Astell & Kern AK UW100MKII Review
It has been a few minutes since I wandered into the market of True Wireless IEMs. Admittedly, the ever expanding sector is still dominated by Apple’s two Airpod variations, which is now in their 3rd generation for the buds and 2nd for the in-ear “pro” option. The subject of today’s review falls in with the second category more than the first, as Astell and Kern’s AK UW100MKII embed themselves into the ear canal in a very similar fashion, and also include several swappable eartips to ensure a good fit.
It does seem necessary to include that last bit of information in every earphone review, as a improperly sealed in-ear can ruin a reviewer’s day. Bass can lose its impact, and even mids and highs can get a little funky without the proper adjustment for everyone’s unique ear cavity. The good news in the case of the AK UW100MKII is that the contour and size of the body of the unit fit very comfortably into my ear and didn’t seem to weigh down or pull on the tip too excessively. While I might not take them out for a sprint or a trampoline park, walking and running kept them in place without any extra effort. Likewise connecting them with my iPhone was free of any major issues as well. A simple setup through the Bluetooth menu and we were on our way. Like Apple’s easy Airpod connection (all that is need is to open the case next to the phone) the AK UW100MKII carry a similar feature for phones of the Android persuasion called Google Fast Pair. I wasn’t able to test this option out, for lack of a google device, but I’m assuming it is as nice to have as Apple’s variation is. A pleasant thing to experience if you don’t want to dig through two menus to connect your device, as simple as that already was.
The latest gear is strapped with the latest tech, at least that is hope for most cutting edge adopters and the AK UW100MKII does not disappoint on many fronts. Pairing Bluetooth can be done with quite a diverse application. Not only can you pair with multiple devices, but with up to two points can playback at once – according to the company website you “can also listen to songs played on your tablet PC while actively allowing phone notifications and calls from your smartphone”. That may be pretty basic bread and butter for Bluetooth these days, but where the tech starts to get a little more impressive is the silicone under the hood. Offering a 32 bit internal DAC may seem like overkill for an iPhone connection that sends much less than that over Bluetooth (v5.2 max, in the case of the 100MKII) but there are two other important design features that stand out to note here.
First, there is an emphasis on PNI or Passive Noise Isolation. While this three letter acronym ultimately means nothing more than the same effect if you plugged your ears with your fingers, its contrast to the ANC (active noise cancellation) efforts in the market are quite significant. Despite what the marking jargon might tell you, most ANC does seem to effect sound quality in an adverse way, and given its absence here with all the other bells and whistles, seems to be a downright line in the sand on the topic. And the solution to the highest SQ might just come in the form of refining the earplug after all, as AK appears to put some design effort into increasing these natural attributes of the in-ear category. Stage performers are no stranger to the concept with the overlapping custom IEM market, why can’t resellable universal fit options borrow some of those same positive characteristics? AK posts some of its tests on their site showing increased levels of noise reduction due to the physical design of the unit. And truth be told, much of my personal experience with ANC shows that while it works well for airplane noise, perhaps other applications just aren’t quite their yet, at least in the consumer market of headphones.
Adjacent to that, we have 4 levels of ambient listening mode on tap. This mode allows outside noise to come in, in case your boss just walked up behind you and wants to interrupt your latest listening sesh. This feature isn’t new, but it is nice to have, especially if AK is touting more and more PNI, some matter of safety options should be considered for more athletic applications as well. In use, the noise reduction felt pretty standard with silicone tips, perhaps foam options will allow for even more protection. The ambient feature works okay as well, but the PNI wasn’t quite to the levels that I couldn’t make out voices by just shutting off the music.
The driver design incorporates a single Knowles-branded balanced armature driver. While some higher-end IEMs may tout large arrays of 16 or more BAs, I find that if implemented properly a single driver will do just fine in physically tight situations, like we find ourselves in the TWS category with all the extra digital contingencies that are needed.
Perhaps the second biggest tech jump in category is the claimed battery life however. Early models of TWS earphones barely made out with 5 hours of playback before they needed to be housed in a supplement case. Not a huge deal for most applications, but the AK UW100MKII touts almost double the listening range (9.5 hours) so any advancement there is a welcome option to have – should the need arise. Including some case charging, AK estimates 29 hours of total playback.
According to the gauge on my recharging station, the AK UW100MKII did pull a full 2W of juice during its fairly quick chargeup through USB-C. That is a full 1W more than my Airpods usually draw, so some new specs on the front are welcome as well.
The AK UW100MKII also claims some pretty fancy updates to the internal delivery service for the BA driver. An additional “acoustic chamber” is incorporated into the sound path. Some manufacturers have seen success with designs like this in my experience. Campfire Audio’s Andromeda series was one of the first that we reviewed with a sonic chamber and its tonal structure felt just a tick more realistic than the rest of the group at that time. Do executions like this simply add more pleasurable distortion like analog tubes do in amplifiers? Maybe, but ultimately if designers are listening to the output and making the proper adjustments, more strides can be made to get the in-ear listening experience closer to real life, outside of Apple’s efforts with Spatial Audio. I tend not to use Spatial Audio tracks while reviewing gear. While I do enjoy the surround effect, the tracks I have heard appear to have an augmented EQ from my usual reference songs, and that really throws things off from a comparison standpoint.
The number one takeaway from the AK UW100MKII listening experience is best summed up in one word: resolution. The detail and ultimate fidelity of the playback is one of the best I’ve ever heard from a True Wireless earphone. The resolving power of the design really lets the listener peer into the music. Sounds from the far left and right push out slightly, and dimensionally is increased over flatter, softer sonic stages that are constructed from most options that pepper the market. The highs and mids were particularly articulate. The out-of-the-box settings were a touch light on the bass for my preferences, but the AK mobile app allows for adjustments to the frequency curve. And with this type of customization available, it puts even more weight on the perceived resolution than ever before. If you have a solid baseline to work off of, then individual EQ preferences become less of concern to the generic build of any response. I use the work “perceived resolution” specifically in this context. The wireless connection is still lossy from my iPhone, even though the AK UW100MKII does option the apt -X Adaptive codex in front of the internal 32-bit DAC.
The two biggest drawback of the earphone is probably the touch interface and the overall build of the case. The touch interfaces is a bit…touchy. While this is by no means unique to the AK UW100MKII (I’ve come across far too many hard-to-use touch surfaces in the TWS market) a ultra responsive surface would just have been more consistent with the rest of the steller features of the earphone. To get the touch capabilities to work, one needs to touch the earphone only on the conical tip of the design, and nowhere else. The touch needs to be done with an exact pressure as well, which takes some getting used to. With proper training, a useful interaction can be had, but I found this hurdle to be under par for the rest of the exceedingly impressive feature set as a whole. However, outside of a few athletic implications, I typically just control things from my phone, so the issue is neither here nor there for most of my daily listening routines.
The second small quibble is the construct of the earphone case itself. The upper lid feels a bit plastic-y and thin for my tastes. My DJI microphone case offers some of the same use-case, and is coated in a more rubber-like texture. While the internal portion of the lid does sport nearly an identical feel and texture, a slightly thicker build on the AK UW100MKII case might serve up a heightened sense of luxury.
The AK UW100MKII is a resolution beast in the True Wireless category. The credit might be due to new specs in Bluetooth, the internal 32-bit DAC or even the Acoustic Chamber, but regardless, it helps usher in a new wave of perceived tonality that has been severely lacking since technology decided to give up on wired options in the mobile sector. This is some of the core benefit the product offers up, and likely the driving reason someone naturally considers sound-quality focused brands like Astell And Kern. There are a ton of options out there, but few put priorities to the same thinking points as audiophiles do. Seeing a new product executed in this manner is quite the refreshing breath of fresh air… in a slightly stagnating supply of consumer-oriented phone accessories. Well done.
More info: Astell and Kern AK UW100MKII