Disclaimer
- Sound evaluation are kept neutral and does not include 3rd party accessories (ie; eartips, cable, reversible mods)
- The reviewed IEM is a sponsored unit by Kiwi Ears. Nevertheless, all opinions remain original ideas, there was zero influence from any 3rd party or external opinions throughout the review.
- No EQ or filter presets were used during the entire sound evaluation.
Overall Rating
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Cons |
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Introduction
Kiwi Ears in recent times has released numerous brand new IEMs and including their own headphone series which I have yet to personally try. Although I’m more into IEMs, I can’t deny that I’m not interested in trying their headphones, especially the Atheia which was their first full size planar magnetic headphones. That said, recently after the review of my Orchestra Lite. Kiwi Ears asked me whether I am interested in trying their brand new hybrid IEM, which so far if my memory serves me right the only current hybrid IEMs Kiwi Ears have were the highly-regarded Meta tuned Kiwi Ears KE4, that I covered a few months back. In my opinion, it was an excellent pair of IEMs although it was lacking in terms of technicalities and driver capabilities, especially the dynamic driver to deliver satisfying, high quality bass performance.
Regardless, we’re here not to talk about the KE4 anymore. With me in this review is the brand new Kiwi Ears Airoso, which means airy/windy/blowy in Spanish. The Airoso features a brand new 5 driver hybrid configuration that utilizes a single dynamic driver with LCP + PU diaphragm and four balanced armature units, which are not specified from which brands. The Airoso is available for purchase for $129 at Linsoul Audio or via Kiwi Ears official website which you can read the technical details further via clicking the hyperlink. With all that is done, let’s jump into the review of the Kiwi Ears Airoso!
Unboxing Experience
Kiwi Ears are known for their straightforward and minimal approach in terms of their packaging and the Airoso was no different as well. Starting from the outer cover of the box, we have the illustration of the IEMs itself and I love the graphic design on the box. It’s clean, minimal yet playful combined with the fonts Kiwi Ears have used, in a way that they arranged the “Airoso” letterings that resembles airflow. On the side of the box, are located the basic specifications about the IEM. Meanwhile, at the back there’s also an illustration but a smaller version of the front, alongside the details of the company. Simple, basic stuff, straight to the point done tastefully right from Kiwi Ears.
As we unbox further, Kiwi Ears have done slight alterations in terms of their product presentation inside the hard box for the Airoso. Usually, with most Kiwi Ears IEMs you’ll see lots of it came with cardboard panels you’ll have to pull out each one out of the box. This time, they have gone for a much simpler, and straightforward presentation. A small rectangular foam cutout to secure the IEMs and a cardboard flap to cover the rest of the package, reminds me of Simgot IEMs sort of presentation, the EA500-series to be exact.
So, inside the box you’ll be greeted with the Airoso itself and as we unbox further, there’s a hard case which features a newer design which is slightly taller allowing for larger storage capacity compared to the previous case. Users will find the stock cable inside the case, including accessories such as ear tips which come in three different colours but similar/exactly the same kind. So I was wondering, perhaps Kiwi Ears might have done better by inserting two options instead of three, as in one pack of generic silicones and the other one is their Kiwi Ears Flex ear tips.
Specifications
- Driver: 1 LCP + PU diaphragm dynamic driver, 2 balanced armatures (high), 2 balanced armatures (ultra-high)
- Impedance: 18 Ohms
- Sensitivity: 110dB/SPL
- Frequency Response: 20Hz-20kHz
- Cable: 4 core copper cable with 3.5mm to 2-pin (0.78mm)
- Nozzle diameter: 6mm
- Weight: 12g
Build and Comfort
After trying numerous in-ear monitors from Kiwi Ears, it can be said that most of their IEMs are comfortable, lightweight and yet feels rigid to withstand daily usage. Not including the Orchestra Lite I’ve recently reviewed though, due to an issue in regards to the lack of vent holes which causes internal pressure build-up. Fortunately, that was not the case I had with the Airoso, I find the IEM to be very comfortable due to its lightweight design, with the appropriate nozzle length and angle despite the nozzle width was slightly on the larger side measured at 6mm so those with smaller ears might have to take note. Although, the Kiwi Ears Airoso does not have an ergonomic ear hook design that grabs onto your conchae likewise with the KE4. It does not influence the overall wearing experience in a bad way, as it still fits nicely and firmly in your ears.
Similarly with most of their IEMs, the Airoso is made from resin similar to the one on the KE4 with a tiny pressure release vent placed just right before the nozzle. Meanwhile, the faceplate is made with metal that was meticulously done using a CNC machine which has an automotive, industrial inspired design as far as how it looks to me. The filleted edges of the faceplate still feels quite edgy, but thankfully not sharp or coarse by any means, there’s also a tiny cutout right next to the “Kiwi Ears” branding that works as an additional pressure release vent. Due to that, I could not hear any crinkling sound coming from the internals or any trouble to pull out the IEM easily with the new vent design. Overall, the build quality on this IEM is excellent in my opinion, it feels rigid with not a single loose part and won’t feel like it’ll break anytime soon.
Cable
Kiwi Ears have decided to downgrade the cable for the Airoso, compared to its more premium siblings such as the KE4 or even the brand new Aether. In fact, it is exactly the same cable that came with the Kiwi Ears Cadenza. I’m not particularly disappointed with it, perhaps it is one way Kiwi Ears could maximize the potential performance that can be invested into the Airoso without spending too much.
Nevertheless, the cable included for the Airoso was a basic 4 core wire that I assume is a typical OFC (oxygen-free copper) cable, insulated with a polyurethane (PU) material to protect the wires from elements. Overall, it is a decent cable, lightweight, flexible which makes it easy to wrap for storage and fairly resistant to tangling. Unfortunately, the cable for the Airoso does only come in a 3.5mm single-ended option but you can always swap it with a 3rd party cable, if you wish to have better aesthetics and ease of usage.
Test Equipment
- Local Hi-Res files > Astell&Kern SE100 M.Chat (Linear Phase Fast Roll-off Filter)
- Tidal (Master) + Local Hi-Res files via UAPP > Sony Xperia 1 V + DSEE Ultimate (ON), Dolby Atmos (OFF)
- Tidal (Master) + Local Hi-Res files via UAPP > Sony Xperia 1 V > Questyle M18i
- Tidal (Master) + Local Hi-Res files via UAPP > Sony Xperia 1 V > Kiwi Ears Allegro Mini
- Tidal (Master) + Local Hi-Res files via UAPP > Sony Xperia 1 V > MUSEHIFI M3 II
Power Requirements
Rated at an impedance of only 18 Ohms and combined with the 110 dB/SPL, the Kiwi Ears Airoso were an efficient pair of in-ear monitors that can be easily powered through small devices and scales well with more powerful devices such as portable DAC/AMPs. Additionally, due to the high sensitivity the Airoso could transmit white noise or hissing sound into the background, which could be emitted from sources that have high noise levels such as the Kiwi Ears Allegro Pro which I have reviewed quite recently.
Apart from that, end-users should not be worried about the required output power to run the Airoso. I’ve tested it through the Kiwi Ears Allegro Mini and VE Odo and needed only between 5-7/30 volume adjustments on my Sony Xperia 1 V to reach the comfortable loudness for my personal preference. On more powerful devices such as the Questyle M18i, it took me 8-10/60 on low gain settings, single-ended. Meanwhile, driven through my Astell&Kern SE100, it took me to raise the volume up to 35-40/150 to achieve my desired loudness.
Initial Impression
The Kiwi Ears Airoso has undergone burn-in phase for at least 48 hours prior to sound evaluation. Throughout the analysis, I paired up the Airoso with a neutral source, the A&K SE100 on Linear Phase Fast Roll-off Filter chosen given that it’s the most natural sounding filter compared to default. Triple-flange eartips are used as default eartips throughout the sound evaluation. Bonus test tracks used can be found down at the end of this review.
The Kiwi Ears Airoso is an exciting, well-balanced sounding IEM with an overall warm, bodied bass that gradually slopes into the lower midrange which gives a slight colouration into the midrange. Higher frequencies starting from the upper-mid region all the way towards the higher treble were lively, with very good presence in my opinion without coming across that I would consider it as harsh or coarse to my surprise. Despite having said that, there are noticeable irregularities that’s translated via peaks and dips between the 5kHz and up to 10kHz. Kiwi Ears did mention the existence of what they refer as “precision crossovers” being implemented inside the Airoso, to control the drivers to individually reproduce a specific spectrum of frequencies.
Moreover, the slightly elevated upper-mid frequency allows the Airoso very much reminds me of the more premium Kiwi Ears KE4, albeit the Airoso appears to be slightly more highlighted. This may be due to the brighter timbre of this IEM. Additionally, due to the emphasized peak at an approximate 13k-14kHz. It made the Airoso sound pleasantly airy and open, which made the soundstage on this IEM sounded quite surprisingly very spacious.
Low Frequency (Bass)
Low frequencies on the Kiwi Ears Airoso can be described as warm, exciting and now strikes slightly harder than the much premium KE4. Although the Airoso is still something I would not consider as a bass head worthy pair of IEMs, it might still be an appealing option for those who appreciate high quality bass or if you prefer a slightly Harman-esque tuned bass in a Meta tuning. Sub-bass on the Airoso can be described as rumbly, fairly textured with good definition, which I consider as an upgrade from the Kiwi Ears KE4 which I find too light, and blunt for my personal preference. As per usual, I tested the Airoso with my standard bass track, Hollow (16-bit Remix) – Björk and the Airoso were surprisingly has good depth being able to reach below 60Hz, while presenting the low-bass rumbles cleanly with a groovy rumbling effect that was nicely textured.
I’m not entirely sure whether Kiwi Ears used a brand new dynamic driver for the Airoso or might just be due to the tuning as one could refer to via the diagram above that shows the Airoso does have a slight elevation on sub-bass and into lower midrange. Though the mid-bass slams still have that pillowy effect, it does hit noticeably solid and harder now, with more authority compared to the ones that are in the KE4. I would describe it more towards a thick, quite hefty “thud”, followed by a longer transient which enhanced the bass to sound more dynamic and immersive allowing bass notes to linger slightly longer. That said, I could not hear any difference in terms of speed and delivery, especially when played through tracks such as Hunter – Björk as the Airoso could timely render each bass slams. Although due to the slightly longer transient, it does cause some melding.
Middle Frequency (Mid)
Midrange on the Airoso offers a neutral sound signature with a slightly warm timbre. As I could hear the tonality in vocals and some stringed instruments such as acoustic guitars had a slightly added colouration. Apart from that the midrange is also combined with a smooth upper-mid, yet it offers very good clarity which enhances vocal articulations without coming across as intense.
To my surprise, the Airoso were capable of rendering textures in vocals such as late Layne Staley’s iconic grunge vocals in Down In A Hole (Unplugged) – AiC. Though it was not insanely detailed as higher-end IEMs could offer, to me it was still an impressive feat in my opinion. Additionally, although on paper the Airoso might seem a bit Harman-ish in the mids, I do not find these to be recessed at all but rather forward with a fairly strong presence. Hence, vocals were nicely highlighted and separated from other elements within the mids.
High Frequency (Treble)
Treble on the Airoso as expected from the name, was airy which provides a pleasant ambience in the soundstage. Furthermore, the Airoso is slightly on the brighter, livelier side yet at the same time smooth and suitable even for long hours of listening despite the peaks and dips on the treble. Sound of hi-hats and crashes sounded crisp, detailed and impressively natural without coming across as sibilant, equally the same with vocals. The pronunciation of “s” and “t”, for example in the track Underwater Love – Soulperfreesia sounded slightly on the sharper but not in a bad way and free from sibilant, which most likely due to the dip at 5kHz.
Technicality
In the technical department, one of the strongest points of the Kiwi Ears Airoso was its capability to render a large, spacious soundstaging primarily in terms of width size which was wider compared to its depth, which for me felt quite mushed together. It feels pleasant, nicely airy while resonance and reverberations dissipate naturally due to the pressure vent that is located on the faceplate. Spatial imaging on the other hand was decent, slightly poorer compared to the KE4 which I rated average in my KE4 review if I’m being totally honest. Detail retrieval on the Airoso was also quite impressive in my opinion, it could render high level details and low level details without any problems. However, when it comes to resolution the Airoso fell quite short as subtle nuances sounded blurrish, blunt and lacking in definition.
Separation and layering on the Airoso were average in my book, the IEM does work well with genres or songs with limited elements since the Airoso tends to get congested and meld. Lastly for the dynamic range test for the Kiwi Ears Airoso is rated at average. Utilizing the Ultimate Headphone Test – ABYSS Headphone dynamic range test as a reference. In short, a sample sound of a drum and a bell are played simultaneously as much as 7 counts, but only the sound of the bells will become quieter. Hence, from a scale of 7 counts, Airoso was able to produce an audible 5 out of 7 counts.
Comparison(s)
Kiwi Ears KE4
Comparatively, both of these IEMs are quite similar sounding but with a noticeable difference. If I could explain it in short, if you think that the KE4 was a bit too boring or safe, perhaps maybe a bit lacking in the treble region in your opinion. Then, the Airoso is essentially a much more exciting, livelier version of the KE4. I’ve said it in my previous review, that theKE4 could need a slightly brighter treble, just by a couple 2-3dB to make it slightly more engaging and the Airoso is essentially that.
For more in-depth details, bass on both IEMs are equally snappy and responsive. However, the KE4 sounded much softer and wooly in delivering bass punches and slams which was my main complaint. That said, the KE4 has faster decay which causes bass transients to be slightly shorter compared to the Airoso. That said, the isobaric dynamic drivers inside the KE4 provided an immersive bass experience. Midrange timbre was a tad warmer and richer on the KE4 but at the same time slightly muddy due to the elevation in the lower-mids. Vocal presentation on the KE4 sounded slightly recessed compared to the Airoso. Moving towards the treble was the most noticeable difference between the two. As KE4 was more suitable for those to prefer smoother, inoffensive treble that is suitable for long hours of listening but it can be a tad splashy.
Technically, the KE4 is slightly superior in terms of resolution however, falls slightly short to the Airoso due to the accentuated treble. Soundstage also sounded a lot more intimate and spatial imaging was slightly more precise on the KE4. That said, both IEMs have average dynamic range which I ran through the test and it scored a 5 out of 7 bell counts.
Eartip Combination(s)
Pentaconn Coreir Alloy
The Coreir brings a little bit more clarity in the midrange and slightly leaner lower-mids due to the wide bore design of the Coreir which lessens the bass quantity by a slight amount and fixes the melding aforementioned. However, bass slams feel a tad more rounded and defined rather than a flat “thud” sound. Treble was not quite affected as far as this pairing goes, though I did notice the soundstaging became slightly less airy. Nevertheless, the size and width of the soundstage remains pretty much the same in my opinion (YMMV).
E Pro EP01
A decent pairing in my opinion, the Airoso sounded almost identical to the KE4 when paired with the EP01. Albeit, there are subtle differences such as a heftier, boomier bass slam. Midrange is a tad warmer to the original stock yet without reducing the clarity in the lower-mids. Soundstage on these turned into an oval sort of shape, though it does not affect the airiness in any sort. However, the treble became somewhat similar to what I experienced with the KE4, which was a tad splashy but the Airoso since it alread has a brighter treble to begin with I could still hear very good presence in that mentioned region.
Purchasing Links and Where to Get?
Kiwi Ears Official Website (non-affiliated):
https://kiwiears.com/products/kiwi-ears-airoso
Conclusion
Kiwi Ears has outdone themselves with the brand new Kiwi Ears Airoso and I can’t say that I’m not impressed considering that they can achieve a similar result on their KE4 BUT better and cheaper with the Airoso. I also love the fact that Kiwi Ears have changed the hard case to a slightly taller one that allows for larger storage space, which was also one of my complaints and among other reviewers too. However, I do wish Kiwi Ears would place better inclusions next time such as better ear tips since they have the Kiwi Ears Flex which in my opinion are a great pair of eartips for adding bass quantity and quality without sacrificing treble presence and extension when compared with other bass enhancing ear tips.
Having said that, the Kiwi Ears Airoso is an excellent alternative especially if you wish the KE4 has a slightly more enhanced treble, larger and airier soundstaging combined with a cleaner midrange. Which in my opinion, has a better lower-mid clarity compared to the KE4 that can get quite muddy with certain ear tips. Combine this all at $70 much cheaper than the KE4, and perhaps the extra balance you could get the Kiwi Ears Flex ear tips to go with it. Well, that marks up the end to my review of the Kiwi Ears Airoso and hope to see you all in the next one!
Additional Test Tracks
Can You Stand The Rain – Boyz II Men 44.1kHz
Money For Nothing (Explicit) – Dire Straits 44.1kHz
A Poem Titled You – TAEYEON 44.1kHz
Anesthetize (Live) – Porcupine Tree DSD256
Vermilion – Slipknot 44.1kHz
Kanade – SUKIMASWITCH 44.1kHz
La vaguelette (Original Game Soundtrack) – HOYO-MiX 44.1kHz
Rhythm – Jamey Haddad, Lenny White; Mark Sherman 44.1kHz
Kimigatame (When Suara Meets DSD 11.2Mhz) – Suara DSD11.2MHz
Just Coolin’ – Art Blakey 192kHz
Automatic – Hikaru Utada 44.1kHz
In My Room – Hikaru Utada 44.1kHz
Colors (Live in Studio) – Black Pumas 192kHz
Timbres – Yosi Horikawa 44.1kHz Misguided Ghosts – Paramore 44.1kHz
