This is a review and detailed measurements of the Hifiman HE6se planar magnetic headphone. It is on kind loan from a member and costs US $1,800. I had previously reviewed the now discontinued
Hifiman HE6 so great to see how the replacement performs.
The HE6se distinguishes itself with new headband, cups, etc.:
View attachment 131031
Very unusual ultralight "tube like" cable comes with the headphone:
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It has a clear silicone like outer jacket and possible Litz wiring inside. It crackles unfortunately right by the connectors but otherwise works well.
I had to extend the headband to max to get it to fit on my measurement fixture and my head. So if you have larger head, be sure you can try it out and return if you don't get good fit. This also caused a bit of undue pressure on my ears/head. It is not bad but it is not as comfortable as I remember the HE6 being.
The H6se is the second heaviest headphone I have tested so far (since I started to keep track):
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Cup dimensions are 57x57x22 mm (height x width x depth). Note that the cup depth is asymmetrical so that is approximate.
The measurements you are about to see are made using a
standardized Gras 45C. I searched for any and all measurements I could find online. Alas while a number of them are close to mine, none are using the exact fixture down to coupler and pinna. As you will see, I have confirmed the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers specially in bass and above a few kilohertz so keep that in mind as you read these tests.
Hifiman HE6se Measurements
As usual we start with our frequency response:
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The overall signature is very close to the He6 with its dead flat bass and mid-range response and shortfall after that. There is a bit less peaking around 4 kHz. From then on, there is similarity but measurement accuracy drops off especially with new pad and such.
Relative frequency response to target guides us in developing equalization curve:
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The HE6 had very low distortion. The HE6se bests that yet again:
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Other than a couple of peaks at 114 dBSPL, this headphone doesn't seem to know the meaning of distortion!
We have a bit exceeding our 40 dB threshold but we have a bit of peaking there so we can pull that down and lower its impact:
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Group delay shows good response in bass and usually fuzziness in midrange in this class of headphone:
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This is very different than HE6 as it would be due to different cup configuration.
What was a puzzler was headphone impedance:
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Company spec is 50 ohm which matches that of HE6. They say the same driver is used so we should be getting the same impedance but I am seeing 64 ohm. This is an automated test so not sure how there can be this much error. Wonder if newer drivers are a bit different.
Sensitivity is a bit lower but that could be sample to sample variation:
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Then again it could be due to higher impedance of the driver.
Hifiman HE6se Listening Tests and Equalization
I listened for a few seconds and then selected my HE6 preset in Roon. The positive transformation was unmistakable. Everything improved across the board. However, the sound had a bit of brightness that surprised me. I made one slight adjustment to 4 kHz region but did not make much of a difference. The biggest improvement came from optimizing the bass EQ:
View attachment 131048
With HE6, I just threw a shelving EQ at it and it made such a positive difference that I did not try to optimize it further. I did that now and boy did it balance the sound nicely and gave me that gorgeous sub-bass with incredible resolution and fidelity.
To give you an idea how good it now sounded, I could not weight to take a picture of the HE6se so that I could wear it again and listen to the rest of my playlist!

This is one of my reference tracks that sounds so gorgeous on this headphone:
Conclusions
Many movie sequels are terrible. It is good to see that Hifiman has more or less resurrected the HE6 in the HE6se. Overall characteristics remains and with some EQ, it sounds incredibly good with its great bass capability and near absence of distortion. For me personally, it doesn't fit as well so it wouldn't be something I would purchase but you may think otherwise.
Overall I am going to happily recommend the Hifiman HE6Se with equalization. Even without EQ, it can be a fine choice. But why settle for that???
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