Review written by Andrew Park (@Resolve)
I don’t normally recommend noise cancelling headphones to people unless they’re in certain environments where this feature is essential. It’s important to remember that many people use headphones on the go, while on transit or in places where there’s a lot of ambient noise. And, for these purposes, noise cancelling headphones may be the best solution. But there are also some issues with noise cancelling tech in general that I often worry about. The first is that in traditional examples, using ANC (Active Noise Cancelling) introduces additional noise floor - kind of like a mild hiss in the background. The second issue is that while effective, the noise cancellation can introduce some artifacts or burbles in the treble. How significant these issues are varies depending on the headphones, but so far this has been an obstacle for me.
The Sony WH-1000XM4, however, is a brand new ANC headphone that manages to significantly improve on these issues, boasting some of the best noise cancelling tech available. The big question in my mind now is, is the lack of ambient noise significant enough for enhance the sonic perception of the music being played - and is this something I can finally get into?
- Type - Closed, dynamic
- Driver - 1.57 ", dome type (CCAW Voice coil)
- Diaphragm - Aluminum coated LCP
- Sensitivities (DB/MW) - 105 dB / mW (1 kHz) (when connecting via the headphone cable with the unit turned on), 101 dB / mW (1 kHz) (when connecting via the headphone cable with the unit turned off)
- Battery Charge Time - Approx. 3 Hours (Full charge)
- Battery Life - Max. 30 hours (NC ON), Max. 38 hours (NC OFF)
- Battery Life (Waiting) - Max. 30 hours (NC ON), Max. 200 hours (NC OFF)
- Bluetooth - Version 5.0
Build, Design & Comfort
In general I quite like the build and design of the XM4. It’s small, portable, with oval shaped pads that are extremely cushiony. So it’s comfortable for the most part - with one exception. I find that because the cups aren’t very big, they tend to scrunch my ears up a bit when I wear them. This isn’t a huge problem, but for longer sessions it can be somewhat bothersome. Of course, this may be more to do with my personal ear shape and less to do with the headphones, you may not have any issues with this.
Of course, the XM4 is filled to the brim with additional features, not just the noise cancelling. Many of these border on gimmicks, but I find myself using a number of them regularly and really appreciating them.
In particular, the XM4 has a sensor that detects when you take the headphone off, pausing your music, and then resuming playback when you put it back on. This introduces some acoustic challenges that'll discuss later on, but the feature itself is really useful. I also appreciate the ability to pair the XM4 to multiple devices at the same time, so I can have it connected to my phone and then seamlessly switch to using it with my computer without having to unpair anything.
This on its own is such a useful feature that I think going forward it should be included in every wireless headphone. What surprised me most about this feature, however, is that when switching to using it on my computer, I found that the XM4 retains the EQ profile I had specified in the mobile app software. This is great for when you get into specific adjustments and custom profiles - which I highly encourage for anyone who is looking to buy this headphone (or if you already have it)
The Sony WH-1000XM4 uses a dynamic driver, but importantly it’s also a closed-back, wireless, active noise cancelling headphone. This means in addition to the moving coil transducer the cups contain a considerable amount of additional electronics. In particular, the 'in-use' sensor on the left side creates asymmetry on the inside of the cups, and this does show up in the measurements.
For sound evaluation, I should also note that the headphone comes with a standard 3.5mm connector as well if you’ve run out of battery, but it also performs somewhat differently when being run passively or actively.
When it comes to detail and image clarity, the XM4 is nothing special - as we may expect from such a feature-rich headphone. In fact, it doesn’t even compete all that well when compared with less expensive closed-back headphones, and is easily beaten by the similarly priced Audeze Mobius (and its various iterations). This is an important comparison because the Mobius is also a wireless, closed-back headphone with lots of features.
Conveniently, the XM4’s active noise cancelling function performs exceptionally well. In noisy environments, using the XM4 with its noise cancelling turned on is bound to give you a better sense of clarity for your music, but that’s really just because of how well it eliminates the noise floor. Make no mistake, this is by no means an audiophile headphone when it comes to detail and technicalities.
Speed & Dynamics
For speed, the XM4 is once again a bit on the sluggish side. The sense of immediacy for the initial leading edge isn’t particularly strong, meaning that tones lack the kind of tightness and control that makes music engaging with great headphones. Once again, this is done far better on the Audeze Mobius. The lack of control also isn’t done any favors by the XM4’s frequency response, which we’ll get to shortly.
For macrodynamics, the XM4 is surprisingly decent. They provide a sufficient sense of punch and impact to the music, and while this may be artificially enhanced by the headphone’s bass emphasis, even when EQ’d to a more appropriate level, the XM4 still delivers some decent slam. Once again, it’s not on the level of some similarly priced dynamic driver headphones (I have the Drop TR-X00 Ebony here for comparison), but it’s still decent.
Soundstage & Imaging
For soundstage and imaging I’m pleasantly surprised by the XM4. No it’s not particularly spacious, but for a small closed-back headphone it’s really not that bad. Instrument separation and placement is also acceptable, but because it lacks the image clarity and speed of other more technically capable headphones, the XM4’s image distinction isn’t as well defined as other headphones. The Audeze Mobius wins again in that department, even though I’d give the overall spaciousness edge to the XM4.
For material and transducer related timbre, the XM4 sounds reasonably normal with a very minor exception. When active noise cancelling is turned on, while excellent, there’s still the ever so slight parasitic background noise. Now to be fair, it’s way better on the XM4 than I’ve heard on other ANC headphones, but that artificial de-noising burble is still ever so slightly audible in some environments. So while not exactly an issue with the timbre - at least traditionally speaking - the experience isn’t the most ‘organic’ or natural in that sense.
For frequency response related timbre, there are some tonal shifts due to a significant 5-6khz peak. This is mainly problematic for cymbal tones, but it’s also a bit overshadowed by the compressed and congested sound of the overbearing bass bleed. Thankfully there is a built-in EQ function that users can play around with to try to improve things, and so we’ll go through how to make this headphone sound more appropriate than its default tonality.
Frequency Response & Tonality
The following is how the Sony WH-1000XM4 measures on the GRAS 43AG standardized measurement rig relative to the combined Harman target curve (Harman 2013 bass but Harman 2018 mids and treble). For reference, the Harman 2018 bass is substantially elevated - far too much for what I think most audiophiles would consider appropriate, even if some bass heads may like it, so I prefer to use the more modest 2013 bass shelf. In any case, these are raw measurements, meaning it should not look like a flat line across. This instead shows the raw measurement relative to the target that would otherwise be normalized in compensated measurements.
How do you read this? The dotted black line is the target (how we might want it to measure), and the green line is how the headphone in question measures. Effectively, this shows how significantly the headphone’s frequency response deviates from the target.
Default - Analog
Using the analog connection, I found the XM4 to have a noticeable channel imbalance at various points. This is to be expected with feature-rich wireless headphones, but in the case of the XM4, it’s particularly bad. This is likely due to the extra sensor that exists on the inside of one of the cups to determine if the headphone is being worn, and this allows it to automatically pause and resume the music when taking them off and putting them back on. This is a cool feature, but it also makes it so that when the battery runs out, you’ll likely end up with a bit of an incoherent channel imbalance going on.
Thankfully, this is significantly improved when using it wirelessly with bluetooth.
I find the XM4’s default tonality to be both boomy and aggressive at the same time. In general the XM4 has a significant ‘V-shaped’ tonality, but apart from that there are two major problem areas to pay attention to.
The first issue is of course the bass elevation - but it’s not the overall bass level I’m going to be critical of here. Lots of bass presence is fine, the problem with this headphone is that the bass shelf extends up past 250hz with a massive boost in the bass to mid transition. This makes everything sound thick and muddy, boomy and overbearing. Things are made worse by the substantial V-shape, which on its own isn’t that bad to have, but I would have preferred the mids to be more filled in by default and then use the V-shaped tuning option in the mobile app to get it to be more flavor oriented.
The second major issue to my ear is the 5-6khz peak. Now I have to stress that while this isn’t exactly sibilant (this would be more of an issue around 7-9khz), it does cause some problems for percussion compression and it can come across somewhat aggressively in general. The rest of the treble is decent, even though I do hear a slight ‘shimmer’ around 10khz but it’s not too bad.
So the V-shape in this isn’t what I’d consider to be a desirable one, and while there is some pinna gain in the upper mids (better than nothing), it’s overall tonality ends up being more suited to catch the attention of anyone listening to them in a store rather than something you might want to listen to for long periods of time.
The nice thing about the XM4 though is that it’s meant to be used with a phone and with Sony’s headphone app, you do get a number of EQ presets and you can make your own as well.
Unfortunately most of the presets just make things worse on the XM4, however there were two that stood out to me as an improvement over the default tonality. The first of which is the ‘Vocal’ preset.
While still V-shaped and still somewhat aggressive in the treble, it does a lot to bring the bass response back in line to a more appropriate level. It’s still not perfect, but this helps reduce the boomy and overbearing bass issues, providing a bit more definition both for the bass and clarity for the transition to the lower mids.
The second preset that stood out to me was the ‘Bright’ preset. This one actually made the treble aggressiveness worse, however it did a lot to fix the bass response, and then added a bit more presence in the mids and upper mids. I think this would primarily be suitable for jazz and classical music, because the 5-6khz peak is accentuated a bit as well. But for those genres this is still more agreeable than the default tonality.
Custom Preset (App)
My favorite aspect of the XM4 though - apart from the excellent noise cancelling - is the ability to create a custom EQ preset in the mobile app. While you don’t get enough tuning control for areas that really need to be adjusted (like 100-200hz), you do get a few filters that allow you to make this a decent sounding headphone.
I found the above settings to be the most agreeable to my ear, and this also gets the XM4 a bit closer to the target. In theory it’s possible to reduce the bass further by going negative on the ‘Clear Bass’ slider, but this only really influences frequencies below 80z - a region that really isn’t that bad on the XM4 to begin with. What I’d love to see is an update to the software that adds more EQ bands, or at least shift the 400hz option down to 200hz.
Of course, I prefer to just use Equalizer APO with the PEACE UI because it provides that extra flexibility. The following is what I ended up with when EQing the XM4:
- 42 - Peak filter -2, Q = 1.41
- 120 - Low shelf -6
- 200 - Peak filter -3.5, Q = 1
- 1000 - Peak filter +3.5, Q = 2
- 1352 - Peak filter -1.4, Q = 2.5
- 2252 - Peak filter +6, Q = 2
- 3000 - Peak filter +2, Q = 2.5
- 4000 - Peak filter -1.4, Q = 2.5
- 5100 - Peak filter -4, Q = 2.5
With this adjustment the XM4 now measures a lot closer to the 2018 Harman target. I wanted to retain some of the bass emphasis, because I think a lot of people will be buying the XM4 specifically for extra bass (given common trends in consumer-oriented headphones). To my ear, this adjustment makes the bass a lot more distinct and well represented, along with additional clarity and balance to the mids. I also took down some of the sharpness around 5-6khz.
Unfortunately I wasn’t able to compare side by side with the AKG N700nc or the Bose QC35ii, so these may have to wait for another time. But I should state that among all the ANC headphones I’ve tried so far, the Sony WH-1000XM4 has some of the very best noise cancelling functionality. So if noise cancelling is your priority, the XM4 is worth strong consideration.
Audeze Mobius - $399
If you don’t need noise cancelling, but you’re still looking for a wireless, closed-back headphone, the Audeze Mobius is a far better option. It’s better both in terms of technical performance and in terms of tonal balance. Of course, the Mobius is a planar magnetic headphone, and so it’s also a bit heavier. But in general they’re both quite comfortable, and I find this really just comes down to how significant the noise cancelling feature is for you.
While the Sony WH-1000XM4 has some of the best noise cancelling and features of any wireless closed-back headphone I’ve used, it unfortunately trades off in terms of sound quality to a significant degree. Its default tonality is a boomy yet aggressive sounding experience that isn’t done any favors by both its frequency response or its technical ability.
However, with the use of Sony’s mobile headphone app or a custom EQ profile like the one provided above, the XM4 becomes a more interesting proposition. The noise cancelling alone on this headphone is some of the best I’ve yet heard, and in some environments this may give you a better ‘picture of the music’ than what you might get with more traditional audiophile wired headphones.
But in more optimal listening environments, there are much better sounding wired closed-back options for much less money.
Watch the video review here:
-Andrew Park (@Resolve)