Review: KEF Mu3

Earplugs that please the eyes

KEF's first wireless earplugs are not perfect, but they do one thing better than other earplugs.

Published 2021-05-17 - 8:50 am
Lasse Svendsen

They look undeniably good. In fact, the designer, Ross Lovegrove has even put his signature on the case, and it is the same man who designed the wildly popular KEF Muon, and the portable Bluetooth speaker Muo, at a fraction of the price.

But Lovegrove has had nothing to do with the sound, it is unmistakably KEF. Large, rich sound with a warm sound in an open and detailed sound image. Just as one would expect from a pair of LSX or Blade speakers.

The small earplugs follow the same pure design language used on Muon – and Muo, with organically shaped curves and not a single hard angle or sharp edge. In this respect, they are clearly different from the Bowers & Wilkins PI7, and the reference Sony WF-1000XM3.

Nice design by Ross Lovegrove, who also designed the KEF speaker in the background. Photo: Lasse Svendsen

Mu3 has active noise reduction, Bluetooh 5.0, and are only available in titanium gray. The same design is used on the case. Which extends the battery life by another 15 hours, from the nine that the plugs have from fully charged status. The case is a bit bulky, but nowhere near as big as the case of the Sony plugs, not to mention the case of the Beats Powerbeats Pro.

The case is charged with cable, and does not support wireless charging, and if you are running out of power just before boarding, it is nice to know that five minutes of charging gives one hour of playing time.

The earplugs are also splashproof, with IPX5 certification, and with silicone earplugs in the right size (four sizes are included), they fit well in the ears. Also when taking a jog.

Ease of use

Once the KEF plugs have been placed in the ear, they are easily paired with the mobile phone. Who recognizes them every time you take them out of the case and place them in your ear. KEF does not offer app control of the plugs, as they do on Muo, and therefore there are no adjustments to the eq or the active noise reduction.

Which, having said that, works well enough to make one notice well that noise from outside is muted. Well. But not quite as good as on the Sony plugs, which are better at adapting the attenuation to different frequencies. Deep frequencies are better attenuated on the WF-1000XM3, but are preserved, if you press the ambient button on the left earplug, you immediately hear how much noise is actually outside the earplugs. The call quality can best be described as ok, these are not the ones you should use in the home office, but it is perfectly fine to conduct a call every now and then.

We like physical buttons better than touch surfaces on earplugs. Photo: Lasse Svendsen

Fortunately, there are no touch interfaces here.

Everything is operated with physical buttons. The one on the left alternates as mentioned between ambient and noise reduction, but also volume down when you hold the button in, while the right one increases the volume when you do the same there. It is also the button on the right you use when you start and stop the music, skip songs with two quick taps, or answer an incoming call.

The range is very good indoors as well. You can leave your mobile phone lying around while walking around the house, and in my brick house it was no problem to move between the floors without the music dropping out or stopping.

The case provides an additional 15 hours of battery life. Photo: Lasse Svendsen

Sound quality

Many of the wireless earbuds we have tested sound a bit sharp and although they may have plenty of bass, it is often thin in the midrange. It can give a sound image that is not so pleasant over time. You quickly get tired of excessive bass and ongoing treble, but the KEF plugs have none of the parts. Preserved, they have plenty of bass, but it is primarily full-bodied, while the treble is – a little much – better muted so that the sound is far more pleasant.

But it is the midrange that perhaps surprises us the most. It is open with good detail, and delivers the music with warmth and depth of sound. Robin Thicke’s Take Me Higher really fluctuates when you turn up the volume. The bass passage during the rhythmic clapping is well defined, and the blow of the windshield never sounds sharp or uncomfortable.

On this spring’s big hit, Leave The Door Open, with Bruno Mars, Anderson Paak and Silk Sonic, the vocal harmonies could have been better defined, but then there are not a few Airpods Max we are talking about either.

It can not be charged wirelessly, but is compact and easy to put in your pocket. Photo: Lasse Svendsen

If you change genre and put on Moon And Sand with Keith Jarrett Trio, you notice how well defined the double bass of Gary Peacock sounds through the KEF plugs, but I miss a little more attack and depth in the piano. Anne Sofie von Otter’s crystal clear soprano, on Verdi’s Reqiuem, can make a granite heart burst, and do the next thing here as well. For the KEF plugs, vocals provide a natural-sounding warmth that so few other wireless earplugs can handle. Bravo.


The strength of the small and very gorgeous KEF Mu3, is certainly the warm and full sound that suits a wide range of music. At the same time, they are wonderfully comfortable to listen to, for a long time, they sit well in the ears, and they look damn good. The noise reduction is good, but not the best and could have been more effective, and it is conceivable that there are more than us who miss than the app with eq settings. But there are still a couple of the best earplugs out there in terms of sound.


We think

Super comfortable sound image with bold bass and warm sound. Very good battery life. Splash-proof and trustworthy quality. The active noise reduction is not as effective as on our reference. A little too ladi back treble.
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