The Right Name

Ratings

Pros

• Exploiting the virtues of the drivers.
• Precise, fast bass with a remarkable amount of power and volume.
• Resolute, informative mids, with a good level of presence, neutrality in timbre and without being clearly analytical.
• Treble homogeneous, extended, airy, fine, delicate and with a good degree of energy.
• Three-dimensional note separation, generating a precise image and a wide stage in all three directions.
• Pleasant W-tuning and no peaks in any range.
• Very comfortable, snug fit and low weight, very suitable for long listening.
• The zippered case is always welcome.

Cons

• Although the build standard is good, the design is somewhat simple and not very eye-catching.
• Kiwi Ears have used the cable from the lower priced models.
• There is no balanced connection option.
• Although they come with three pairs of silicone tips, none of them are special, now that every brand is rushing out improved models.

Purchase Link

https://kiwiears.com/products/kiwi-ears-airoso

Link to the WEB

https://kiwiears.com/

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.
• Capsule 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.