KEF Mu3 Noise Cancelling True Wireless Earphones Review

Posted on 14th October, 2021

KEF Mu3 Noise Cancelling True Wireless Earphones Review

With an exceptional loudspeaker pedigree behind it, how does the first noise-cancelling earbud from KEF shape up, asks Matthew Jens?


Mu3 Noise Cancelling True Wireless Earphones

USD $249 (~S$332) RRP

Well, this is interesting. No, I'm not talking about the fact that KEF is dipping its toes into the True Wireless earbud market. Practically every brand under the sun is doing that by now. The exciting part is that KEF dragged Ross Lovegrove back into the ring to design this new release. Yes, that Ross Lovegrove, who helped not only develop the Sony Walkman back in the day but is also responsible for the kilobuck Muon loudspeaker icons. 

KEF has a strong pedigree in audio quality and acoustics, dating back to 1961. Not to mention the ridiculously successful LS50 series, which has dominated the small home speaker market for quite some time. We have all the right ingredients for this new release – tried and tested star industrial designer, a half-century-long speaker design pedigree, and the technological leaps of headphone development in recent years. So let's see what happens when these are all mixed together, with the garnish of a premium price tag…


Bulky, these are not. At only 5.8 grams, the Mu3s are a very welcome change to the hefty alternatives on offer, such as the Bowers & Wilkins Pi7 and the Devialet Gemini. The former being 7 grams, and the latter being 8 grams, both of which are considerably chunkier than the Mu3. For reference, they're similar in size to the AirPods Pro; and almost identical in weight. However, the substantial physical benefit here is that the KEF design is IPX5 splash-proof, compared to the AirPods Pro, which is IPX4. 

These are, by true wireless standards, tiny. Not only that, the intricate contoured design means they fit exceptionally well into the ear. These, without fail, are some of the most comfortable true wireless releases I've worn to date. They are made of plastic, and the design echoes back to the other forms of curved industrial engineering work by Ross Lovegrove. The Muon is a perfect example of this language, with not a straight line to be seen anywhere.

The case speaks to this, too, with its soft dimpled lid and forever rounded edges. Functionally though, it has powerful-as-all-hell magnets that stick the Mu3 in place. Handy because you can lazily toss these earbuds back into their case, and the magnets will reach out from miles away and drag them perfectly back into their charging cradle! Thankfully, the case also features USB-C and is small enough to fit into a pocket or bag.

The plastic build of the buds and case make me worry about longevity. Not only am I concerned about how easily scratched they might get, but I also feel like I'll break them immediately if I sit on them. As a result, I've been babying this pair like nothing else. They are, after all, quite pretty – albeit dainty. 

Battery life is rated at 9 hours, with another 15 hours ready to go in the case. Juicing up the Mu3 for only five minutes will give you one hour of use with fast-charging capability. I'm not a betting man, but being unable to test these claims thoroughly, I am willing to put money on them being generally correct. I only had to charge the Mu3 once through my entire testing period with them.

The whopping 8.2mm drivers are sadly only fed by SBC and AAC codecs. Generally, I consider these codecs adequate but considering the vast array of connectivity options offered by the KEF LS50 wireless, I'd have liked some expanded connection functionality here – perhaps along the lines of aptX or LDAC support. Thankfully, this department is salvaged by the use of Bluetooth 5.0.

Being as small and light as the AirPods Pro, these are already off to a good start in the comfort race. Instead of hanging out of the ears, they curve upwards, closely following the shape of the inner ear. It's a unique approach to fit, but one that's paid off. I can easily go running or boxing in these, without fear of them flying out. The ultimate comfort litmus test for me is my partner, who has tiny ears and is extremely fussy with earbuds. Most of the units I bring in for review are not suitable for her ears, but the AirPods Pro are light and small enough to be a perfect fit. Interestingly, this KEF design also fitted these criteria and are wife-friendly in my context. 

Usually, at this point in the review, I would talk about the customisations available in the included app, such as EQ, adjusting the settings, or maybe adjusting the noise cancelling. But no, we won't be doing any of that – there's no included app at all with the Mu3, so what you hear is what you get. Thanks to the simplicity of the single button controls, the app omission could be considered tolerable. However, a tech nerd inside me is worried about obsolescence and security. No included app also means no chance of a future firmware update, ever!

Each earbud can be listened to independently in more positive news, which is quite a rare feature in this market. KEF has gone one step beyond this and has a neat feature that downmixes all content into mono when listening, so if you want to lay down and listen to only one ear, you can do so without missing out on anything. Very cool.

These earbuds also have a lightning-fast reconnection once paired. As soon as you get them out of the case, boom, they see your phone. You can basically “hot swap” either bud back into the case, and the other will immediately switch to mono mode. Very convenient. 


Armed with my trusty Galaxy Z Fold 3, I put the KEF Mu3 to work. The first cab off the rank was the aggressive but quirky stylings of Goonies Never Die by Immortal Technique. The song is a good test of how cohesive an IEM can be, as the complex orchestral elements can become muddied by the overbearing vocals. The KEFs did an adequate job of piecing this piece together and remained composed and controlled the entire time. Even the louder vocal accompaniment didn't overshadow the rest of the mix too much, which came across as inoffensive, with no painful sibilance or ringing. 

The sound signature here harks back to the neutral, accurate reproduction of the LS50 series. Indeed, considering this for a moment, the KEF KC62 subwoofer was a welcome pairing to give them some help down low. As the Mu3 echoes similarities with the LS50 in some respects, it too would benefit from some of this boosting down low.

This softer bass impact does help these IEMs lean into KEF's claim of having “pure, accurate sound… anywhere”. When I listened to Once You by Jacob Collier, these sound descriptions used by KEF rang true. The string instruments came through with vivid detail and sounded as accurately as they do on my over-ear Sennheiser HD560S. Jacob was quite an enjoyable listen on the Mu3, not just due to the neutrality and accuracy portrayed by the dynamic drivers but also because of the unfatiguing sound that allowed me to take the whole track in. Dynamic range proved impressive too, which came to the forefront once the vocals kicked in.

The Mu3 are an engaging, intimate listening experience with plenty of dynamic range and detail. Once the violin started seeping through at the 5:23 mark, it was hard not to take notice of the impressive soundstage thrown out by these little things. Driver matching between the two sounds is spot on, and the sense of imaging is superb. The noise-cancelling falls short of being effective, however, and the ambient mode is only marginally better. Toggling between these settings renders only minor differences in sound, and I would often forget which setting was currently toggled on – except for some extra noise being let in on ambient mode.

Thankfully, call quality is good. People on the other end of the line commented that I sounded just fine and had no connection issues whatsoever. I know I say this a lot, but it's an important thing to highlight – not many true wireless earbuds get call quality right, so the fact that the KEF offering nails it deserves to be treasured. 


KEF has put together its best ingredients for the Mu3, and the result is a beautiful, neutral, natural listening experience, class-leading ergonomic fit, and spectacular battery life. Yet, the technically minded may feel inclined to look elsewhere, as the ANC isn't the best, and there's no included app to change the settings or tweak the sound. So with all of these ingredients, I'm happy with this first entrée whilst looking forward to some developments that will see a perfect main course come next.

For more information visit KEF

    Matthew Jens's avatar

    Matthew Jens

    Constantly keeping himself busy, Matthew is a production manager, Brazilian jiu-jitsu blue belt, Head-Fi fanatic, coffee enthusiast and all-round cool Dad.

    Posted in:Headphones Noise Cancelling True Wireless Bluetooth / Wireless
    Tags: kef  atlas sound & vision 


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