Astell & Kern
XIO In Ear Monitors
$3,000.00 USDFeatures
TRUE ISOBARIC Dual Dynamic Drivers - Advanced bass and mid-range performance
Multi-BA Driver Array - Dedicated mid-frequency and high-mid frequency balanced armature drivers
Premium 904L Stainless Steel - Diamond-like carbon (DLC) coated housing
Apex Module - Tunable acoustic technology
0.78mm 2-Pin Socket - Standard detachable cable connection
Video
What's in the Box?
Warranty
Introducing the XIO
Experience the technical precision and musicality of the Astell&Kern XIO premium in-ear monitors, born from the collaboration between luxury audio pioneers, Astell&Kern and 64 Audio. The XIO IEMs blend premium engineering with artistic sensibility, delivering an unparalleled listening experience that sets new standards for high-end in-ear monitors.
The XIO IEMs are designed for music lovers and discerning audiophiles who demand nothing less than perfection. With 10 hybrid drivers, proprietary 64 Audio technology like tia waveguide, and crafted aesthetics, the XIO IEMs are an incredible portable audio solution delivering years of happy listening. The XIO goes beyond simply playing music, it shapes sound into a tangible experience.
"XIO boldly opens a new chapter in the evolution of high-end in-ear monitors. It goes beyond simply reproducing sound – it embodies our philosophy of sculpting sound itself. By combining mechanical perfection with musical sensibility, XIO creates value that exceeds expectations."
– Vitaliy Belonozhko, 64 Audio Founder and CEO
10-Driver Hybrid System: Uncompromising Audio Performance
The Astell&Kern XIO IEM is meticulously engineered both inside and out. Its advanced hybrid system, featuring 10 high-performance drivers, is finely tuned with a 4-way passive crossover to ensure every frequency is in perfect harmony. This precise tuning delivers a realistic sense of depth and a rich, spacious soundstage.
Dual dynamic drivers in a TRUE ISOBARIC configuration deliver powerful, controlled bass, while multiple balanced armature (BA) drivers are responsible for the XIO's precise mid and high-frequency reproduction. This advanced driver array creates an unforgettable listening experience with imaging precision that rivals high-end headphones.
Tia Waveguide
The tia Ⓡ driver is designed with a direct-radiating structure that eliminates the traditional sound tube, enhancing the delicacy of high frequencies. This design minimizes damping and distortion, while the precisely positioned driver, together with a custom waveguide system, delivers a deep sense of space and airy, detailed highs.
BA Driver Manifold Assembly
The mid and upper-mid frequencies are powered by six and one balanced armature drivers, respectively, delivering smooth transitions and rich texture. Vocals, instruments, and their unique harmonic details are rendered warm and clear, creating a natural and well-balanced sense of space within the soundstage.
True ISOBARIC Dual Dynamic Driver
The TRUE ISOBARIC structure features two dynamic drivers perfectly synchronized within an acoustically neutral coupling chamber, enabling precise control. This design delivers bass with exceptional depth and density, as well as powerful sound impact—surpassing what is typically possible with conventional IEMs.
Breakthrough Technologies in Premium IEMs
Much of the XIO IEM's performance is attributed to 64 Audio's proprietary technologies, Tia, Apex, and LID.
Tubeless In-Ear Audio (Tia) is a patented IEM design that minimizes resonance and distortion, delivering clear and vivid sound to your ears. The tia system consists of the tia driver, single-bore design, and acoustic chamber, and the XIO adopts the tia driver and single-bore structure to capture the pure essence of sound.
Apex (Air Pressure Exchange) is a patented venting system that naturally releases pressure from the sealed ear canal while maintaining excellent noise isolation. This technology reduces listening fatigue during extended sessions, providing a much wider, more realistic soundstage.
A part of the Apex venting system is 64 Audio's Apex Modules, included with the XIO. The M15 module, standard with the XIO, is specially designed with a DLC coating on 904L stainless steel, making it a unique apex solution exclusive to this model. The Apex modules
Linear Impedance Design (LID) is a patented circuit that compensates for nonlinear resistance between drivers, ensuring consistent sound quality regardless of changes in the output impedance of the source device. This provides the XIO with a stable sound signature and accurate frequency response at all times.
Internal Structure of the XIO
- tiaⓇ Waveguide
- 0.78mm 2-pin Socket
- Diamond-Like Carbon (DLC) Coated 904L Stainless Steel
- Mid Frequency BA Driver
- TRUE ISOBARIC Dual Dynamic Driver
- Diamond-Like Carbon (DLC) Coated 904L Stainless Steel
- Apex Module
- High-Mid Frequency BA Driver
- Driver Housing
- tiaⓇ High Frequency Driver
Premium Materials and Craftsmanship
The XIO's exceptional quality begins with carefully selected materials that ensure both sonic excellence and lasting durability. The XIO's shell is crafted with precisely machined 904L stainless steel–a material harder and more challenging to work with than standard stainless steel, but incredibly durable for an IEM–and is finished with a luxurious black DLC (Diamond-Like Carbon) coating for premium texture. The faceplate exhibits Astell&Kern’s design heritage, projecting a three-dimensional and elegant presence through deep shading and delicate reflections.
The included premium Litz Cable features UP-OCC (Ultra Pure Ohno Continuous Cast) copper conductors with silver plating for enhanced signal transmission and reduced electrical resistance. The four-core cross-braided design provides both durability and aesthetic appeal, while the exceptionally low 0.29Ω impedance maximizes electrical efficiency. The cable terminates in secure, reliable 0.78mm 2-pin connectors that ensure optimal signal transfer and long-term reliability.
Astell&Kern XIO IEMs Review: The Musical Collab Audiophiles Have Been Waiting For
Read Time: Approx. 16 min.
TL;DR
- Premium Collaboration at $3,000: A premium collaboration between Astell&Kern and 64 Audio at $3,000, combining both companies' expertise in audio engineering and design philosophy
- Advanced 10-driver Hybrid System: Features TRUE ISOBARIC dual dynamic drivers, 6 mid-frequency BA drivers, 1 high-mid BA driver, and 1 TIA high-frequency driver with a 4-way passive crossover for comprehensive frequency coverage
- Ultra-Premium Construction: Built with precision-milled 904L Stainless Steel housing and black LDC coating, offering exceptional durability and luxury aesthetics
- Rich, Musical Sound Signature: Delivers dynamic, full-bodied sound with punchy bass, lush midrange vocals, and airy highs
- Comprehensive Accessory Package: Includes 4 apex modules, premium leather case, multiple ear tip varieties, silver-plated UP-OCC copper Litz cable, and professional-grade accessories like cable clips and cleaning tools
When Audio Giants Collide–Astell&Kern x 64 Audio's $3k Masterpiece
When two hi-fi industry leaders collaborate, magic happens. At $3,000, the Astell&Kern XIO In-Ear Monitor combines 64 Audio's renowned IEM engineering–known for universal designs that fit like customs–with Astell&Kern's premium materials and proven audio expertise.
Perfect for audiophiles seeking musicality, resolution, and versatility across all genres, the XIO IEM delivers flagship-level performance through its 10-driver configuration and multiple patented 64 Audio technologies. Crafted with durable 904L stainless steel and meticulous attention to detail, the XIO sits in a league of its own, offering listeners a refined sonic experience in a breathtaking package.
If you thought audio nirvana was something of fairytales and hi-fi forums, you clearly haven't met the XIO.
Astell&Kern XIO IEMs Review: The $3K Dream 64 Audio Collab Worth The Hype
PROS
- 64 Audio signature styling and comfortable fit
- Dynamic, Rich, Full-bodied Sound
- Fantastic pairing with Astell&Kern DAPs like the SP4000 & SP3000M
CONS
- Shell coating is a fingerprint magnet
Design
The Astell&Kern XIO IEM sports 64 Audio's signature styling and kidney-shaped housing. 64 Audio has cracked the code for creating the perfect universal IEM that fits as if it were made for your ears and no one else's. The kidney bean housing complements our natural ear shape perfectly, so you can achieve a comfortable fit and seal without any problems.
The construction of the IEM itself is high-end and ultra-premium. The exterior, constructed from precision-milled 904L Stainless Steel, is a unique choice, one that's not typical of an earphone. We've seen Astell&Kern use this material in its DAP construction, and it's praised for its durability and corrosion resistance, so I'm not surprised to see that come into play here. Compared to traditional ultra-lightweight aluminum shells, the XIO feels denser but more durable. They're not heavy in any way, shape, or form! From the second you pick them up, you can tell there's a very high level of craftsmanship and quality put into these IEMs.
Each shell is finished with a luxurious black DLC (Diamond-Like Carbon) coating that gives it an ultra-shiny finish. 64 Audio and Astell&Kern mark each IEM with their seal, placing the AK logo on the left faceplate and 64's on the right. Last thing you'll find on each IEM is 64 Audio's m15 Apex Module, which comes pre-installed and is one of four included with the IEMs. More on that magic in the features section!
Arguably one of the best perks about purchasing a 64 Audio IEM (in this case, an Astell&Kern x 64 Audio IEM) is the plethora of included accessories. There is only one other IEM manufacturer–maybe two if I think hard–that includes as much swag and accessories as 64 Audio. They go well beyond the basics. Along with the standard cable, you'll find a cleaning tool, a cable clip, a premium leather case, and a variety of specially-designed ear tips on a tip holder (SpinFit foam ear tips, TrueFidelity foam tips, and silicone ear tips)—plus a 64 Audio sticker for good measure. The cable clip is a particularly thoughtful touch, commonly used by audio professionals with custom IEMs to prevent the cable from getting caught and potentially damaging the IEM jacks. The included cleaning tool helps remove build-up and debris that could otherwise reach the IEM driver, ensuring optimal performance over time.
Completing the masterpiece that is the XIO is a dedicated silver-plated UP-OCC copper Litz cable with a 2-pin socket and 4.4mm balanced termination. The four-core cross-braided cable ensures excellent noise shielding, transparent signal transmission, and, with an ultra-low impedance of just 0.29 ohms, maximizes electrical efficiency when paired with any high-quality headphone amp or DAP.
Sound
For the ultimate synergy, it only felt fitting to pair the XIO IEMs with an Astell&Kern DAP. And because Astell&Kern has produced several great DAPs over the last year, I couldn't pick just one. First, the SP4000, then the SP3000M, and lastly the PD10.
The SP3000M and SP4000 possess Astell&Kern's signature sound quality that's resolute, detailed, and accurate. The PD10, on the other hand, is the wild card with a richer, more dynamic sound quality that complements the XIO's rich, full-bodied sound.
From the moment I connected the XIO IEMs to the Silver Dragon IEM Cable and SP4000 DAP, I knew this was a 64 Audio-engineered IEM. Astell&Kern and 64 Audio are two companies that understand the importance of sound quality in a component. You would think that this is a universal philosophy among all hi-fi manufacturers, but that's not always the case. Some manufacturers prioritize design over internal tech, and others prioritize squeezing as much tech into a product as possible to classify it as "cutting-edge." But just like making homemade sauce, it's a delicate balance. A little more salt, a teaspoon of baking soda, and a whole lot of patience until it's just right. The XIO IEM is the perfect Sunday sauce, featuring AK and 64's top ingredients.
The XIO IEM delivers a dynamic, rich, and incredibly musical sound that leaves you wanting more. Whether it's EDM, hip-hop, classic rock, or bossa nova jazz that's your pleasure, the XIO replicates it to its fullest potential. The Balanced Armature drivers lend great texture and visceral elements in the low-end. And speaking of low-end...wow! Punchy, quick, and bold–but never bloated or heavy.
The dynamic range and soundstage are the most impressive aspects of the XIO. Slower, vocal-centric tracks like Been Like This by Doja Cat are rich and full of life. Vocals are lush in the best way possible. The emotion behind Doja's lyrics is tangible, as if I could reach out and grab the words as they float by. Then, in a split second, I'm thrown into the next track, a fast-paced EDM-style pop hit (Electropop) from Demi Lovato.
Within the last five years, EDM has taken off, and it's slowly crept its way into pop radio hits. Every artist under the sun has played around with synth-heavy beats, and the newest to take a stab at it is Demi Lovato with her single Fast. I'm an EDM fan, and I personally enjoy euro-club style hits. They're fast, punchy, and full of energy, and not every IEM can handle the demands of those tracks.
The first 15 seconds of Fast start rather tame with a very basic synthesizer beat behind Lovato's vocals. As the chorus approaches, things start to ramp up, and the XIO really starts to shine. The beat becomes bolder with a mid-bass energy that's articulated as a visceral thump tunneling its way through my ear canals. Once the chorus hit, the XIO IEMs kicked into overdrive, showcasing what they're truly capable of. What's that, you ask? Articulation, energy, and musicality–all wrapped up in a single pair of IEMs that had me head-bumping in my chair at 3 p.m. on a Wednesday.
Finding an IEM that does one thing really well is easy, but finding one that does a lot of things great is like winning the jackpot–you might slap yourself a time or two to make sure you're not dreaming. The XIO IEM is the result of Astell&Kern and 64 Audio's passion for creating authentic listening experiences. It's full of character and musicality with a great sense of realism. You can close your eyes and drift off to a blissful state where the lines between reality and fantasy are crossed. Detail and articulation are maintained and executed with precision in tracks like Somehow It's Been A Rough Day, where if you listen just close enough, you can hear the clanking of silverware and conversation in the background of the first few seconds.
Quick attack when needed. Rich, almost lush vocals–especially from female artists. The highs are airy and detailed, and the soundstage is spacious enough to transport you to the very seat you sat in when you saw that artist live in concert for the first time. If I had any grievances, they would be aired, but there are none. The XIO IEM is fit for every type of listener.
XIO vs. Volür
Since the release of the XIO IEMs, there's been quite a bit of talk among audiophiles asking how they compare to the Volür IEMs from 64 Audio. While both IEMs are musical and deliver a rich, full-bodied sound, their main difference lies in the low-end. The Volür's low-end sports slightly more rumble and density than the XIO. Songs with a deep, impactful sub-bass are big and bold on the Volür, and more defined and punchy on the XIO.
Where the Volür delivers you an "in-your-head" style sound quality that envelops you and throws you right into the middle of the action, the XIO places you in the orchestra pit of an amphitheatre, perfectly positioned in the middle.
Been Like This
By Doja Cat
(Planet Her)
Girl
By The Internet
(Ego Death)
Fast
By Demi Lovato
(Fast)
Somehow It's Been A Rough Day
By Ai Kuwabara
(Live at Blue Note Tokyo)
Features
Configuring multiple drivers and innovative technology into a tiny IEM seems like a near-impossible task, but for 64 Audio, it's as easy as riding a bike. 64 Audio has an established reputation as a company willing to, and fully capable of, pushing the envelope as far as it will go. From the impressive 18-driver configuration that is the U18t to the simpler, single-driver Solo IEM, 64 Audio has done it all–and some.
The XIO IEM features an advanced hybrid system with ten meticulously tuned drivers and a 4-way passive crossover. Looking at detailed specs, 64 Audio's Tia Waveguide, TRUE ISOBARIC Dual Dynamic Drivers, and Multi-BA Driver Array are at the helm of the XIO's hybrid system.
The Tia driver is 64 Audio's secret weapon and their claim to fame for manufacturing tubeless IEMs. It uses a direct-radiating structure that eliminates the traditional sound tube, enhancing the delicacy of high frequencies. This design minimizes damping and distortion so you can enjoy a deep sense of space and airy, detailed highs.
The mid and upper-mid frequencies are powered by six and one balanced armature drivers, delivering smooth transitions and rich texture in the midrange. Vocals, instruments, and their unique harmonic details are rendered warm and clear, creating a natural and well-balanced sense of space within the soundstage. The TRUE ISOBARIC structure features two dynamic drivers perfectly synced within an acoustically neutral coupling chamber, enabling precise control. This design delivers bass with exceptional depth and density, as well as powerful sound impact.
Supporting technology inside the XIO IEMs include 64 Audio's proprietary Linear Impedance Design (LID), Air Pressure Exchange (apex), and Tubeless In-Ear Audio (tia) design. The Tia system is a patented IEM design that minimizes resonance and distortion, delivering a clear and vivid sound quality. This system consists of the tia driver, single-bore design, and acoustic chamber.
apex is a patented venting system that naturally releases pressure from the sealed ear canal while maintaining excellent noise isolation. This reduces listening fatigue during extended sessions and provides the XIO's wide, realistic soundstage. Lastly, LID is a patented circuit that compensates for nonlinear resistance between drivers. This ensures consistent sound quality regardless of changes in the output impedance of the source device (be it a DAC, DAP, or Headphone Amplifier).
Apex Modules
Included with the XIO IEMs are 64 Audio's state-of-the-art Apex Modules. These tiny interchangeable modules afford you the luxury of having multiple IEMs without purchasing more than one. 64 Audio has four apex modules: m20, mX, m15, and m10 included with the XIO.
The apex modules allow you to adjust pressure relief, noise isolation, bass attenuation, and mix width. The m20 module comes standard with most of 64 Audio's IEMs, and retains the most low-frequency energy and tight center imaging with roughly -20dB of noise isolation. The mX achieves the most open and transparent audio experience. It reduces ambient noise isolation to -10dB and transforms the IEMs into a "mastering-grade tool" with a very resolved sound signature.
The m15 module features a combination of dual ambient ports and modified internals to achieve -15dB isolation. It allows for slightly more ambient sound than the m20 and helps tame the bass. Lastly, the m12 module provides -12dB isolation, making it a good choice for listeners who feel that the bass drop between m15 and mX is too drastic. It's the perfect choice for tracks where the bass response is just slightly overpowering the rest of the spectrum.
Want to enjoy some classical compositions? Switch out the m15 for the mX module. Not getting the instrument separation you desire? Switch to the m20 module. Need to tame the bass response? The m12 module can do the job. It's that easy. No frills, no fuss.
Dragon Cables
With a rich, full-bodied sound and punchy, yet impactful bass response, the XIO IEMs paired best with the Silver Dragon IEM Cable. The Silver Dragon tamed the low-end on tracks with slightly too much sub-bass slam for my liking. It maintained the airy, detailed highs the XIO delivers while refining any borderline sibilant notes from string instruments.
Our HiFi Audio Dragon Cables bring out more of what you love in your music and audio gear. If you love your headphones but wish they had a bit more top-end sparkle - a Silver Dragon Headphone Cable would be a great option. If your USB cables keep dying - as many stock cables do - then check out our quality USB Audio Cables. We say time and time again that materials matter, and our audio cables and custom geometries actually help to bring out those desired properties in your gear and music. We make tons of custom options for our customers so that you can get the right HiFi Audio cable for your exact needs. If you have any questions feel free to Contact Us and we'll be more than happy to help.
Verdict
At $3,000, the Astell&Kern XIO IEMs deliver a dynamic, rich, and incredibly musical sound quality that leaves you wanting more. Whether you're a seasoned audiophile seeking endgame IEMs or are ready to experience true high-fidelity sound, the XIO delivers an emotional and technically precise listening experience across every genre. The visceral bass response, emotive vocals, and realistic sound reproduction breathe life into any song.
Built with durable 904L stainless steel and a 10-driver hybrid system, the XIO embodies Astell&Kern's premium design philosophy and 64 Audio's driver expertise. Pair them with our Silver Dragon or Bronze Dragon IEM Cables to further enhance their already impressive tonality. The Silver Dragon IEM Cable is our most resolute cable with best-in-class detail retrieval, making it the perfect choice for jazz, classical, and vocal-centric songs. For those who enjoy high-energy genres like Rock, EDM, or Pop, the Bronze Dragon's UP-OCC copper and silver will do the trick. The Astell&Kern XIO IEMs don't just meet the hype–they exceed it.
Featured Products
Related Videos
Silver Dragon IEM Cables Explained
Our Top 5 64 Audio IEMs & Why We Love Them
Astell&Kern SP4000 Review: Full Android DAP & Flagship Sound
What's in the Box
· XIO Universal In-Ear Monitors
· 64 Audio Premium Leather Case
· TrueFidelity Foam Ear Tips (S, M, L)
· SpinFit Silicone Ear Tips (S, M, L)
· Silicone Ear Tips (S, M, L)
· Cleaning Tool
· Cleaning Cloth
· Cable Clip
· 4.4mm Silver Plated UP-OCC Copper Litz Cable
· Apex Modules: m20 (Silver) Special m15 (904L Stainless steel with DLC Coating) m12 (Gold), mX (Black)
Specifications
Model: XIO
Material: 904L Stainless Steel with DLC (Diamond-Like Carbon) Coating
Cable: 0.78mm 2-pin, 4.4mm Silver Plated UP-OCC Copper Litz Cable
Driver Configuration:
TRUE ISOBARIC Dual Dynamic Driver
6x Mid Frequency BA Drivers
1x High-Mid Frequency BA Driver
1x TIA® High Frequency Driver
Crossover: Integrated 4-way Passive Crossover
Special Features: TIA Waveguide technology, Apex Module, 0.78mm 2-pin socket
Frequency Response: 5Hz-22kHz
SPL: 103dB @ 1 kHz, 1mW
Impedance: 6.3 ohms @ 1 kHz
| Parameter | Specification |
|---|---|
| Physical Specifications | |
| Model | XIO |
| Material | 904L Stainless Steel with DLC (Diamond-Like Carbon) Coating |
| Cable | 0.78mm 2-pin, 4.4mm Silver Plated UP-OCC Copper Litz Cable |
| Technical Specifications | |
| Driver Configuration | TRUE ISOBARIC Dual Dynamic Driver 6x Mid Frequency BA Drivers 1x High-Mid Frequency BA Driver 1x TIA® High Frequency Driver |
| Crossover | Integrated 4-way Passive Crossover |
| Special Features | TIA® Waveguide Technology Apex Module 0.78mm 2-pin Socket |
| Audio Specifications | |
| Frequency Response | 5Hz - 22kHz |
| SPL | 103dB @ 1kHz, 1mW |
| Impedance | 6.3 ohms @ 1kHz |
