonstrate literally amazing transparency and airiness, but at the same time I note that the presentation of this range remains very neutral, restrained and accurate. As there is no unpleasant aggression or brightness in the upper midrange, the midrange in these headphones sounds very natural, smooth and balanced, i.e. exactly as I like, and I think not only me, as I hope that there are many fans of this kind of presentation.
And the vocals in these headphones are very clean, rich and intelligible, but without any unnecessary intrusiveness or excessive emphasis on itself.
As it is strongly climbs forward in the construction of the sound stage as in headphones already with Harman tuning, but on the contrary very carefully and literally blends into the overall sound picture, maintaining a noticeable sense of lightness and spaciousness.
Female and male voices sound very natural, with good layering and density, but without any additional amplification of emotionality or artificial emphasizing of micro-details. And this makes vocal parts very clear and detailed, but at the same time not shouty and not overloaded with unnecessary nuances that distract you from listening to the music, because sometimes it is not always appropriate, I think, if for example you just want to immerse yourself in the music and feel the whole composition without paying attention to all sorts of small nuances.
And the instruments in these headphones as for me are transmitted with excellent timbral accuracy, but without excessive warmth or coloration in their presentation. Guitars, strings, brass all sound very refined, with good separation, and without excessive expression, which is very important if you do not like too energetic sound. That's why the same electric guitars in rock sound crisp with a good crunch, but not aggressive, and acoustic instruments in jazz and classics convey a natural sense of volume and space of the whole sound picture.
And I think it's very good that the midrange in Airsoso maintains an excellent balance between analytical and musicality; it doesn't sound dry or lifeless, but it doesn't try to artificially add any extra emotion. As a result, the sound remains extremely accurate, transparent and natural, without the harsh peaks or simplistic smoothness of simpler headphones, so to me it's a great option for those who appreciate a clean, detailed midrange without being overloaded or overly emphasized.
- High Frequencies -
Well, the high frequencies in Airoso are highly technical and analytical, and simply gorgeous transparency and airiness, with literally perfect balance. And I am pleased that there is definitely no deliberate smoothing or muting, but on the contrary, there is even a small added accentuation that emphasizes detail and makes the sound more clear, intelligible and very informative.
Attack of cymbals, shakers, percussion all sound very precise, with fast and natural dynamics.
There is absolutely no dirt, veil, darkness or artificial softening in this range, because when listening to it, it is immediately noticeable that each sound is very clearly delineated and presented with excellent layering and even with some pleasant sharpness. At the same time, the treble does not roll off into some dry sterility, but retains a sense of lightness and transparency, without the intrusive stiffness or metallic flavor that is characteristic of some very cheap armature radiators, and here with this order, so there are no complaints about the quality of the armature drivers themselves.
And in classical and jazz, this range opens up particularly well strings, brass, cymbals sound with amazing intelligibility, but without excessive aggression. And in electronic music and metal, the upper range adds clarity and speed of attack very well, making the sound collected and detailed.
And it's important that these headphones give us a technical and analytical presentation of high frequencies, but without any unpleasant harshness or tiresome sharpness. They do not mask the nuances of the recording, but on the contrary, even emphasize the textures and the smallest shades of sound, while maintaining the comfort and naturalness of presentation. And as far as I'm concerned, these are the treble frequencies that really bring out the details and make the sound crystal clear, but without unnecessary distortion or armature coloration.
- Sound Stage -
Well, the soundstage in these headphones feels moderately wide, with a great emphasis on depth and precise positioning of instruments. It's not quite as spacious and expansive as the open models, but it definitely doesn't feel cramped, as the space feels very natural and well-organized.
The width of the stage in these headphones is sufficient to avoid the effect of so to say tunnel sound, the instruments are definitely not in a pile, but with a good and noticeable spread in the panorama to the left or right. In live recordings you can clearly hear the position of both musicians, as well as the difference between channels and natural background reverberations.
However, it is the depth of the scene that is particularly well developed here. KiwiEars Airoso create a noticeable sense of layering near and far are clearly separated, forming a three-dimensional sound picture. For example, drums and bass guitar in rock compositions are located a little deeper, behind the vocals, and reverberations of instruments help to convey the space of the whole hall.
And separately it is worth noting the separation of instruments as there is no smearing or superimposition of sounds on each other as in inexpensive models. On the contrary, here literally every instrument retains its clearly verified position, and the vocal already confidently occupies the entire center of the stage.
This is especially noticeable in complex arrangements, where it is important to clearly hear each sound element. For example, in metal, guitars, drums and vocals do not merge into one pile, and in orchestral recordings there is a good clarity of arrangement of groups of instruments.
And to sum up KiwiEars Airoso demonstrate a stage with good width, but to me with even more impressive depth and localization. They create a natural, comfortable space that is perfect for complex layered compositions, live recordings, rock and electronic music where a sense of depth and sound movement is important.
My conclusion on this headphones!
And the conclusion on hybrid headphones Kiwi Ears Airoso I got the following: it is really very good and competently tuned headphones with excellent textured bass, neutral middle and a little more emphasized area of high frequencies, but guys here we have a truly very transparent technical and detailed sound that will be appreciated by many audiophiles, and the most important thing that is very happy here is an extremely balanced and versatile presentation that perfectly reveals absolutely different musical genres, in general, from myself these headphones I safely recommend for purchase!
Buy this headphones on Linsoul Official Website:https://www.linsoul.com/products/kiwi-ears-airoso

KIWI EARS AIROSO

The cheaper, the better tuned KE4!

Pro:
- A well-balance tuning.
- Tight and cohesive bass response.
- Clear and natural vocal rendition
- Good treble extension.
- Solid technical performance.
- Can runs most genres rather well.
- Good driver coherency.
- Great Value
- Small shell with decent build.

Cons:
- Average detail and resolution.
- Missing abit of reverb and overtones.
- Dynamic-range is not the widest.
- No 4.4 BAL plug option in 2025?

[MY PERSONAL HEAD-FI GRADING]
1 ★ - Appalling! please avoid this!
2 ★★ Subpar offering, there are better options out there!
3 ★★★ Decent with some caveats! Not a bad pick!
4 ★★★★ Not perfect but solid choice ! This should be in your shortlist. A nice addition to your collection.
5 ★★★★★ One the best in class! You should go right ahead & buy one! A must have!


Kiwi Ears Airoso 4½★★★★
Driver Configuration : 1DD + 4BA Hybrid
MSRP : $129.99



▓▒░ SOUND-SIGNATURE ░▒▓
It has a neutral, bright-leaning sound with a sub-bass boost. The mid-range and vocals are more forward in the tri-frequency range, while both the bass and treble have ample extension at both ends of the spectrum, resulting in a well-balanced sound.

▓▒░ BASS/LOW-ENDSOUND ░▒▓
- The low-end is emphasized in a way that makes it sound fast, tight, and precise. While this level of bass may not satisfy hardcore bass enthusiasts, it is more than sufficient for delivering a well-balanced bassline.

- The sub-bass has a slightly more prominent presence with respectable low-end extension and texture. However, its short sustain and tight attack mean that rumbling, growling, or booming sensations are more controlled and focused. Those seeking a high-resonating sub-bass might disappoint.

- The mid/upper bass is almost identical in character, though slightly less present. The attack still maintains a decent density and impact. Its steady presence adds warmth and body to vocals and instruments, with kick drums and toms offering a more noticeable thud. While the drum strikes may not have the hardest slam and the bass guitar could use with more grunt, ghetto bass lacks the usual bounce. Additionally, bass drops and distortion elements aren’t as well-defined.

- While the bass may not be the last word in definition, considering its tuning and price point, the bass performance is no slouch. More importantly, it remains enjoyable to listen to.

▓▒░ MID-RANGE /VOCAL ░▒▓
- The cohesive bassline, combined with its well-articulated treble response allows for a balanced, smooth, clear, yet natural mid-range and vocal rendition.

- As a result, it make its one of the better mid/vocal centric set among its peers. Vocals and instruments (guitar, piano, violin, strings, flute) will sound more to the fore and often given a greater focus in the mix.

- Tonally, they have a good sense of note-weight behind them with subtle texturing and adequate range of dynamics. Both male and female performs just as rewarding on stage. And they're well separated from the background elements across various tracks.

- Moreover, there are no issues with graininess, sharpness, shoutiness, or sibilance is heard. It sounded clean and clear.

- While it may not capture every nuance or expression of vocals as effectively as higher-end models, it still conveys emotion and offers a good level of micro-detail.

- In fact, it strikes a nice balance between clarity and euphony, delivering a solid mid-range performance nonetheless.

▓▒░ TREBLE/HIGHS ░▒▓
- The treble performance is the highlight of this set. It leans slightly toward the brighter side of the spectrum, but it is nicely executed. The sound is airy and open, without being overly bright. It rises and dips precisely where it needed, avoiding any unwanted resonance that could spoils its response. Unlike some other bright-leaning sets, it doesn't mask the lower harmonics.

- As with many budget sets, the balance-armature’s treble response can sometimes show graininess, haziness, sharpness, or harshness when pushed to the limit. Even the KE4, its predecessor, struggles with this, particularly at higher volumes or on poorly recorded tracks. Fortunately, this isn’t an issue with the Airoso. Its treble is more refined and forgiving, delivering a smoother, cleaner, clearer sound.

- Constant hi-hats, cymbals, and drum brushes sound rather pleasant. Despite their prominent presence, the trailing shimmer or sizzle of notes doesn’t come across being too metallic or sharp. The snare drums have a nice crispy high-pitched rattling sound. As for synthetic noises like electronic zings, rings, buzzes, and electric guitar, they stand out with just the right amount of bite.

- While the treble detailing isn’t the absolute best, it’s more than adequate for critical listening.
It’s worth noting that with brighter pairings, the treble brilliance may cause some fatigue, so treble-sensitive listeners should be aware. However, for most people, this won’t be a deal breaker.

- The treble response is surprisingly well-tuned. For just $129 bucks, that’s an impressive feat.

✧ ════ •TECHNICAL PERFORMANCE/ASPECT• ════ ✧

- The STAGE width feels wide. However, the perceived front-to-back layering is not much, and the vertical headroom feels somewhat limited. The mid-range/vocals seem to occupy the majority central space of the stage, surrounded by bass and treble instruments.

- IMAGING PROWESS is generally accurate, though the image definition isn’t the most vivid I’ve heard. That said, the localization and positioning of sounds between channels are solidly presented.

- The background is darker than average, enhancing the SEPARATION LEVEL. While the space between instruments isn’t overly generous, it maintains good consistency in keeping the sound boundaries distinct, preventing from further congestion or compression issue. Though, on a more demanding tracks like progressive rock or symphonic metal it will starts to struggle a little thanks to its somewhat 2D-stage dimension. Still, given the tier it competes, I have no complaints.

- DETAIL RETRIEVAL isn’t its strongest suit. While macro-detail is solid, it falls short ever so slightly when capturing finer micro-nuances present in both vocals and instruments. This level of detail handling is typical for this price-range.

- As for DYNAMICS, the range isn’t extremely expansive but is wide enough to handle most genres well. The contrast between loud and soft elements in vocal and instrument playback tends to be more subdued.

- The overall TONE AND TIMBRE sound mostly natural to my ears, with no moments where it feels off. It managed to sound fast and smooth yet natural at the same time which is quite pleasant. The attack isn’t the sharpest, but it’s not overly blunt. The decay is relatively fast but remains precise. The notes maintain good weight, although a greater sense of reverb or overtones would enhance the sound, as it feels lacking in certain instances.


✧ ════ •POTENTIAL SYNERGY TWEAKS• ════ ✧
- EARTIPS: The stock ear-tips works just fine but if I had better listen experience when using the SPINFIT CP100 (Non-Plus). These enhance vocal clarity while adding more low-end body and reducing some of the top-end sizzle.

- DAC/AMP: Given its bright-leaning treble, it's best to avoid pairing it with a brighter source, as this can throw off the treble balance and potentially lead to fatigue over time. For example, it pairs better with the warmer, less aggressive Tanchjim LUNA than with something like the Tanchjim SPACE, which has a more energetic treble.

✧ ════ •BUILD/ PACKAGING/COMFORT• ════ ✧

~~~Kiwi Ears Official Photos~~~
- As with most Kiwi Ears products, the build is solid but not particularly remarkable. The shell feels sturdy, though not overly premium to the touch. More importantly, the shell isn’t too large and lacks any sharp edges that might cause discomfort.

- The unboxing experience is fairly standard for Kiwi Ears—nothing too exciting—but it does include a small, practical carrying case and six sets of silicone eartips, ranging from small to wide bore with three different sizes each. My only complaint is that, at $129, they could have included a more substantial cable with a 4.4mm balanced termination plug.


QUICK HEAD-2-HEAD
vs Kiwi Ears Aether/Stock 3.5SE Cable/Spinfit CP100 (M)
- The AIROSO has a neutral balance tuning with a bright tilt, while the AETHER features a warmer, V-shaped sound.

- The bass on the AIROSO is quicker, deeper, punchier, and more visceral overall. And not to mention, AIROSO’s bass control is a step above. In contrast, the AETHER has a warmer, boomier, and loosened response. Its sounds is fatter, bigger, with a slightly slower attack and decay. When it comes to bass detailing, AETHER takes the lead.

- The AIROSO is more mid-centric of the two, with vocals taking up a larger space on the stage. The separation between vocals and background elements is clearer, up to a certain threshold. Meanwhile, the AETHER has a softer focus on vocal reproduction.

- The vocals and instruments on the AETHER sound more natural and lifelike, with greater liveliness and expressiveness. It does a better job of highlighting subtle nuances and textures, including reverb and overtones. However, the AIROSO’S vocals are cleaner and clearer, without the occasional graininess that can sometimes appear on the AETHER.

- The AIROSO has superior treble extension, giving it a more airy and open sound. Overall, it sounds clearer, and cleaner compared to the AETHER.

- The AIROSO has a wider, more open soundstage and darker background while the AETHER offers a slight edge in perceived depth.

- The AIROSO has sharper imaging and spatial cues, while the AETHER presents a larger image.

- On simpler tracks, the AIROSO can separate its elements more clearly than the Aether. However, on more complex tracks, like rock, metal, or orchestral music, the AETHER'S planar speed allows it to maintain more consistent separation while present additional layers in the music.

- The AETHER is more resolving, with micro-details presented in more layers.

- Not only is the AETHER more dynamic, but its tone and timbre also sound more natural. From end to end the notes feels more complete and better defined. Despite its softer attack, the sustain and decay are more accurate. To the contrary, on the AIROSO, some notes may fade a bit too quickly.

- The AIROSO’S has a smaller shell. And cheaper to own as well.

- Both are easy to drive. Just that the AETHER requires a smidge more power.

- Both of have nigh identical packing and accessories.

“ To my ears the Airoso has better tuning. It sounds more balance and has greater extension on both ends. But it is the Aether that will capture the hearts of many audiophiles. Its more dynamic, its more technical and the overall timbre just sounds slightly more natural.”

◤FINAL THOUGHTS◢
This is what the KE-4 should have been. To my ears the Airoso is much better tuned yet sounds more refine at a fraction of the price. It has become one of my favourite Kiwi Ears after the Quintet. It has every bits of everything to keep you listening to it. For just $129, I’d recommend this set in a heartbeat, especially if you're cross-shopping for a well-balance set at this price-point.

========================================================================

【SOURCE & GEARS】
● Native FLAC Files [44.1Khz 16bits-96Khz 24bits]
● Foobar2000 [ROG Strix G814JVR (2024)] [USB C Thunderbolt]
● Samsung S24 Ultra [as my DAP phone][ App- Foobar2000]
● Tanchjim SPACE / LUNA Asano Tanch / xDuoo Link2BAL / Kiwi Ears Allegro Pro
● INNTAK HIFI OTG Type C to Type C
● Eartips : Spinfit CP100 (M)
● Stock Cable 3.5MM Single Ended.
========================================================================

【PLAYLIST／TEST-TRACKS】​

1977 Fleetwood Mac - Dreams ★
1982 Chicago – Hard to say I'm sorry. ★
2003 NARUTO Original Soundtrack I – Wakiagaru Toushi ★
2008 K.will (케이윌) – 소원 (Great King Sejong OST Part.1)
2009 Maksim – Exodus
2010 Ichiban Ushiro no Daimaou (OST) – Kokoro no Oku De Ha
2012 Imagine Dragons – Night Visions - Demons ★
2014 Grabbitz – Here with you now. ★
2014 BoA – MASAYUME CHASING
2014 Hyolyn – 안녕 Good bye ★
2015 KOKIA – I Found You ★
2015 K MISSING KINGS (OST) - New Kings
2016 K RETURN OF KINGS (OST) - Return of Kings
2016 K RETURN OF KINGS (OST) - If you die.
2017 Berry Goodman – Zutto (ずっと) ★
2017 SawanoHiroyuki[nZk]:mizuki – ViEW
2017 Namie Amuro – Hope
2019 K SEVEN STORIES (OST) - In Pursuit Of
2019 K SEVEN STORIES (OST) - Lost Small World
2019 Blade & Soul (OST) – Half-Moon Lake
2019 CAROLE & TUESDAY VOCAL COLLECTION Vol.1 – Light a Fire ★
2020 Paradox Live Opening Show (1st E.P) – BAE – BaNG!!! ★
2020 Paradox Live Opening Show (1st E.P) – cozmez – Where They At ★
2020 倖田來未 (Kumi Koda) – GET NAKED (Kiyoshi Sugo Remix)
2020 倖田來未 (Kumi Koda) – again (MATZ Remix)
2020 premiere fleurs – プリンシパル
2020 Love Live! Nijigasaki – 朝香果林 (Karin Asaka) – VIVID WORLD ★
2020 Fujii Kaze – へでもねーよ”／Hedemo Ne-YoSeishun Sick
2020 King Gnu – 三文小説 ／Sanmon Shosetsu ★
2021 OWV – Fifth Season ★
2021 加藤 ミリヤ (Miliyah) feat. Yoshida Brothers – この夢が醒めるまで ★
2021 Aoi Teshima – ただいま★
2021 Official髭男dism – Cry Baby
2021 Chanmin BIJIN 美人 – Morning Mood
2021 門脇更紗 (Sarasa Kadowaki) – きれいだ
2021 Mirei Touyama – 美忘録
2021 SELECTION PROJECT Vol.1 – Only one yell -天沢灯ソロver.- ★
2022 Belle (Original Motion Picture Soundtrack) – Million Miles Away (ENG vers.)
2022 rei (E-girls) – Dark Hero.
2022 rei (E-girls) – IDNY
2022 I can fly (Special Edition) – Bleecker Chrome - You will shine ★
2022 I can fly (Special Edition) – YOSHIKI EZAKI x Bleecker Chrome - UP ★
2022 BEAST TAMER (OST) – じんわり感じている幸せ
2022 Ado – 会いたくて
2022 Ado – 踊
2023 La prière – Sweet Dreams ★
2023 Bungou Stray Dogs 4th Season ED – Luck Life – しるし★
2023 UMAMUSUME PRETTY DERBY - Hat on your Head!
2023 Anna – 花のように (Hana no You ni)
2023 riria. – 貴方の側に (Anata no Soba ni)
2024 Dungeon Meshi OP – BUMP OF CHICKEN – Sleep Walking Orchestra
2024 Ernie Zakri, Ade Govinda - Masing Masing ★
2024 Paradox Live THE ANIMATION OST – 25 幻影武雷管 - Trauma ★
2024 Bartender Kami no Glass OP – Takaya Kawasaki – Stardust Memory ★
2024 Maou no Ore ga Dorei Elf ED – Sayaka Yamamoto – Blue Star
2024 Spice and Wolf Merchant Meets the Wise Wolf OP – Hana Hope – Tabi no Yukue/ Destination of the journey
2024 Tonari no Youkai-san ED – Aoi Kubo – Iro no Naka (風媒花)
2024 Sayounara Ryuusei, Konnichiwa Jinsei OP – LUN8 – Together Forever
2024 Sayounara Ryuusei, Konnichiwa Jinsei ED – EverdreaM – 君と見た景色
2024 Natsume Yuujinchou Shichi ED – Toshiki Kondo – こまりわらい (Komariwarai)
2024 Hololive FLOW GLOW – FG ROADSTER ★
2025 Ameku Takao no Suiri Karte ED – The Gospellers – will be fine feat. Anly ★
2025 A-Rank Party wo Ridatsu shita Ore wa OP – L.E.I. – Enter ★
2025 Arifureta Shokugyou de Sekai Saikyou S3 ED2 – iScream – Metamorphosis
2025 Watashi no Shiawase na Kekkon S2 OP – Riria. – Shiawase na Yakusoku. ★
2025 ONE OK ROCK – DETOX (Japan & International ver) – This Can’t Be Us ★
2025 Татьяна Куртукова - _ MATUSHKA ULTRAFUNK (REMIX BY. Satirin) (SLOWED) ★

★ Main-Test-Tracks/ A glimpse of what listen to 90% of the of time.


Do take my words for what it’s worth. Afterall, I am just one man. ╮(╯▽╰)╭

THANK YOU SO MUCH FOR READING! HAVE A GOOD DAY WHEREVER YOU ARE! TAKE CARE!

Disclaimer:
- This unit is sent to by Kiwi Ears (@EvelynZ ) . Thank you so much for making this review possible.

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EXTRA PHOTOS

Review Of The Kiwi Ears Airoso​

Introduction​

Another year brings a plethora of novel and captivating products from Kiwi Ears. It appears that Kiwi Ears are expanding their expertise beyond In-Ear Monitors (IEMs) and Digital-to-Analog Converters (DACs)/Amplifiers. Despite their well-established reputation and substantial following, this renowned company has ventured into the Bluetooth and Headphones domains. Their entry into the true wireless open-ear TWS market with Kiwi Ears Attiva and their first headphone, the Kiwi Ears Division, which I recently reviewed and thoroughly enjoyed, marked a significant milestone. Since then, they have introduced a range of headphones, including the Ellipse and Atheia models, as well as Bluetooth headphones such as the Ardor and Aventus. In between these releases, they unveiled a new IEM called the Airoso, which serves as their budget-friendly mid-range option. Fortunately, I had the opportunity to try it out. However, before delving deeper into the review, I’d like to clarify a few points.

Disclaimer​

*Since this unit tour was organised by the kindly people at Linsoul, I am grateful to them. As I've said in all of my evaluations, the same is true for this one: all of the concepts I've expressed below are entirely my own, original ideas that haven't been influenced by anyone else. If interested, go to this link.
*I am not associated with the connection, and I receive no financial assistance from anyone.
*For the remainder of the review, I will refer to these IEMs as “Airoso.”
*I am using different ear-tips for convenience and better versatility.
*Finally, I will only evaluate the Airoso based on its performance, even though I will explain how it feels and seems physically and aesthetically.
*Please understand that all opinions expressed in this review are my personal perspective and are not intended to offend anyone’s beliefs or experiences. Therefore, I kindly request a respectful and thoughtful approach to this review, even if it differs from your viewpoint.

Specification​

Airoso offers a generic configuration that was once a standard in the IEM market around this price range. However, this configuration became outdated when micro planar, planar, and bone conduction drivers emerged. The Airoso is a multi-driver hybrid setup with a 1 LCP+PU composite diaphragm dynamic driver for the bass, two balanced armature drivers for the highs, and two more balanced armature drivers for ultra-highs. While the balanced armatures are not specified, the dynamic drivers are also not detailed.

The shells are made of skin-friendly high-quality resin which is black in colour, shaped to provide an ergonomic fit. I personally found a good seal and fit with the stock tips, and the earphones are quite light, causing no fatigue or pain even after extended listening sessions. And because the shells are incredibly lightweight, I didn’t experience any discomfort or fatigue after listening to my playlist for hours on end with these.

The faceplate is made of CNC machined titanium and aluminum alloy, giving it a silverish-gray shade. It features kiwi ears in a black space vertically in the center of the faceplate, raised with a small vent below the engraved Kiwi Ears. The nozzle is also made of metal and is averagely sized with a decent length. I believe the stock tips will fit most people comfortably.

The included cable is a generic black cable with a 3.5mm termination plug and two pin connectors that Kiwi Ears offers with most of their IEMs. While the cable is adequate for the price, it could be improved. However, Kiwi Ears does provide eartips in three different types and sizes.

In addition to the cable and eartips, a vegan leather case is included in the packaging.

Technically, the Airoso has an impedance of 15 Ohms and a sensitivity of 105dB. The frequency response range is from 20Hz to 20kHz.

Sound​

Airoso delivers a neutral sound signature with a surprising emphasis on the sub bass. This unexpected focus makes it more engaging and enjoyable than most IEMs tuned for such a response. The tuning reminds me of the Simgot EM6L, a detailed and perfectly tuned IEM that lacked vibrancy and wow factor for some audiophiles. However, the Airoso excels in delivering that punch and engagement that one would expect.

Honestly, the response on the graph appears generic. The treble is elevated more than it should be tonally, but the control over exposing the nuances is exceptional. I find it well-tuned. The same can be said about the bass.

In the midrange, the vocals have a forwardness and expressive aura that I’ll elaborate on later. It’s a detailed and packed IEM that offers clarity and excitement. Let’s explore the sound further to uncover more details.

Treble​

When it comes to the treble, the mix is well-expressed and forward-sounding, whether it’s the instruments or the vocals. Most notes are present and clear, with a sharp and tactile quality that doesn’t go overboard. The upper treble region has good emphasis, creating an airy and spacious feel. The vocals sound complete and full, but with a slight lean quality. The response is tonally favorable, and the notes are detailed and clear, adding a shimmer and sparkle to the mix that’s noticeable.

The lower treble region has the same energy and forwardness, bringing everything to life. The vocals and instruments have a more prominent response, making everything sound vibrant. While this forwardness isn’t tacky or overpowering, it effectively projects the presentation, whether it’s the vocals or the instruments.

Tracks like “Mizukagami no Sekai” by Marina Horiuchi sound majestic without any tinny or sibilant sounds. Her vocals and instruments sound tonally right and airy, drawing the listener’s attention to each note over the spectrum.

“Everywhere” by Fleetwood Mac also sounds sparkly and shimmery at the beginning of the track, without any offensive characteristics. The vocals and instruments are equally prominent, and with the airy space across the presentation, the vocals sound magical.

Overall, the treble region presents a vibrant, detailed, and well-expressed presentation.

Mid Range​

So, when it comes to the mid-range, it’s addictive and forward-sounding, with a focus on the vocals. The timbre is slightly metallic but delivers good tonality and sounds airy and fresh. It’s one of the best mid-range qualities I’ve heard at this price point.

The upper mid-range has great energy that resonates with the lower treble, creating a forward-sounding mix with more heft and weight in the notes. Especially with female vocals, the instruments have a bit of bite and zing but are in the background yet prominent enough to engage the listener.

Another great aspect is the refreshing and spaciousness it offers. The vocals are clear and prominent, while the instruments complement them without any peakiness or shoutiness.

The lower mid-range sounds a bit subtle and less prominent in the mix, despite delivering a good amount of heft and weight. The vocals and instruments sound clean and revealing, which is surprising for a rich and dynamic-sounding set.

The vocals and instruments in this region provide good clarity, making the overall response sound vivid and on point. For example, listening to “Kokoranashi” by Majiko sounds very revealing and prominent in the mix, especially the female vocals, which usually sound dull but wholesome. The vocals bring more clarity and revelation, making it a more interesting track to listen to. The guitars and drums sound snappy and well-resolved.

Similarly, listening to “Somebody That I Used To Know” by Gotye sounds playful and engaging, bringing out the vocals to sound enigmatic and clear.

Overall, the mid-range region is revealing, clear, and forward-sounding.

Bass​

The bass, unlike its representation on the graph, sounds well-controlled with clear details and texture. Like the treble, it’s tuned very well, with impactful and distinctive aspects that provide a clean and detailed presentation with a punchy and dynamic quality. The emphasis is on the sub-bass region, which brings out a subtle rumble in the mix that rattles a bit in the ear canals. However, the punches have a good amount of impact, helping to produce a powerful response with good note weight in the mix.

On the other hand, the mid-bass lacks the slam and thumps that could have added more fun. However, from an overall perspective, the clarity and clean presentation I understand. It doesn’t mean that the mid-bass doesn’t have enough meat; the bass notes are easily noticeable and prominent in the mix, but that heft isn’t very well expressed.

Listening to tracks like “Frontiers” by Awitch sounds powerful, especially when the kick drops. The notes have good heft and presence, bringing clarity and resolution. However, the delivery isn’t very forwarded and more weighty, unless a part emphasized with bass comes in.

On the other hand, listening to “Are You the Only One Now?” by Zeal & Ardor sounds surprisingly expressive. The bass notes have proper prominence, effortlessly heard in the mix. They’re distinctive and clean-sounding, adding more characteristics to the overall presentation of the track.
Overall, the bass region is well-controlled, punchy, and detailed.

Technical Performance​

Coming to the technical aspects, I believe the Airoso excels in its overall presentation compared to its competitors. The most noticeable aspects that emerge immediately after using these are the attention to detail, clarity, and separation. Let’s delve deeper into these aspects.

Soundstage, Sound Imaging & Separation​

When it comes to the stage, the presentation is holographic, offering exceptional depth, width, and a sense of airiness and spaciousness. The imaging is sharp and precise, providing remarkable clarity and a deeper comprehension of each note. Additionally, the separation of the notes is evident, making it effortless to pinpoint the source of each sound.

Speed & Resolution​

The resolution is excellent, as both the macro and micro details are effectively conveyed in the mix, which is quite uncommon in an IEM within this price range. The rapid attack and decay of the notes contribute to maintaining a clean and clear sound. The resolution is truly remarkable.

Sound Impressions ​

Sources​

Sony WM1A - While listening to the Airoso with the WM1A, the response sounds more balanced. The vocals are slightly tamed and richer in sound. There’s a hint of warmth and elevated lower mid-range and mid-bass that adds the missing heft, making it sound closer to a whole-sounding. The treble sounds smoother than detailed but brings all elements to the same level, contributing to the balanced sound. This rich and balanced sound makes it more favorable and easily a safe pairing.



FiiO M15S - While listening to the Airoso with M15S, the response emphasizes every region of the music, bringing everything forward in a well-controlled manner. The treble sounds sparkling and vibrant, while the vocals and instruments are both well-expressed in the mix, creating a very engaging and interesting presentation. The bass is more prominent in the mix but is controlled with punchier and better-textured notes. With a detailed exposure, it does draw the listener’s attention.

Tracks​

Millet - Anytime Anywhere
Anri - I can’t stop the loneliness
Kohana Lam - A Few Sentimental
Kohana Lam - Loving Me, Loving You
Uru - Kimino Shiawasewo
Uru - Kamihitoe
Kujira Yumemi - Kenka
Majiko - Kokoronashi
Anly - Sukinishinayo
Kohama Lam - A Few Sentimental
Kohana Lam - Loving Me, Loving You
Miliyah - Kono Yumega Samerumade
Rokudenashi - The Flame Of Love
Yu-Peng Chen - A New Day with Hope
Yu-Peng Chen - Another Hopeful Tomorrow
Yu-Peng Chen - For Riddles, for Wonders
Valentino Khan - Satellite
Kai Wachi - Happier By Now
Jawns - Erotica
ISOxo - how2fly
Kai Wachi - Happier By Now
Weeknd - Popular
YUNGBLUD - When We Die(Can We Still Get High)
Bring to Horizon - Kool-Aid
Middle Kids - Bend
FLETCHER - Leads Me On
Loathe - Aggressive Evolution
The Weeknd - Save Your Tears
Sigrid - Burning Bridges
AURORA - Black Water Lilies
AURORA - Runaway
X Ambassadors - Renegades
Lupe Fiasco - Words I Never Said
Macklemore & Ryan Lewis - Can’t Hold Us
Gotye - Somebody That I Used To Know
Jay-Z - Run This Town
Lady Gaga - Poker Face
Lady Gaga - Just Dance
Ladytron - Ghost
Travis - Love Will Come Through
LINKIN PARK - Somewhere I Belong
DJ Shadow - Six Days (Remix)
Hoobastank - The Reason
Ricky Martin - I Don’t Care
Tool - 7empest
Tool - Vicarious
A Flock Of Seagulls - Space Age Love Song
Zack Hemsey - Vengeance
Elton John - I’m Still Standing
The Moody Blues - Nights In White Satin
Micheal Sembello - Maniac
Guns N’ Roses - Sweet Child O’ Mine
A.R. Rahman - Kun Faya Kun

Conclusion​

Airoso delivers a remarkably detailed and revealing response, and in my opinion, it stands out as one of the best options in the $100-$150 price range. Its tuning leans towards vibrancy and engagement, even though it maintains a neutral sound with a sub bass boost. This is truly an exceptional achievement by Kiwi Ears. I have no doubt that if given the opportunity, it will deliver exceptional sound performance, especially if you’re seeking a neutral and well-expressed sound across the treble, mid-range, and bass frequencies. However, I would suggest that treble sensitive people might want to try it out before committing to a purchase. Overall, I wholeheartedly recommend the Kiwi Ears Airoso.

Kiwi ears Airoso Hybrid Universal IEM
Redcarmoose Labs March 3rd, 2025

As far as consumer groups, the Head-fi crowd has always been a small unique grouping, though getting bigger by the day! This enthusiast group is made up of hobbyists who fall into subcategories, of music lovers and gear heads……..and a mixture of both. Though keep in mind Kiwi ears sell to the whole IEM market. Meaning there is a pretty good chance the majority of the Airoso Universal IEM buyers will never even visit Head-Fi. Also my dear reader, remember most of us reading are not the norm. We have spent way too much time and money to just call this activity a hobby, it is an obsession and a way of life. While examining a new IEM is fun, it is also important here at Redcarmoose Labs to show where it performs in relation to similar price point IEMs which came before it……….and even more pricey examples of the IEM art. Not only that, but describe in detail how the overall IEM personality is, and how it could be a side grade from what you have, or an addition to your collection which could set it apart from the rest, thus valuable!


Kiwi ears:
While I have reviewed about 98% of everything they have made, the company as a whole is still uniquely surprising. Surprising as they not only offer IEMs and a few CIEMs, but also make portable DAC/Amps and full-size headphones now! In fact in the last month they have come out with a plethora of new gear!

The Aventus Full-size at $89.99
The Ardor Full-size at $99.99
The Atheia Full-size at $349.00
The Ellipse Full-size at $79.00
The Division Full-size at $49.00
Then, they came out with the 2 IEMs named Airoso and the Kiwi ears Aether.

It is safe to say Kiwi ears are on a roll. This progression of creativity and stature comes about from a company growing and showing strength. The strength is in the manufacturing chain, the procurement of parts, but also is the Research and Development sector. Yep, successful companies have the Research and Development budgets to hire more talented tuners, and provide the research equipment to realize such creative products. Not only that Kiwi ears never ever repeat themselves.

We all know of companies which continue to seemingly make side-grade product releases into infinity almost. Hello same/same manufactures, you know who you are, but can't ever change!

Where is the excitement to buy another variation of what we just purchased?

Kiwi ears are not like that, even their full-site headphones that they have released in the last 30 days each have an intended user group and adjacent price-point. Each full-size headphone sounds different. Why am I going off on such big tangents here? I’m simply showing that while much of Kiwi ears products share a small aspect of their sound that reminds you that you are listening to a Kiwi ears product, also often the tuning is new and exciting. The last IEM I just reviewed is the Kiwi ears Aether 15.3mm Planar IEM, and it has a reference tuning to where every single tone, every note and sonic event is canvased outward into the stage, it is not neutral-flat (what-ever-than-means), but showcases a warm, extra subtle bass boost and giant stage offering.

The Kiwi ears Airoso DD X 4BA Hybrid Universal IEM is very much a different animal:
Here we are remembering how the Hybrid idea is super important. Important because DDs add a quality of physicality and realness to bass that BAs just can’t do. Though going back to the start of this review, remember most buyers of this product will take a stretch of confidence to obtain the Airoso, not being into IEMs as much as us guys. And…….what are those buyers hoping to achieve here? Simple, treble detail and bass. They don’t even know what these concepts are, or how the balance of IEMs work. The buyer of the Airoso is simply going to a shop, or reading reviews online and looking to fill a need and a want, a desire to find an IEM which sticks-out among the thousands of IEMs sold today. That need and want is not only a substantial low-end but a detailed and well presented upper midrange and treble experience. Remember just a few years ago, you had to pay an enormous price to get treble air. This extra boost in upper detail is what used to separate the lower priced IEMs from the upper tier and TOTL IEMs.

You see, the Airoso is one of my favorite Kiwi ears IEMs. Sure I like the new Aether 15.3mm Planar a little better, wait, a lot better.

But still the Airoso came on one day, then the Aether came the next. Such is life, that the order of how you hear IEMs means a lot. And sure the Aether IEM was already reviewed by me. But something took place in that review……..a side-by-side. Yep, I tested the $129.99 Airoso against the $169.99 Aether IEM. And……you know what happened? History happened!

Later I will place them into a battle once more, in this review, but I came to the realization that the Airoso has differences to the Aether that substantiate its existence. That there was a deep homecoming vibe to hearing the Airoso that reminded me that before the Aether, Hybrids were my favorite way to go. Now keep in mind that Planar IEMs have a taste of Planar timbre, but that has almost all but gone away from the modern Planar tone. And BAs still have a taste of BA timbre, I mean this is how the actual sound is created and it is difficult to mask or subdue such flavors of the day. Though one thing Kiwi ears has done is incorporated this new crossover network and chosen special BAs to use which in-turn minimize any off-timbre.

So here we have two concepts in upper midrange and treble going on. That number one Kiwi ears is in no way trying to hide the treble and upper midrange, they are not trying to dampen it or subdue it, and secondly such upper midrange and treble are instead being used to add extra ideas as to which the Airoso is about, seemingly being that budget IEM which does anew what the past IEMs were not. Now sure I may sound like I am promoting the Airoso like no tomorrow, and I will come clean…….my first impressions were really, really good. The resulting first impressions were due to how natural the how technically correct the upper midrange and treble were found to be, that and the extra extensive bass ideas were balancing them out……creating the ultimate V response. Well not the ultimate, but really, really good for the price-point here.

Side-by-sides:
Here side-by-sides can do two things. One, they show overall quality of replay in comparison to one another, and two they actually have their side-by-side ability to outline a specific character feature. Plus it reinforces reality as past memories are only so good. I can’t tell you how many times placing a new IEM up against a past favorite has changed the way I thought about both IEMs. You see these reviews are subjective when you really get down to it, even though a form of objectivity is strived for, this is human perception, which is persuaded by many psychological phenomena. Also the side-by-sides allow not only for specific value to be determined (at the point of testing) but can showcase various ideas as to playback in relation to the other IEM, which will give the reader clues about what he or she likes, or dislikes. Meaning each listener holds values to a point, that at times they are purchasing an aspect of the response and how it relates to their whole collection of IEMs, and music acquisitions. Here I spent a week deciding on which IEMs to compare. At times this idea of which IEMs to choose becomes instinctual and fast, though this time I chose IEMs (intellectually) due to past fame, and (in this case) chose an IEM (the Aether) due to recent fame.


Side-by-sides: left to right………..

1) The Kiwi ears Quintet: $219.00-10mm DLC, 2BA, 1Panar, 1PZT Hybrid IEM
2) The Kiwi ears Aether: $169.99-15.3 Planar IEM
3) The TANGZU ZETIAN WU: $149.00-14.5mm Planar IEM
4) The Kiwi ears Airoso: $129.99-1LCP-PU DD, 4BA Hybrid IEM

So when I was starting this review section I realized also that one of the main reasons I chose this grouping of three to compare is because I love them. Sure the Wu has been bettered, in fact it has been fully run-over and killed by the Aether. Still memories about it hold true, even if it ended-up being almost brought-out to become the side-by-side punching bag. One of the very best delusions in reviews is how this IEM may still be good because it does this or that, and still has a charm. Yet, it is 2025 and IEM technology has seen under new $200.00 IEMs beat-out the 2013 $1500.00 TOTL Flagships. People who invested in these IEMs of yesteryear don’t want to truly see the writing on the wall, they are better-off saying that they still like a few aspects of this past TOTL expensive IEM. When in reality, reality is just that………the current ability to produce a real and correct idea of musical playback, with closer to correct timbre, evenness and completeness at hand. The first Hybrid IEM was the Ultimate Ears Triple Fi 10 which came out in 2006, yet times were sparse and in slow motion back then with purchases of and talk about the Triple Fi 10 going onward from 2010 on..................

Low priced IEMs from 2025 are simply better because technology has moved forward from the dark ages of the 2013 IEM market. Sure there is nothing wrong with liking older IEMs, they are like that old collection of shoes you have or clothes, to where they hold memories and experiences, heck they proved their 2013 worth, only the future is now here, we are living in it!

I’m using the SIMGOT AUDIO LC7 modular cable in 4.4mm, the SIMGOT AUDIO new Black Donut ear-tips and the Sony WM1A with MrWalkman’s firmware on all the tests today with every IEM, and the following music tests.


1) The Quintet:
I have been the biggest promoter of the Quintet IEM, I started the Quintet thread here at Head-Fi and have always thought of it as one of the very best values of 2023! And……..do you want to know one of the aspects of the Quintet value, why people are still talking about the Quintet to this very day? Treble and upper midrange details, offering a glimpse of more expensive IEMs.

You just can’t throw this grouping of all kinds of different drivers together and not get a result, well at least Kiwi ears will get results here!

The Quintet:
While both the Airoso and the Quintet weigh 5 grams each, the Quintet is larger and longer, gaining size to hold all those extra parts inside. Though keep in mind the Quintet custom universal shell design means they are creating a more curvy IEM shell, and subsequently allowing those parts inside to fit slightly deeper into the outside ear. Plus an extra nozzle length is adding nozzle extension factors. So here the Quintet has a tad bigger stage, and there is less Quintet treble and upper midrange emphasis, to where the Quintet has a slight planar and PZT character.

I’m still going to go with some ideas as to my first Airoso impressions, where I compared the Airoso (in real life) to my memory of the Quintet, and found the upper midrange and treble to hold a slight extra Airoso “pureness”.

As such now with the full-on side by sides I also notice a forwardness that the Airoso owns, due to this event of 4BAs being tuned just that much more intensely. So both natural and intense is the Airoso treble and upper midrange trademark!

Where Airoso pretty much competes with the Quintet as far as bass style and authority, it is just that upper midrange and treble energy of the Airoso way pushes the extra energy bewildering (overshadowing) what bass is there. So if the Quintet was too treble or upper midrange energy for you, you better stop reading this review at this very moment. But, one last idea, that if you are thinking you can romance this extra V shaped bass like the Quintet bass before, sorry the party is of a different theme. Where the Quintet simply offered more bass noticeability and due to that bass noticeability, held as such an extra redeeming feature!

So along with the Quintet extra smoothness from a more downplayed treble and upper midrange experience, the extra Quintet stage gets you visualization of the bass, with less distraction from the upper frequencies, that and there is an added polish that having all those drivers gets you, call it sophistication........maybe? It is more money in the end! But the Airoso is more direct in the upper midrange experience along with the boosted treble, that makes for the (overall) personality profile at hand. The Quintet still holds it's own even today, being very different (tonally) from any IEM I have heard.


2) The Kiwi ears Aether:
Look, I will not beat around the bush here. The Aether is the best sound for the money to come out of the IEM market in years, and years. And just like how the Airoso was easier to drive than that Quintet, the Airoso is also easier to drive than this big old 15.3mm Aether Planar. Yet, like said earlier the Aether is more reference, with added warmth, there are no snow balls chucked at your face here. Flatter, yet still holding a small amount of Planar tone, just like the Airoso has its own BA tone, you can't take that out, the best thing to do is grasp it and come to terms with it if possible.

There is also a way that the Aether projects this thicker note weight of treble items into the mix, where the Airoso does the same only they hold less weight and are faster into and out of the instant.

The proverbial elephant in the room is that while the Airoso stage is no slouch, the Aether stage is just that much bigger, though the Airoso upper midrange and treble make their own world up there for you to visit.

This visit may be a little shorter in stay due to prolonged intense-intensity adding to a short and sweet stay, and not something you may drift off to sleep with? Bass with the Airoso holds a very robust and correct style of tone, especially if it is not song-file frequency-wise overshadowed, causing the Planar to almost showcase that 15.3mm slight lumbering, but this is not really an issue. It is just the separate driver of the Airoso allows for a free flowing, not connected bass, to exist and flourish operating inside its own home yard into the stage………regardless of my very own trash talk prior.


3) The Wu:
Ahhhhh. My old stomping grounds. That there was a time back in the last 1/4 of 2022 when the Wu could do no wrong. And believe it or not the Wu is still for sale (at retailers) as I just checked. Holding a 14.5mm Planar cohesive idea of playback, in comparison to the Airoso Hybrid. Not promoting as big of stage as the Aether, yet even holding thinner ideas of upper midrange and treble not going to the Aether idea of profound note-weight in replay. Yet of course thicker note-weight than our Airoso. Here the stage at this moment is Wu fantastic. That sure there is this extra mid bass that the Wu is known for, and there is a size to it, that may be bigger yet slower than the Airoso. Big giant smoother idea of treble and upper midrange examples……making the Airoso seem like it is again thinner air blasting and holding worth, yet showing itself to also make this treble detail seem like even more realistic yet forward detail..............Hello, hello!


Construction:
It could be said the Airoso is perfect in a way. Why? Due to the medium small size and only 5 grams weight, we are really taking it easy on the ears. In fact this is an IEM I can wear for unlimited amounts of time due to both comfort and……….well the more comfort at hand. As such the aluminum nozzles hold ear-tips on like no tomorrow, and the actual length and angle of the Airoso nozzles mean many ear-tip (freedom) choices can be found. This is the style of ease-of-use from a well form-factored IEM!

The titanium faceplate seems stylish, as well as the top-vent blowing air into our stage as well as blowing outwards (adding to the great pace at hand)………..it is the air vent that is a trademark feature here! 2Pins are flush and never give trouble. There is also a vent off the back.




Cable:
It is what it is, and while fine, I used other cables to access 4.4mm amplification from my DAPs.

Package:

Music tests:
The Airoso has experienced 5 days of burn-in.

The music tests were an event here in that since I’ve been so hard on the Airoso during the side-by-sides I was looking for music that may make the Airoso that much more of a digestible IEM item? But also I will look for music which challenges the Airoso and makes light (sorry) of the brightness (sorry) at hand. Meaning before reading this section, and before me writing this section it may be thought of the Airoso as being selective as to what it wants to play well, and we will find out, as there could in-fact be trebly electric guitars that are too much, or vocals that are too forward? Let’s find out.

First off……….
Look, I've used this album for years to demonstrate IEMs ability. Heck the album Anastasis makes every IEM sound like a million. It glosses over timbre issues, adds stage, even downplays any rough ideas as to cohesiveness and adds the feeling of pace, if you can believe it or not. But also in my studies I found the forth (number 4) song Amnesia to sound especially wonderful with the Airoso. Let’s go!



Timestamps only pertain to digital file, not video.
Dead Can Dance
Anastasis
Amnesia
44.1kHz - 24bit
The world string instrument decays right at 00:00 make their way-out faster than needed......as here regular BA decays seem longer. Also just not that this style of instrument is right in our upper energy wheelhouse. I mean the Airoso was kinda made for doing these string instruments.

At 00:07 the piano and bass along with the drums start off. I can’t help but embrace the overall stage presented here. I can’t help but admire the string instruments and realize that not only is it slightly over-the-top bright, it is still (in-a-way smooth) and acceptable.

Probably this is the overall character still being shown for what it is? Though there is more, gloriously more……..it is the substantialness of the bass, and bass drum……holding those needed contrasts. Right when we were smitten with the deep depths, an extra midrange filagree of effects takes notice right at 00:11……..and I am not sure what instrument this is, other than a sound effect made with a sampler wrangled into a non-identifiable.

But the effect is perfect, adding stage here and making you go wow. IEMs are at times all about the "wow-factor". This upper midrange region is where this all takes place, and the tone is protected into the outskirts of the stage.

At 00:40 the piano comes in and nails the timbre here. Somehow again this song is an example of how a really good song file can add to the listening experience. And that experience is somehow each and every element is separated and shown, delineated and clear.

As this is one demo track that didn’t ask to be included in the review, it demanded to be in the Airoso review.

Along with that 00:40 comes a wash of synths, which find their way into their very own home in the stage. That this bass is by nature a little lumbering, yet with-in that the Airoso nails the bass levels too. At 01:13 the vocals show, and that’s the thing………Brendan Perry’s vocals sound 100% correct. Now this correctness does not come from too forward of vocals like you could easily guess up to this point in the review.

Yes, they are vocal-forward, but in no way like a vocal specialist IEM might do. It is that you’re in your favorite restaurant and the steak is brought to the table, and it is the perfect temperature………a memorable experience, and even more of a stand out feature because this is an under $200.00 IEM. I mean to level with you, it sounds like more than $200.00 style vocals…….maybe the projection, maybe the over-all tune, I’m not sure where it is from? We can hear the vibrato in his voice, we can hear the subtle extras of the reverberations applied to his voice. BAs...........

Sure, these are IEMs that showcase vocals and make them magic! Sure there is a tid-bit of BA timbre held inside the effects washes, but at this point, I could care less, probably because everything as far as imaging is just so big and giant found into the stage.



Timestamps only pertain to digital file, not video.
Ghost
Hunter’s Moon
From Halloween Kills OST
44.1khz - 24bit
So this was a song I have used repeatedly to understand what town we live in......in Airosovile. The fact that we are witnessing a well recorded and well played technical Hardrock/Metal song.

Here at the start we are rewarded with big electric guitar strings…………..And while the musical event is not as technically close to perfect as the Aether, there are bag-fulls of win here still.

I mean BAs do stings naturally good and wholesome while still also maybe showcasing a tiny bit of off-timbre. Still the attacks of the strings………really any strings are the Airoso’s forte here. Right at (the end of) 00:03 the drums and singing starts. That while there is really no other word than crisp to describe this event. Though it is correct, still there may be limits to the volume used due to this crispness at hand. The features that are of value are the exact same as the prior song……the good separation of events, the stage being thick offering room out front and behind, mostly side to side but some up and down too. Again it is the dramatic size displacement that is the money here. And you could only guess the clarity of vocals, to where they are not out front like vocal centric IEMs but positioned fine.

At 00:31 there is a series of cymbal accents, you know the ones that go at the end right before the song's chorus. These cymbal accents are out on their own, showcasing a level of clarity/sculpturing and detail uncommon for the under $200.00 price-point, and that was what Kiwi ears was attempting to accomplish here.



Timestamps only pertain to digital file, not video.
Gdanian
Induction
Shield Emitter (feat. Tineidae)
44.1kHz - 24bit
Here we are attempting to unearth the cosmic abilities found in this single IEM of man's creation. Each IEM is an artistic statement regardless of cost,,,,,,,,seemingly able to generate an entire alternate world for use to visit. Of course big and enveloping music like what Gdanian does helps us. But more than that we want to learn if the extremes, in bass and treble finite details are replayed here. This single song has inherent capabilities of sound effects……..small metallic sounds, found into their own soundstage. And you know what, from prior experience with other music we will find gold here………….let’s see.

Shield Emitter (feat. Tineidae)
Around the 01:28 mark I hear them, the twinkles, but these effects are slightly more subdued than I guessed. Now nothing wrong with that, remember we are listening to a $129.99 IEM. That at 01:32 the song gets going into introducing the main synth elements; a style of Blade Runner synth......................that while before we have found this stage and complete experience bigger and bolder with other IEMs, even more immersive. Still this is no slouch, but not as dramatic as I was expecting? I mean truly as a scan back and forth among the song looking for any new ideas to write about, I am given a big replay, except when it comes down to it, other less midrange and treble forward ideas of replay were better, maybe because of the V bass balance, in that this is a Bass Ambient style of music, and somehow the bass here is a slight bit timid?



Kaveh Cohen, Michael Nielsen
Forza Motorsport OST
Brotherhood
44.1kHz - 24bit
Timestamps only pertain to digital file, not video
So I needed an equalizer here. I don’t mean EQ, what I mean is an example of a song that I know forward and back, a song that I have used countless times with countless IEMs, that I totally understand. This song is kind-of the test song of test songs. To where there are both instrument ideas of tone that can be closer to correct or farther away from correct, there can be a naturalness and a completeness of stage, a formation of stage where I know where it can travel to stage-wise. To where if there is a balance here, a Kiwi ears balance at hand and I can find it, and not only find it but relish in it?

Brotherhood:
For starters this is an instrumental and an electronic game OST. So right off we are looking for ideas that are not going to jump into focus, except musical ideas which promote gameplay.

Tones which support the visuals and not distract from them. Really this almost isn’t a song but almost a song sketch………and that it is OK, that the number only goes so far. Heck what do I know, I have never played this video game, but I know from studying movie OSTs that at times it is not the amount of music that is important, it is how effective what music is there and how it is used.

Brotherhood:
At 00:09 the rhythm starts. The bass starts, even the main piano keys are also introduced. After playing this song and going to different parts over and over my main value that I get out of it is Kiwi ears balance. Now this may on paper not sound like much, but in reality it’s almost everything with an IEM. It means that if this balance is obtained, it even makes-up for drama into how certain tones are heard. Meaning sure there are certain IEMs that play one or two genres of music well, and even better than well…..fantastic. But get them the wrong genre and they will show faults. With the Airoso there is a section where the beat even starting at the 00:09 mark, and while that consistent metronome beat is heard, it is not heard as a slap, but as an actual drum beat…….the way it is supposed to sound. Then the piano, it is also realistically and timber-wise correct, even though it is slightly higher in tone, separating it tonally in the mix. This effect also launches the piano into the stage, into a bigger and wider positioning than some IEMs. Though this is what Kiwi Ears is going for. At 00:27 we hear this wonderful substantial bass shelf promoting the extended reality of bass keys for creation, actually this whole song is synthetic……..probably never recorded other than (line-in) off the mixing board, and that is OK with some music.

At 00:42 we are greeted with money! This is how and why I recommend the Airoso so much. And……..it is not a big deal, this little additive to the song, only it is done 100% right. Again if balance is obtained and even, completeness and correctness are achieved, we can let the upper midrange and treble have their moment in the sun!

All that happens at 00:42 is there is the introduction of another lower synth, that adds to both the fullness of the song, and the soundstage. Now I don’t want to make this more than it is…….but just the way the Airoso attempts to do this is great, and even more great when you realize the $129.99 price point.


Conclusion:
There are a lot of choices in the IEM world as of 2025. This ability for manufacturers of the world to make thousands of IEMs is a first in human history. I mean this Airoso is nothing new in part choices, though what sets it apart is a fluid natural mixture that in the end comes-off very well rounded, able to be driven just by a phone, but scales upward with your best of gear. When I first heard the Airoso I thought it was one of the very best Kiwi ears IEMs made to date, better than the Orchestra Lite, better than the Quintet. Why? There is this mixture of added treble and added upper midrange that adds drama and seemingly resolution at hand. The bass kicks hard making a very contrasty and V shaped idea of fun. Sure there is upper brightness and stage, though it sounds 95% natural, and that pureness was the very first thing I noticed, that the sound was in no way brittle or scathing.

Look, the Airoso isn’t everything, but it does showcase an older driver configuration brought to a value price point, even winning-out over many more expensive Hybrid examples. This driver and crossover technology is evolving still and instead of trying to reinvent the wheel, Kiwi ears simply brought the budget Hybrid one step close to perfection. The changes here is that for this kind of money you get treble details, and you get a professionally tuned IEM that goes along for the ride with any and all musical genres, except maybe the Ambient Bass genre?

Inside of those musical genres you will find the fitment of the Airoso to be world class, as well as the imaging placement and balance to be correct and of value. What else do you want for $129.99? It comes with a new edition of the Kiwi ears case, 9 sets of ear-tips and a usable cable.

Kiwi Ears Airoso
Precision Crossover 1DD + 4BA Hybrid Drivers IEMs

• Precision Crossover Technology
• Custom Dynamic Driver Design
• Four Balanced Armature Drivers
• Durable Premium Build
• Upgradable Detachable Cable
• Comfortable Lightweight Fit

$129.99 USD
https://www.linsoul.com/products/kiwi-ears-airoso
https://kiwiears.com/products/kiwi-ears-airoso

Technical Details​

Impedance 15Ω ±1Ω
Sensitivity 105dB SPL/mW ±1dB
Frequency Response 20Hz - 20kHz
Cable Length 1.25m (detachable)
Connector Type 3.5mm
Cable Interface 0.78mm 2-pin
Inside the Box

• 1x Kiwi Ears Arioso
• 1x Detachable Cable
• 8x Pairs of Eartips
• 1x Carrying Case
• 1x User Manual

Linsoul website: https://www.linsoul.com
Linsoul Aliexpress Store: https://ddaudio.aliexpress.com/store/2894006
Linsoul USA Amazon Store link: https://www.amazon.com/s?i=merchant-items&me=A267P2DT104U3C

Disclaimer:
The Kiwi ears Airoso Universal IEM has had a total of 5 days of burn-in.

Disclaimer:
I want to thank Kaitlyn of Linsoul for the love and the Kiwi ears Airoso Universal IEM review sample.

Disclaimer:
These are one person's ideas and concepts, your results may vary.

Equipment Used:
Sony WM1A Walkman DAP MrWalkman’s Firmware 4.4mm balanced and 3.5mm
Sony WM1Z Walkman DAP MrWalkman’s Firmware 4.4mm balanced and 3.5mm
Sony TA-ZH1ES DAC/AMP Firmware 1.03 in 4.4mm balanced
Electra Glide Audio Reference Glide-Reference Standard "Fatboy" Power Cord
Sony Walkman Cradle BCR-NWH10
AudioQuest Carbon USB
Samsung Phone 3.5mm
HiBy R3 II DAP 4.4mm
ifi Go blu Bluetooth Amplifier and DAC 4.4mm
ifi hip dac 3 Amplifier and DAC 4.4mm

Kiwi Ears Airoso - Kiwi Ears KE4, Now with Sparkles!​

Kiwi Ears has steadily built a reputation for crafting IEMs that strike a thoughtful balance between musicality and technical performance. With the Airoso, they introduce a new take on their tuning philosophy—one that refines their approach while adding a dose of energy and excitement.

While the KE4 leaned towards a deep, immersive bass experience with a neutral and smooth presentation, the Airoso takes a different route. It aims for a livelier, more engaging sound, with a dynamic tuning and a treble presentation that stands out.

But does this shift in approach translate to a well-balanced and enjoyable listening experience, or does it come at the expense of refinement? Let’s take a closer look.

Whats in the box? heres a quick unbox video of the Airoso.



Unboxing & Accessories
Kiwi Ears has alway kept things simple with the packaging. Inside the box, you’ll find:
• 1x Kiwi Ears Airoso IEM
• 1x Detachable Cable (0.78mm 2-pin, 3.5mm termination)
• 8x Pairs of Eartips (various sizes and shapes)
• 1x Carrying Case
• 1x User Manual

The inclusion of eight pairs of eartips is a thoughtful touch, ensuring users can fine-tune the fit and sound. The detachable cable is solid but fairly standard and thin for my taste—I’d recommend upgrading to a higher-quality cable if you’re chasing that last bit of performance.

Build & Comfort
The Kiwi Ears Airoso boasts a sleek yet rugged design that blends aesthetics with functionality. Its shell appears to be crafted from solid black resin, offering a smooth, contoured fit that conforms effortlessly to the ear. The faceplate, in contrast, features a raw-finished brushed titanium surface, giving the Airoso an industrial, almost modern minimalist appeal. Despite its robust appearance, the IEM remains surprisingly lightweight, making it comfortable for extended listening sessions.

True to Kiwi Ears’ reputation, the ergonomics are spot-on—the fit feels secure yet pressure-free, ensuring a snug seal without discomfort. This makes the Airoso an excellent choice for both casual and prolonged use. The flat 2-pin connector is a smart inclusion, offering durability and a secure connection while reducing strain on the socket over time.

The build quality is outstanding, striking a fine balance between durability and elegance. Every detail, from the choice of materials to the smooth finishing, reflects a premium standard. I also can’t help but appreciate Kiwi Ears’ industrial-inspired aesthetic, it’s bold, raw, modern and refreshingly subdued.

Sound Quality
Now, let’s get to what really matters—the Airoso’s sound signature. This IEM stands out with an engaging, dynamic, and refined presentation, striking a balance between depth, clarity, and energy. It delivers a deep, authoritative bass, articulate mids, and one of the best treble tunings I’ve heard from Kiwi Ears.

I think the reason why Kiwi Ears named this set The Airoso because it likely hints at its airy treble, which adds an expansive and open feel to the sound. The mids and highs almost give off an open-back-like presentation, creating a spacious and natural atmosphere, while the bass remains tight, powerful, and controlled, reminiscent of a closed-back design. This combination makes for a unique and captivating listening experience, blending openness with impact in a way that feels both immersive and well-balanced.


Bass – Deep, Controlled, and Engaging
The Airoso retains the deep, authoritative bass that made the KE4 stand out, but it’s more controlled and refined. There’s less bloat, more texture, and a faster decay, making the low end feel tight yet very powerful. Subbass digs deep with excellent rumble, while the midbass delivers punch and warmth without overpowering the rest of the sound.
Bass lovers will still find plenty to enjoy, but what sets the Airoso apart is how well it integrates with the mids and treble, it never overshadows the rest of the spectrum.

Midrange – Balanced and Natural
The mids strike a balance between clarity and musicality. Instruments sound natural and well-defined, with just the right amount of weight.

Male vocals sound rich, textured, and grounded, carrying a natural warmth that makes them feel lifelike. Female vocals, on the other hand, are expressive and lively, with a crisp articulation that allows emotions to come through effortlessly.

The upper midrange is energetic yet refined and smooth, giving vocals and instruments a sense of presence without veering into sharpness or sibilance.

Treble – The Star of the Show, The Air in Air-oso
This is where the Airoso sets itself apart. The treble is layered, detailed, and beautifully refined—it’s airy, full of micro-detail, and incredibly well-separated. It’s like hearing three different kinds of treble working in harmony, each adding something unique:
• Lower Treble: Clear and energetic, adding definition without harshness.
• Mid Treble: Detailed and transparent, bringing out subtle nuances in instruments.
• Upper Treble: Airy and expansive, extending beautifully without becoming fatiguing.
Despite this wealth of treble information, the Airoso never sounds overly bright or sharp. Kiwi Ears has somehow managed to extract exceptional detail while maintaining a smooth, natural tonality. It’s one of the best treble tunings I’ve heard from the brand, refined, open, and endlessly enjoyable.


Soundstage & Imaging – Expansive and Holographic
The Kiwi Ears Airoso scales noticeably with power, revealing more depth and refinement when paired with a capable source. With proper amplification, the soundstage expands beautifully, offering an impressively wide and holographic presentation. There’s a genuine sense of space, allowing instruments to feel naturally positioned rather than crammed together.

One of the standout aspects is the precise imaging, each element in a track is distinct and well-placed, making it easy to pick apart layers of a mix. This level of separation enhances the overall immersion, pulling you into the music rather than just presenting it to you.

What makes the Airoso even more compelling is its ability to balance technical precision with musicality. Unlike some analytical IEMs that can feel clinical or fatiguing over time, the Airoso retains a smooth, engaging character, ensuring that critical listening doesn’t come at the expense of enjoyment. It’s a rare blend of detail, depth, and emotion.

Drivability & Pairing
With an impedance of 15Ω and a sensitivity of 105dB, the Kiwi Ears Airoso isn’t particularly demanding in terms of power, it’ll run just fine off most portable sources, including smartphones, dongle DACs, and entry-level DAPs. However, to truly experience what it’s capable of, it benefits significantly from a higher-quality source.

Feeding the Airoso with a more powerful DAC or amplifier doesn’t just increase volume—it enhances dynamics, expands the soundstage, and refines imaging, creating a more holographic and immersive experience. The bass gains better control and texture, mids become more expressive, and treble takes on a more refined, airy quality.

For the best pairing, I’d recommend a neutral or slightly warm source—something that complements its tuning without over emphasizing any particular frequency. The Hiby R6 III DAP is an excellent match, providing clean power with a touch of warmth. If you prefer a desktop setup, the FiiO K11 R2R DAC/amp would be another fantastic option, adding a bit of analog smoothness while preserving detail and resolution. With the right setup, the Airoso truly comes even more alive, offering a sound that feels both expansive and intimate at the same time.

Conclusion – A Refined Yet Fun Hybrid IEM

The Kiwi Ears Airoso is an exceptionally well-tuned hybrid IEM that delivers deep, controlled bass, natural mids, and some of the best treble tuning in its class. It takes everything great about the KE4 and refines it, adding better control, enhanced layering, and an airier, more spacious presentation.
• Bass lovers will appreciate the depth and punch without bloat.
• Treble enthusiasts will love the detail, separation, and airiness.
• Those looking for an immersive, high-fidelity experience will be impressed by its holographic staging.
For those who want a fun yet refined IEM that scales beautifully with better gear, the Airoso is a fantastic choice. It’s clear that Kiwi Ears poured a lot of thought into its tuning, and the result is an IEM that doesn’t just sound good—it feels special.
If they named it Airoso because of how airy the treble is... well, that makes perfect sense.

Non Affiliated Link:

https://www.linsoul.com/products/ki...ZjwBDqCQmJODZh1c4DWXpQ0pQV7_qYKw1p_bsUCE--FNH