Review: Sony WF-1000XM4

Sony's best so far

Sony has shrunk its top model a lot. The WF-1000XM4 is a pair of really good earbuds. If you adjust them correctly.

Published 2021-06-08 - 6:00 pm
Sony WF-1000XM4
Geir Nordby

When Sony launched their best wireless earbuds so far in 2019, namely the WF-1000XM3, we were impressed with how seriously they had taken the job. Exquisite noise reduction, magnificent bass and a – by the standards of the time – very stable connection.

It has now been two years, and one by one the competitors have caught up with the Sony ones. First of all, the Sony did not have any form of waterproof certification, the Bluetooth connection could give some tiny dropouts in the form of gentle crackling sounds, and they were also quite large and bulky.

Sony WF-1000XM4 box
The new earplugs come in more environmentally friendly packaging than before. Photo: Sony

Now the successor is here, with the predictable name WF-1000XM4, and Sony has not rested on its laurels here. With improved noise cancellation, hear-through, and finally waterproof with IPX4 certification. Battery life is also better, 8 hours from the plugs themselves with noise cancellation activated, and two extra charges from the case. With fast charging, you also get over an hour of playing time after 10 minutes of charging.

Sony WF-1000XM4 Lifestyle(7)
The Sony WF-1000XM4 can charge wirelessly, but you must get yourself a Qi charger. Photo: Sony


The earplugs have shrunk since the last time, the housing take up 10 percent less space than before, at the same time the circular shape is far more compact than the predecessors’ oval, so visually they look even smaller. It comes with pads in memory foam in three sizes, while the silicone pads of its predecessor have been dropped.

The charging case has also shrunk since the last time, by as much as 40 percent. It is especially the height that has been cut down, and the case now takes up little space in the pocket. It now also supports wireless charging. Sony also makes a point that the box the product is packed in is both smaller and more recyclable than before.

Sony WF-1000XM4 Lifestyle(3)
Sony WF-1000XM4 finally withstands water, with IPX4 certification. Photo: Sony

Better connection

With Bluetooth 5.2, Sony has worked on the connection, and now the sound should not drop out even in areas with a lot of wireless interference. The left and right earplugs are now connected completely in parallel, where the predecessor connected the phone to one plug, which passed the connection on to the next. This also provides a more phase-correct sound reproduction.

The Sony WF-1000XM4 uses both microphones and bone-conducting transducers to reproduce speech. Ill: Sony

Lucid conversation

The conversation sound has improved since last time. The WF-1000XM4 has both microphones and bone-conducting technology, the latter does not pick up sounds from outside the user’s head but only picks up low-frequency vibrations from the cheekbones. All in all, this should ensure the cleanest speech, according to Sony, as the microphones do not have to pick up anything other than the consonants and thus avoid leaking in low-frequency noise from the surroundings.

By the way, you can activate Speak-to-Chat in the app, so that the earbuds pause the music when they understand you are trying to talk to someone.

Features of the WF-1000XM4: Keep this in mind!

Since the earbuds were not officially launched during the test period, I have received a beta version of the Sony Headphones Connect app. I got it for iPhone, which does not support Sony’s superior LDAC codec but which has AAC as the best codec.

Sony Headphones Connect
Remember that Priority on Sound Quality must be activated in the app, to get the best and most airy sound.

In the app, it is important to choose that the earbuds should prioritize the best possible sound, and not the most stable connection, as it does during start-up. Only then will you get AAC sound, and by doing this, the earbuds will also be able to use the LDAC codec on an Android phone – even if that particular phone does not have the app installed. If you do not do this, you will only get the bad SBC codec (standard Bluetooth audio) no matter what phone you have connected.

Sony WF-1000XM4 & Graabein(3)
WF-1000XM4 fits well in the ears of Gråbein. Photo: Sylvia Nordby

Automatic noise processing

In the app you can also select adaptive noise processing. Then the earplugs will calculate whether you are standing, walking, running or using a means of transport – and quiet noise cancellation or hearing based on what situation they think you are in. I must say they hit this much better than before. When I walk, it hears it and activates hearing so I do not go into dangerous traffic. If I am quiet at the PC, it will activate noise reduction to a certain extent, and even though I have not tried public transport yet, it will implement maximum noise cancellation when it finds out that you are on a train, tram, bus or plane.

Sony Headphones Connect
In the app you can activate adaptive noise processing. Then the earplugs themselves – to a fairly large extent – know what situation you are in and what kind of noise cancellation, possibly hear-through, you need.

You can also set manually, and choose whether the noise reduction should also remove wind noise. If you do this, it will use maximum computing power and reduce the battery life somewhat. The noise reduction is on the other hand excellent, perhaps the best I have heard from some earplugs. Sony can do this, and proves it useful with the WF-1000XM4.

You can control the music by tapping the plugs, something I personally have never been very used to. Sony is no better or worse than others here, it’s just a matter of getting to know the system.

Sony WF-1000XM4
Sony WF-1000XM4 comes in black or light grey. Photo: Sony

Sound quality

When I first tested, I was quite disappointed with the dark and woolly sound. Yeah Al that sounds pretty crap to me, Looks like BT aint for me either. A measurement I made through my affordable measuring microphone for headphones, miniDSP EARS, then also confirmed that the WF-1000XM4 attenuated frequencies above 3 kHz.

But after selecting Priority on Sound Quality in the app, and also the DSEE Extreme feature (which tries to recover lost information from compressed audio), it opened up nicely at the top as well.

The drivers use new 6 mm membranes, which should have better dynamics than before. Photo: Sony

Especially with the Android phone and the LDAC codec, the sound was very good. Then the cymbals on Billie Eilish ‘Lost Cause come out crisp and clear, at the same time as the bass guitar rasps nicely in the strings. In addition to the fact that the body in the bass is very large and good.

Beethoven’s Piano Concerto No. 4 reveals that there is still a lack of detail at the very top, as the piano keys do not behave as dancing and playful as with, for example, Bowers & Wilkins PI7. Which also has a bigger and more magical midrange. And where the Sennheiser Momentum True Wireless 2 is a bit made with extra energy at the top, they also work so well that overall I will probably rank them narrowly over the Sony WF-1000XM4.

But the Sonys have better noise reduction, and the speech quality is also very good on the Sonys. Here, their technology clearly works very well, they are definitely in the top tier among earplugs on speech quality.

Sony WF-1000XM4 Lifestyle(6)
Photo: Sony


With the WF-1000XM4, Sony has improved everything its predecessor was bad or mediocre. They can now withstand harsh weather and wind with IPX4 waterproofing, and the Bluetooth connection is impressively stable. The plugs and case are smaller than before, and everything is just prosperity.

Sony loves sound on the full side, and the same is true here. Remember that you must activate Priority on Sound Quality in the app, otherwise you get quite anemic and tame sound with SBC codec. Also activate DSEE Extreme, so you get as much air as possible at the top. Then the sound is nicely balanced, with good dynamics and provides great music experiences.

Overall, the sound is close to, but not as good as, the best competitors. But bring the speech quality, and the Sony plugs will be quite life-threatening anyway.


Sony WF-1000XM4

We think

Very stable connection, excellent speech sound and fabulous noise reduction. Pleasant, rich sound on music. Opens at the top with good audio codecs. In excess subdued in the top register with SBC. Make sure you prioritize sound quality over app stability. 5-band graphic EQ in the app is a bit scarce.

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