This is a review and detailed measurements of the Sony WH-1000XM4 noise cancelling, closed back headphone. It was kindly purchased by a member from Amazon and drop shipped to me. It costs US $278 including Prime shipping.
It comes in three colors; this one is black:
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I like the feel of the unit. Seems high quality. The detents in the slide mechanism is not strong so adjusting it was a bit of a pain.
This headphone has 1000 features which I won't be covering here but as a quick example, has a proximity sensor in one of the cups so it can shut itself off when you take it off your head.
There is a cord to use it hardwired without the unit being on but as you will see, the story here is complex.
These are the dimensions:
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Note: The measurements you are about to see are preformed using
standardized GRAS 45CA headphone measurement fixture. Headphone measurements require more interpretation than speaker tests and have more of a requirement for subjective testing as a result. In addition, comparison of measurements between different people doing it using different configurations requires fair bit of skill. So don't look for matching results. Focus on high level picture. Listening tests are performed using
RME ADI-2 DAC and its headphone output.
Fitting the WH-1000XM4 on the measurement fixture was very challenging. Slightest movement and variation would make a large change in response. I got lucky in that all of a sudden, both channels locked together indicating at least balanced mounting. So that is what I ran with. I suggest you look at the high level picture per above even more than usual.
Sony WH-1000XM4 Measurements
As usual, let's start with the WH-1000MX4 frequency response in passive mode (electronics turned off):
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Ouch, ouch, ouch! What on earth is that huge hump between 100 and 200 Hz? That, combined with the large dip between 2 and 3 kHz is going to make this sound muffled and unpleasant.
Switching the unit on causes massive transformation for the better:
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Levels shifted way up and I forgot to compensate for it. So imagine the curve is pulled down a few dB. Then you see that the bass response is more or less is following the preference target. We still have a peak around 800 Hz to deal with and the same dip around 2 kHz but we are much closer to where we need to be.
I guess this confirms that Sony knows the response is broken without DSP and left it that way assuming (correctly) that most people will use this with noise cancellation on. And if Sony can fix the bass with EQ, so can we!
From here on, I am going to show the passive performance until we get to listening tests. Here is our relative response:
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Can you say deeply colored? I knew you could. We have whopping 24 dB deviation from our target. No matter which way you skin this, and how much inaccuracy you want to read into the measurements, this is way off any kind of proper frequency response. Pretty sure this is the worse we have seen so far in any headphone.
Distortion is present but at low levels, it should be OK:
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Impedance is both low and variable:
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As noted, the moment you turn on the headphone, it becomes a different animal because then you are feeding the input of the ADC and the internal amplifier is then driving the headphone. Sadly, because the internal amp is battery powered, it is anemic and can severely distort if you turn it up way . The headphone is efficient though so not a concern in everyday listening.
Efficiency is quite high which is good:
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Finally, group delay tells us something is amiss in the response that is causing that large peak in upper bass:
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Sony WH-1000XM4 Listening and Equalization
One listen to the headphone off and you would want to put it down. It is just so unpleasant as far as tonality. I can't even describe it in words. So let's not suffer too much and apply EQ to fix what ails it:
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You can see the large amount of correction I had to apply to it. It took it though and it started to sound quite "normal" and pleasant. I could listen to it for hours this way.
As I noted earlier, I did not have level compensated measurements for when noise cancelling is on. Fortunately as it is, the sound is fairly good. Gone is the recessed and cluster phobic sound of when the unit is off. As such my equalization is slight:
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As I noted in the measurement section though, distortion increases at higher levels so I would personally opt to use the passive with EQ when at the desk.
Speaking of noise cancellation, I did a quick test of that (not set up yet for formal, objective tests). As usual, these headphones rely on "belts and suspenders" principle by isolating noise passively as much as they can and then use noise cancellation. I used my very noisy Audio Precision analyzer as stimulus. Just wearing the headphone with it off, it got rid of 80% of the noise. What was left was naturally lower frequencies that are harder to filter. Once I turned on NC, it zeroed that noise out like it never was there.
Note that the active mode had no effect on non-repetitive noise sources such as my wife working downstairs, doing dishes, etc.
Conclusions
The Sony WH-1000MX4 is a highly flawed headphone in passive mode. It would get one of the worst scores in my book in that mode. It simply is not listenable. Noise Cancellation thankfully improves on that so much that you could use it without further EQ. Unfortunately you are then limited by the power ability of the internal headphone amp so know that it won't get ear bleeding loud. Equalization cleaned up the response of passive mode substantially so if you have that available, then you are in good shape.
Overall, I am going to recommend the Sony WH-1000MX4 if you apply equalization. Without it, the active mode would barely get a nod from me as well.
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