Astell&Kern AK UW100 review: Seriously great sound

Astell&Kern AK UW100

MSRP $299.00

“Astell&Kern lives up to its reputation for top-notch audio quality.”


  • Excellent sound quality
  • Very good sound isolation
  • Bluetooth multipoint
  • Wireless charging
  • Wear sensors


  • Poor call quality
  • No active noise cancellation
  • No IPX rating for water resistance

If you want a reliable set of wireless earbuds with decent sound, good battery life, and even active noise cancellation (ANC), you’ve already got tons of great options. But for a smaller subsection of buyers — often referred to as audiophiles — “decent” sound simply isn’t good enough. For these folks, only the best will do, and Astell&Kern (A&K) thinks its first wireless earbuds — the $299 AK UW100 — will make them happy. They’ll be available on April 11, 2022, with pre-orders beginning March 28.

A&K certainly has the engineering bona fides to pull it off. The Korean audio brand has a loyal following among enthusiasts thanks to its products’ unique designs and high-quality components. But it faces stiff competition from companies that now have years of experience producing wireless earbuds, including Sony, Sennheiser, and Master & Dynamic. Will A&K knock it out of the park on its first at-bat, or does it still have work to do? Let’s check these earbuds out.


Astell&Kern AK UW100 earbuds seen next to the company's SR25 portable media player.Astell&Kern AK UW100 earbuds seen next to the company’s SR25 portable media player. Simon Cohen / Digital Trends

A&K’s design language uses what can best be described as sharp, angled polygons. Its line of portable media players and headphone amps like the SR25 and Acro CA1000 are good examples of the way the company uses aluminum and glass and brings them together with radically beveled and chamfered edges. The UW100 attempts to echo this aesthetic while still incorporating the smooth and soft curves you need to make a set of earbuds comfortable enough to wear for long periods of time.

A&K has gone to a lot of trouble to make sure these earbuds live up to the lofty expectations of the audiophile community.

The result is a fairly large, rounded-pentagonal earbud that is instantly recognizable as an A&K design, just not quite as sculptural as its other products. It’s a compromise, but I’d argue it’s mostly a successful one. In terms of size, the UW100 are about as big as Sony’s WF-1000XM4, which puts them among the largest group of earbuds — far bigger than Apple’s AirPods Pro or Jabra’s Elite 7 Pro.

The Astell&Kern AK UW100 charging case sits next to the charging cases for Sony's WF-1000XM4 and Jabra's Elite 7 Pro.Astell&Kern AK UW100 (back) Sony WF-1000XM4 (middle), and Jabra’s Elite 7 Pro. Simon Cohen / Digital Trends

Their wireless charging-capable case is equally big — too big, in fact — to be what I’d call pocketable. Somehow, Sony was able to make a much smaller case for the 1000XM4. The UW100’s case lid has a very strong magnet, so there’s no need to worry about it accidentally opening, and the earbuds are held in their charging sockets by a similarly powerful set of magnets; I had no problem removing and replacing them.

The outer surfaces of the earbuds are touch-sensitive, and A&K has also integrated wear sensors on their inward-facing sides.

Audiophile internals

A close-up of the Astell&Kern AK UW100 arbuds without eartips.Simon Cohen / Digital Trends

Inside the UW100, A&K has gone to a lot of trouble to make sure these earbuds live up to the lofty expectations of the audiophile community. It has used single Knowles balanced armature drivers instead of the far more common dynamic driver. Those drivers are powered by an Asahi Kasei AKM AK4332 32-bit Hi-Fi combo amp/DAC that A&K says is similar to the circuitry it uses in its portable media players.

Most wireless earbud companies don’t talk about the specifics of their DACs or amps because the average buyer doesn’t know or care about these components as long as everything just works. But A&K customers aren’t average buyers and they do care, so the company is making sure they know that the UW100 aren’t just a collection of off-the-shelf parts with an A&K logo stamped on them.

Comfort, controls, and connections

A close-up of Astell&Kern AK UW100 accessories including a USB-C charging cable and five sizes of silicone eartips.Simon Cohen / Digital Trends

Big earbuds are, as a rule, less comfortable than smaller ones. And while it’s true that the UW100 are less comfortable than the AirPods Pro or Jabra Elite 7 Pro, they’re just fine for a few hours at a time. They’re also surprisingly secure-fitting. I used the UW100 at the gym and they didn’t budge, but their lack of an official IPX rating did make me think twice before cleaning them.

The touch control surfaces are easy to use despite the unusual shape created by their multifaceted design.

It shouldn’t be hard to find the right eartip size for your ears; A&K includes a generous five sizes to pick from. When you pluck the earbuds from their case for the first time, you’ll notice that there are no eartips installed. That’s by design.

Too often, people stick with whatever comes installed from the factory, only to later complain about a bad fit, or worse, bad sound. Both problems can be solved by using a different size of eartips, and by requiring that you install a set of tips before you can use the UW100, A&K gets you to actively think about these choices.

The touch control surfaces are easy to use despite the unusual shape created by their multifaceted design, and a short tone lets you know when you’ve tapped successfully. Of course, it’s the same single tone whether you tap once, twice, thrice, or long-press, which is somewhat counterintuitive.

Of those four gestures, the AK TWS app lets you customize the double- and triple-taps, but your choices are extremely limited: On each earbud you can choose between track skipping, voice assistant access, and ambient mode level. All of the other commands (play/pause, volume up/down, call answer/end, and ambient mode on/off) are hard-coded to specific gestures and earbuds. If you need to mute the mic during a call, you’ll need to use your phone’s interface. Still, it’s a comprehensive list of features.

The wear sensors do a good job of auto-pausing and resuming music playback when you remove or replace an earbud, but there’s no way to defeat this feature in the app, or modify how it works. A&K should consider adding this in a future update.

This kind of performance lends itself to virtually any music genre.

The UW100 use a Bluetooth 5.2 connection, and pairing is quick and easy. They also support Bluetooth multipoint for two simultaneous device connections, which is still a rarity in the wireless earbud world — kudos to A&K for doing what Sony, Bose, and Sennheiser have still failed to implement. Wireless range is standard for a Class 2 product: About 30 feet, but that will vary with the phone you’re using and what kinds of obstacles are around.

For the most part, the connection was strong and reliable, with the exception of one morning as I walked to the gym and both earbuds intermittently dropped out for 2 seconds before reconnecting. This only lasted for about 10 minutes and it didn’t recur, so I can’t say what was going on, but it’s possible that A&K will need to issue a firmware update if the problem persists.

Sound quality

A man wears the Astell&Kern AK UW100 earbuds.Simon Cohen / Digital Trends

The UW100 sound fantastic, and easily rival Master & Dynamic’s MW08, Sony’s WF-1000XM4, KEF’s MU3, or the Grado GT220 in all of the areas that matter. Like all great headphones, there’s ample separation between frequencies. The bass never stomps on the midranges, and the highs ring through with crystal clarity.

Knowles balanced armature drivers

A&K’s decision to use single balanced armature drivers from Knowles, instead of a more traditional dynamic driver, has paid off. In the past, I was under the impression that you needed multiple balanced armature drivers, each tuned to its own specific group of frequencies, in order to compete with a top-quality dynamic driver. But the UW100 have convinced me otherwise — at least as far as wireless earbuds are concerned.

A close-up of the Astell&Kern AK UW100 earbuds with silicone eartips installed.Simon Cohen / Digital Trends

Their bass response is fast and precise, never muddy, and the midrange detail will get you to stop what you’re doing, sit down, close your eyes, and just listen to your favorite tracks. Billy Idol’s Bitter Taste, a track that I can barely listen to on some earbuds because of their tendency to increase sibilance, was smooth as silk. Bubbles by Yosi Horikawa is a fantastic song for soundstage precision and the UW100 had me wanting to reach out and grab the bouncing marbles that lead the intro. And Billie Eilish’s Bad Guy — a torture test that layers Eilish’s whispering vocals over a massive bass line — sounded as good as I’ve ever heard it.

This kind of performance lends itself to virtually any music genre. Unless your sonic preferences lean heavily toward ultrapowerful bass, you’ll love the UW100’s default tuning.

Codec confusion

The UW100 uses Qualcomm’s QCC5141 chipset, which includes support for the aptX Adaptive family of Bluetooth codecs. In theory, aptX Adaptive should automatically use the best codec supported by both your source device (likely a smartphone) and your earbuds. In my case, this is aptX HD, a 24-bit codec. But for some reason, on both my Google Pixel 5 and my A&K SR25 media player (both of which support aptX HD), I could only get regular 16-bit aptX to work.

As useful as these EQ presets are, they’ve simply whetted my appetite for a full-blown manual EQ option.

In checking with A&K, it seems this is a known bug that’s being worked on. Without hearing it for myself, it’s hard to say just how much better the UW100 will sound when using Qualcomm’s 24-bit codec, but given just how good these earbuds sound when using AAC or aptX, any further improvement will just be the cherry on top.

Aspirational EQ

Top view of Astell&Kern AK UW100 sitting in their charging case.

Astell&Kern AK UW100

A&K could probably have taken the same route as Master & Dynamic, KEF, and Grado, and let the UW100’s out-of-the box EQ speak for itself, but it chose to include four presets in the AK TWS app, including bass emphasis, high emphasis, vocal emphasis, and game mode. The first three work exactly as you might expect, and game mode attempts to create a slightly more immersive environment by emphasizing key in-game sounds like footsteps, while simultaneously deemphasizing lower frequencies that might interfere with your situational awareness.

I’ve gotten much better calling results from much cheaper wireless earbuds like the $80 Jabra Elite 3.

As useful as these presets are, they’ve simply whetted my appetite for a full-blown manual EQ option, which isn’t available right now. Flipping back and forth between bass and vocal emphasis modes is enough to illustrate how much tuning potential exists in the UW100, and I want the ability to create my own EQ recipes instead of relying on A&K’s prix fixe menu.

I mentioned this desire to A&K’s spokesperson and was told that the company might add it as a feature in a future firmware update, but for now there was no plan to do so.

Ambient mode

A screenshot of a phone displaying the Astell&Kern AK TWS app.A&K includes an adjustable, four-level transparency mode (which A&K calls ambient mode) that you can flip on and off with a single tap on the left earbud, and it works during music playback, too. At levels one through three, you get progressively more access to the outside world. Once you get to level four, the built-in mics start to aggressively amplify those external sounds, which could be handy in noisy environments like restaurants.

It does a good job with other people’s voices, but it can’t quite make your own voice sound natural, as opposed to the AirPod Pro, Bose QuietComfort Earbuds, and Sony’s WF-1000XM4, each of which does a better job at making transparency feel like you aren’t wearing earbuds at all.

Another drawback is that every time you switch ambient on or off, a voice comes on to announce the change. It’s distracting, especially if the reason you need ambient mode on is to hear something important like an announcement in an airport, and there’s no way to disable it.

Call quality

Unfortunately, A&K has some work left to do to bring the UW100 up to par with its competitors when it comes to phone calls and other voice applications. Ambient mode is incompatible with voice calling, so you can’t hear an unmuffled version of your own voice. But the bigger problem is the quality of the voice pickup. During an outdoor recording session, I found a lot of compression and distortion crept in, and at times my voice sounded distant — like I was a few feet from the mics, not mere inches. I’ve gotten much better results from much cheaper wireless earbuds like the $80 Jabra Elite 3.

With two mics per earbud — the same as most products at this price — I suspect the problem stems from the background noise cancellation settings that A&K has used. When these algorithms are overly aggressive, they can adversely affect voice quality as they attempt to neutralize other sounds.

Subpar call quality isn’t ideal at the best of times, but it’s especially disappointing considering the UW100’s Bluetooth multipoint capability, which is perfectly suited for folks who want to quickly switch devices to place or receive their calls or meetings.

Battery life

Back view of the Astell&Kern AK UW100 charging case.Simon Cohen / Digital Trends

A&K claims you’ll get six hours of playing time per charge from the UW100 earbuds, and a total of 24 hours when you include the charging case’s capacity. During my testing, those numbers seemed accurate, as long I stuck to a 50% volume level. A ten-minute quick charge will get you an extra hour’s worth of use.

That’s about the same as the AirPods Pro, but considerably less than the Master & Dynamic MW08, which can muster up to 12 hours per charge when not using active noise canceling, and up to 42 hours of total time.

What’s missing?

As you’ve likely noted already, the UW100 don’t have ANC. But they could. The Qualcomm QCC5141 chipset supports it, and A&K could opt to enable it via a firmware update. Why isn’t it turned on by default? The company says it just wasn’t happy with how the earbuds performed when ANC was in use.

“The UW100 uses an audiophile-grade DAC for sound quality,” a spokesperson told Digital Trends. “There was a noticeable drop in sound quality from the DAC when using ANC, so it was decided to not implement ANC to prevent degraded sound quality.” I suppose that’s reasonable, especially when you consider how good the passive noise isolation is.

Our take

With sound quality that rivals the best wireless earbuds we’ve ever tested, the A&K UW100 are a joy to use. But at this price, I think buyers should be able to expect great call quality, solid protection from water, and active noise cancellation, too.

Is there a better alternative?

For sound quality, no, I don’t think you’ll find a set of earbuds that outperform the A&K UW100 — they’re that good. But as important as sound quality is, it’s not everything. For the same price, you can buy the Master & Dynamic MW08. They have a longer battery life, better call quality, and ANC. On the other hand, they don’t do Bluetooth multipoint and they lack wireless charging, which only comes with a $50 upgrade to the MW08S.

For a few dollars less, Sony’s $280 WF-1000XM4 are jam-packed with features (except Bluetooth multipoint) and their equalizer lets you tweak their sound any way you want. I prefer the sound of the UW100, but the Sonys are still superb.

How long will they last?

The UW100 seem solidly built, but without an IPX rating it’s hard to say how they’ll hold up to water and sweat. As with all wireless earbuds, the big question is how many years will you get before their battery capacity drops to the point where they become unusable — and that will depend on how often you charge them.

Should you buy them?

Yes. A&K has pitched the UW100 as an audiophile’s wireless earbuds and they most certainly deliver on that promise. As long as you don’t mind their flaws (mediocre calling, no ANC), you’ll be treated to an impressive sonic performance.

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