KEF Mu3 True Wireless Earbuds Review: Beauty And The Beat
"Despite the mediocre ANC, their slim design and great sound make for an appealing package."
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Beautiful design
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Comfortable fit
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Fantastic sound
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Very good battery life
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IPX5 water resistance
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No app for EQ or control tweaks
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No wireless charging
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Mediocre ANC and transparency
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Mediocre call quality
KEF is one of the best-known names in hi-fi, thanks to speakers who have impressed reviewers and enthusiasts for years. The company's LS50 wireless bookshelf speakers are a great example of what happens when you combine classic acoustic expertise with cutting edge technology. I was excited to receive the company's first true wireless earbuds, the $ 230 KEF Mu3. Given the stiff competition from Sony, Bose, Jabra, Sennheiser and Grado, has KEF brought enough of its world-class audio technology to the Mu3? Let's take a look …
What's in the box?
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In KEF's all-cardboard and easily recyclable box, you'll find the Mu3 in the charging case, a USB-C charging cable, three additional sizes of silicone earbuds (plus the standard media installed on the earbuds), and quick start documentation.
design
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Let's get one thing straight right away: The KEF Mu3 are stunningly beautiful. Both the earphones and the charging case look like sculptures made of highly polished aluminum. They are smooth and shiny. If you leave the charging case in a prominent place like a coffee table, desk, or kitchen counter, people are guaranteed to find themselves unable to resist picking it up just to feel it.
For those who like to get lost in the details of their favorite songs, the Mu3s are more than happy to do so.
The attention to detail continues right through to the hinge mechanism. Most charging cases have weak lids that could break if you aren't careful. If their magnets don't keep them in the closed position, they flutter about worryingly. The lid of the Mu3 feels luxurious by comparison, with a hinge that reminds me of a laptop screen – it stays in any position from open to fully closed. With its aluminum look, it's basically the MacBook Air for charging cases.
Unfortunately, the case is also a bit bulky, so despite its sensual curves, it's not very insertable. But that's fine – KEF seems to have used a hard transparent outer layer on the plastic, and I think it will withstand scratches caused by other objects.
These earbuds also have very acceptable IPX5 water resistance that should protect them from anything other than actual submersion in water.
Comfort and control
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The KEF Mu3 comes with four sizes of soft silicone ear tips, which should mean most people can get a good seal. And here is some valuable advice on the matter: If you feel the need to plug the earbud deep into your ears (which is possible due to its small size), you are probably using the wrong size earbuds.
They did not move at all and felt very comfortable even after several hours of continuous use.
Pushing them in too deep not only becomes uncomfortable, but also degrades the sound quality and the effectiveness of the noise cancellation. I discovered that the hard way. I also found that with the largest earbud I could insert the Mu3 carefully and they didn't move at all and were very comfortable even after several hours of continuous use.
KEF used physical buttons on the Mu3, and that's definitely a good thing. Touch controls can be tricky at best, and I prefer real buttons when they are available.
These buttons are easy to press, but strangely enough, the right button had a more pronounced click response than the left.
With a combination of single, double and long press you can control everything except to jump back a track. However, there is no way to customize these gestures through a smartphone app as KEF didn't create one for the Mu3.
There are also no wear sensors. So if you pull out an earbud, your tunes won't automatically pause.
Sound quality
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The KEF Mu3 are wonderful to hear. Their bright and clean highs, precise mid-tones, and expertly executed bass create surprises with every new track you start. There's no trace of mud that often obstructs smaller earbuds. Applying instrumental jazz standards like Dave Brubeck's Summertime or Duke Ellington's St. Louis Blues, you can appreciate the sheer musicality of KEF's mood, not to mention the soundstage, which is so tightly controlled it feels like the distance between instruments up to being able to measure the inches.
For those who like to get lost in the details of their favorite songs, the Mu3s are more than happy to do so.
When I played it for the first time, I was disappointed with the bass and feared that KEF had become too conservative with the low end in an effort to achieve this so-called “neutral” or balanced EQ. It turned out that I just wedged the earbuds too far in my ears.
When I found out my mistake, I found that not only is there a lot of bass on tap, but that the Mu3s can also use that bass selectively and only hit you with deep resonance when needed.
The transparency mode (ambient sound mode) doesn't let in as much noise as I want.
I think the Mu3 are near perfect in terms of EQ, but since listening experiences are the subjective things they are, you should know that the lack of an app means there is no way to rebalance the sound signature, if it doesn't suit your needs.
Noise cancellation and transparency
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Active Noise Cancellation (ANC) has become a standard feature of true high-end wireless earbuds, but there is still a huge difference in how each model performs. The Mu3 noticeably reduces the low frequency noise when the ANC is activated. However, it's a far cry from the silence offered by the Apple AirPods Pro, Bose QuietComfort Ear Buds, and Nuheara IQbuds2 Max.
Similarly, the transparency mode (ambient sound mode) doesn't let in as much sound as I would like. It certainly makes conversations easier and gives you greater situational awareness, but it's not the magical "hey, it's like I'm not wearing earbuds" that these other models convey.
Without an app there is no way to dial in one of the two functions and not to change the ANC trigger action. A single press of the left earbud controls noise cancellation, but forces you to toggle between three modes (ANC, Off, and Transparency) instead of being able to toggle between ANC and Transparency, which are actually the two most commonly used modes.
Battery life
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KEF really surprised me here. Most true wireless earbuds – even the very expensive ones – typically have a battery life of five to seven hours on a single charge. But the Mu3 delivers nine hours – and that with the ANC switched on. This is by no means the longest time, but it doesn't have to be. After another 15 hours in the charging case, you have a whole day before you have to connect the USB-C charging cable.
Better still, they also have a five minute quick charge system that gives you an extra hour of playtime. My only real disappointment is the lack of wireless charging. When KEF first announced the Mu3, wireless charging was one of the features listed so it may be available again in a future version.
Call quality
I've found a strong correlation between an earbud's ANC / transparency performance and its call quality, and the Mu3s are no exception. You do a little effort not to lose your voice in front of competing background noise, and the sound that is recorded has a scratchy, thin quality to it.
They're probably much better indoors, but outdoors, where a lot of calls seem to be making through earbuds, the Mu3 should be used sparingly.
Our opinion
Although they lack some of the features we would expect from true wireless earbuds at this price point, the KEF Mu3s are beautifully finished, sound amazing, and have a generous battery life.
Is there a better alternative?
As good as the Mu3 is, you will find more features with comparable sound quality and prices in these competitors:
The $ 230 Sony WF-1000XM3 App-supported EQ, adjustable ANC and transparency, longer battery life, better call quality, support for Google Assistant and Amazon Alexa and customizable controls
The $ 230 Jabra Elite 85t App-assisted EQ, wireless charging, adjustable ANC and transparency, customizable controls, a feature to find my earbuds, and better call quality, but they don't sound quite as crystal clear as the Mu3.
The $ 230 Grado GT220 sound very similar to the Mu3 and charge wirelessly, but they don't have ANC or transparency mode and are considerably bulkier.
How long will they last?
The KEF Mu3 appears to be very well built with high quality materials. KEF gives them a two-year guarantee, which is better than many of its competitors. When you add their IPX5 rating, I think they will last for many years if properly cared for.
Should you buy it?
Yes. The Mu3 ignores a lot of the bells and whistles and instead focuses on a beautiful design, a comfortable fit, great sound, and great battery life. As long as you agree to this compromise, they will provide a great listening experience.
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