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Hifiman HE400i Review 2020 Revision (Headphone)

amirm

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This is a review and detailed measurements of the 2020 version of the popular Hifiman HE400i open back planar magnetic headphone. It is on kind loan from a member and costs US $170.

The new revision is a bit more serious looking with its matt finish:

Hifiman HE400i Review 2020 Revision Open Back Planar Magnetic Headphone.jpg


These are comfortable headphones with their round cups with inside dimension of 58mm diameter. Depth is 26 mm. Weight is on the average side:

Lightest planar magnetic headphone tested.png


Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests. If you think you have an exact idea of a headphone performance, you are likely wrong!

Fitment on the fixture was somewhat variable. I spent quite a bit of time messing with them and what you see is the best I could get.

Hifiman HE400i 2020 Version Measurements
As usual we start with the headphone frequency response as comparison to our preference curve:
Hifiman HE400i Measurements Frequency Response 2020 Revision Open Back Planar Magnetic Headphone.png


I have enclosed the graph for the original version. There is some difference around 2 kHz with the response a bit higher. Whether that is measurement error or variations between units, is hard to say. Not sure why the bass steps down. I messed with it a ton but that step would not go away. The rest of the graph is very noisy unlike any other headphone I have measured. It is even worse than the original. I think these are indication of resonances throughout the response.

Here is relative frequency response for eq purposes:

Hifiman HE400i Measurements Relative Frequency Response 2020 Revision Open Back Planar Magneti...png


The roughness of the response and mismatch between channels will make it more challenging to build an EQ.

Distortion overall is good but we see a lot of wiggles and bumps in there which I think again indicate resonances:
Hifiman HE400i Measurements relative distorion vs Frequency Response 2020 Revision Open Back P...png


Hifiman HE400i Measurements distorion vs Frequency Response 2020 Revision Open Back Planar Mag...png


Group delay is very mess which I think indicates many sound sources mixing up and creating it:

Hifiman HE400i Measurements Group Delay vs Frequency Response 2020 Revision Open Back Planar M...png


And for fans of timing response, here is another graph for you:

Hifiman HE400i Measurements Impulse Response 2020 Revision Open Back Planar Magnetic Headphone.png


Seems like it is swinging up down for a few cycles before settling down.

Finally here is frequency response which remains unchanged:

Hifiman HE400i Measurements Impedance vs Frequency Response 2020 Revision Open Back Planar Mag...png


Hifiman HE400i 2020 Listening Tests and Equalization
The overall sound without EQ is inoffensive. Let's EQ it though and see if we can improve it:

Hifiman HE400i Equalization EQ Parametric 2020 Revision Open Back Planar Magnetic Headphone.png


This is based on the older version EQ which I found to be just as good for this revision. But I spent some time refining it more. Once done, the sound is very good and enjoyable.

Conclusions
Technically the HE400i has fair number of smaller flaws and mismatch with our target. As noted though, out of box response is not bad in that it is mostly missing energy than having too much of it. EQ works but hard to develop a perfect one given the rough response of the headphone. Still, I managed to get very good response out of them.

I am OK with someone buying the HE400i 2020 and use it without EQ. Personally I would only recommend it if you EQ it.

----------
As always, questions, comments, recommendations, etc. are welcome.

Finally took the time to plant some flowers this year and results are great! Latest pick:
Garden Flowers.jpg



Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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  • Hifiman HE400i Review 2020 Revision Frequency Response.zip
    26.4 KB · Views: 59

sweetchaos

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To import this PEQ profile into 'Equalizer APO', use:
Preamp: -9.8 dB
Filter 1: ON LS Fc 50 Hz Gain 6.4 dB Q 1.0
Filter 2: ON LS Fc 99 Hz Gain 2.8 dB Q 1.0
Filter 3: ON PK Fc 1512 Hz Gain 1.0 dB Q 3.0
Filter 4: ON PK Fc 1908 Hz Gain 5.0 dB Q 2.5
Filter 5: ON PK Fc 5280 Hz Gain 3.0 dB Q 3.0
Filter 6: ON PK Fc 8496 Hz Gain -6.0 dB Q 5.0
Otherwise, see my PEQ guide.
..................................................................................................................
For those who don't have PEQ-capable app, and want to use GEQs instead:
See my GEQ guide for 10-band, 31-band, and 127-band GEQ profiles.
 
Last edited:

Music1969

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Hi @amirm

Are you able to do a measurement after you have applied EQ?

Does it actually result in what is expected ? Or some strange behaviour
 
OP
amirm

amirm

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Are you able to do a measurement after you have applied EQ?
Yes but it is a very cumbersome process so I rather not do it unless I have to. :)
 

Music1969

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Yes but it is a very cumbersome process so I rather not do it unless I have to. :)

Noted

Might be useful as part of a wider study

Since you are recommending headphones based on EQ, maybe a wider study to see if the result of such EQ gives expected results or anything unexpected

Sometimes predicted doesn't work out as planned
 

Maiky76

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This is a review and detailed measurements of the 2020 version of the popular Hifiman HE400i open back planar magnetic headphone. It is on kind loan from a member and costs US $170.

The new revision is a bit more serious looking with its matt finish:

View attachment 147932

These are comfortable headphones with their round cups with inside dimension of 58mm diameter. Depth is 26 mm. Weight is on the average side:

View attachment 147934

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests. If you think you have an exact idea of a headphone performance, you are likely wrong!

Fitment on the fixture was somewhat variable. I spent quite a bit of time messing with them and what you see is the best I could get.

Hifiman HE400i 2020 Version Measurements
As usual we start with the headphone frequency response as comparison to our preference curve:
View attachment 147935

I have enclosed the graph for the original version. There is some difference around 2 kHz with the response a bit higher. Whether that is measurement error or variations between units, is hard to say. Not sure why the bass steps down. I messed with it a ton but that step would not go away. The rest of the graph is very noisy unlike any other headphone I have measured. It is even worse than the original. I think these are indication of resonances throughout the response.

Here is relative frequency response for eq purposes:

View attachment 147936

The roughness of the response and mismatch between channels will make it more challenging to build an EQ.

Distortion overall is good but we see a lot of wiggles and bumps in there which I think again indicate resonances:
View attachment 147937

View attachment 147938

Group delay is very mess which I think indicates many sound sources mixing up and creating it:

View attachment 147939

And for fans of timing response, here is another graph for you:

View attachment 147940

Seems like it is swinging up down for a few cycles before settling down.

Finally here is frequency response which remains unchanged:

View attachment 147941

Hifiman HE400i 2020 Listening Tests and Equalization
The overall sound without EQ is inoffensive. Let's EQ it though and see if we can improve it:

View attachment 147942

This is based on the older version EQ which I found to be just as good for this revision. But I spent some time refining it more. Once done, the sound is very good and enjoyable.

Conclusions
Technically the HE400i has fair number of smaller flaws and mismatch with our target. As noted though, out of box response is not bad in that it is mostly missing energy than having too much of it. EQ works but hard to develop a perfect one given the rough response of the headphone. Still, I managed to get very good response out of them.

I am OK with someone buying the HE400i 2020 and use it without EQ. Personally I would only recommend it if you EQ it.

----------
As always, questions, comments, recommendations, etc. are welcome.

Finally took the time to plant some flowers this year and results are great! Latest pick:
View attachment 147943


Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Hi,

Here are some thoughts about the EQ.


Notes about the EQ design:
  • The average L/R is used to calculate the score.
  • The resolution is 12 points per octave interpolated from the raw data (provided by @amirm)
  • A Genetic Algorithm is used to optimize the EQ.
  • The EQ Score is designed to MAXIMIZE the Score WHILE fitting the Harman target curve with a fixed complexity.
    This will avoid weird results if one only optimizes for the Score.
    It will probably flatten the Error regression doing so, the tonal balance should be more neutral.
  • The EQs are starting point and may require tuning (certainly at LF).
  • The range around and above 10kHz is usually not EQed unless smooth enough to do so.
  • I am using PEQ (PK) as from my experience the definition is more consistent across different DSP/platform implementations than shelves.
  • With some HP/amp combo the boosts and preamp gain need to be carefully considered to avoid issues
  • Not all units of the same products are made equal. The EQ is based on the measurements of a single unit.
  • YMMV with regards to the very unit you are trying this EQ on.

Good L/R match.

I have generated two EQs, the APO config files are attached.

Score no EQ: 85.5
Score Armirm: 96.8
Score with EQ: 106.6
Score with EQ Full: 108.3

Code:
Hifiman HE400i APO EQ [email protected] 96000Hz
August172021-093855

Preamp: -5.6 dB

Filter 1: ON PK Fc 32.72 Hz Gain 5.58 dB Q 0.70
Filter 2: ON PK Fc 197.74 Hz Gain -1.81 dB Q 1.29
Filter 3: ON PK Fc 372.89 Hz Gain -2.05 dB Q 1.88
Filter 4: ON PK Fc 961.56 Hz Gain -2.28 dB Q 3.23
Filter 5: ON PK Fc 2099.38 Hz Gain 4.69 dB Q 2.78
Filter 6: ON PK Fc 4973.43 Hz Gain 3.74 dB Q 5.03
Filter 7: ON PK Fc 8649.46 Hz Gain -7.68 dB Q 7.14

Hifiman HE400i Dashboard.png


For those you still think it could be even better (I am not too sure)

Code:
Hifiman HE400i APO EQ Full [email protected] 96000Hz
August172021-095851

Preamp: -9.6 dB

Filter 1: ON PK Fc 13.90 Hz Gain 6.85 dB Q 0.65
Filter 2: ON PK Fc 27.51 Hz Gain 4.80 dB Q 0.66
Filter 3: ON PK Fc 200.55 Hz Gain -1.83 dB Q 1.29
Filter 4: ON PK Fc 401.66 Hz Gain -2.31 dB Q 1.64
Filter 5: ON PK Fc 557.52 Hz Gain 2.46 dB Q 5.35
Filter 6: ON PK Fc 955.81 Hz Gain -2.32 dB Q 3.53
Filter 7: ON PK Fc 2110.63 Hz Gain 4.67 dB Q 2.84
Filter 8: ON PK Fc 4984.70 Hz Gain 5.03 dB Q 7.47
Filter 9: ON PK Fc 8660.27 Hz Gain -7.93 dB Q 7.87

Hifiman HE400i Full Dashboard.png
 

Attachments

Bioguy

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This is a review and detailed measurements of the 2020 version of the popular Hifiman HE400i open back planar magnetic headphone. It is on kind loan from a member and costs US $170.

The new revision is a bit more serious looking with its matt finish:

View attachment 147932

These are comfortable headphones with their round cups with inside dimension of 58mm diameter. Depth is 26 mm. Weight is on the average side:

View attachment 147934

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests. If you think you have an exact idea of a headphone performance, you are likely wrong!

Fitment on the fixture was somewhat variable. I spent quite a bit of time messing with them and what you see is the best I could get.

Hifiman HE400i 2020 Version Measurements
As usual we start with the headphone frequency response as comparison to our preference curve:
View attachment 147935

I have enclosed the graph for the original version. There is some difference around 2 kHz with the response a bit higher. Whether that is measurement error or variations between units, is hard to say. Not sure why the bass steps down. I messed with it a ton but that step would not go away. The rest of the graph is very noisy unlike any other headphone I have measured. It is even worse than the original. I think these are indication of resonances throughout the response.

Here is relative frequency response for eq purposes:

View attachment 147936

The roughness of the response and mismatch between channels will make it more challenging to build an EQ.

Distortion overall is good but we see a lot of wiggles and bumps in there which I think again indicate resonances:
View attachment 147937

View attachment 147938

Group delay is very mess which I think indicates many sound sources mixing up and creating it:

View attachment 147939

And for fans of timing response, here is another graph for you:

View attachment 147940

Seems like it is swinging up down for a few cycles before settling down.

Finally here is frequency response which remains unchanged:

View attachment 147941

Hifiman HE400i 2020 Listening Tests and Equalization
The overall sound without EQ is inoffensive. Let's EQ it though and see if we can improve it:

View attachment 147942

This is based on the older version EQ which I found to be just as good for this revision. But I spent some time refining it more. Once done, the sound is very good and enjoyable.

Conclusions
Technically the HE400i has fair number of smaller flaws and mismatch with our target. As noted though, out of box response is not bad in that it is mostly missing energy than having too much of it. EQ works but hard to develop a perfect one given the rough response of the headphone. Still, I managed to get very good response out of them.

I am OK with someone buying the HE400i 2020 and use it without EQ. Personally I would only recommend it if you EQ it.

----------
As always, questions, comments, recommendations, etc. are welcome.

Finally took the time to plant some flowers this year and results are great! Latest pick:
View attachment 147943


Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
This is a review and detailed measurements of the 2020 version of the popular Hifiman HE400i open back planar magnetic headphone. It is on kind loan from a member and costs US $170.

The new revision is a bit more serious looking with its matt finish:

View attachment 147932

These are comfortable headphones with their round cups with inside dimension of 58mm diameter. Depth is 26 mm. Weight is on the average side:

View attachment 147934

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests. If you think you have an exact idea of a headphone performance, you are likely wrong!

Fitment on the fixture was somewhat variable. I spent quite a bit of time messing with them and what you see is the best I could get.

Hifiman HE400i 2020 Version Measurements
As usual we start with the headphone frequency response as comparison to our preference curve:
View attachment 147935

I have enclosed the graph for the original version. There is some difference around 2 kHz with the response a bit higher. Whether that is measurement error or variations between units, is hard to say. Not sure why the bass steps down. I messed with it a ton but that step would not go away. The rest of the graph is very noisy unlike any other headphone I have measured. It is even worse than the original. I think these are indication of resonances throughout the response.

Here is relative frequency response for eq purposes:

View attachment 147936

The roughness of the response and mismatch between channels will make it more challenging to build an EQ.

Distortion overall is good but we see a lot of wiggles and bumps in there which I think again indicate resonances:
View attachment 147937

View attachment 147938

Group delay is very mess which I think indicates many sound sources mixing up and creating it:

View attachment 147939

And for fans of timing response, here is another graph for you:

View attachment 147940

Seems like it is swinging up down for a few cycles before settling down.

Finally here is frequency response which remains unchanged:

View attachment 147941

Hifiman HE400i 2020 Listening Tests and Equalization
The overall sound without EQ is inoffensive. Let's EQ it though and see if we can improve it:

View attachment 147942

This is based on the older version EQ which I found to be just as good for this revision. But I spent some time refining it more. Once done, the sound is very good and enjoyable.

Conclusions
Technically the HE400i has fair number of smaller flaws and mismatch with our target. As noted though, out of box response is not bad in that it is mostly missing energy than having too much of it. EQ works but hard to develop a perfect one given the rough response of the headphone. Still, I managed to get very good response out of them.

I am OK with someone buying the HE400i 2020 and use it without EQ. Personally I would only recommend it if you EQ it.

----------
As always, questions, comments, recommendations, etc. are welcome.

Finally took the time to plant some flowers this year and results are great! Latest pick:
View attachment 147943


Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

Doodski

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So fortunate, nothing is growing in Massachusetts this year
The Canadian Prairies this summer have had the worst crop growth in a longggg time due to drought. Farmers are saying between nothing and 35% of crops are salvageable. So wheat, canola and other stuff including feedstock. Farmers are taking their animals to auction because they can't feed them.
 

Bioguy

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The Canadian Prairies this summer have had the worst crop growth in a longggg time due to drought. Farmers are saying between nothing and 35% of crops are salvageable. So wheat, canola and other stuff including feedstock. Farmers are taking their animals to auction because they can't feed them.
That’s awful, add food shortages to the list of worries
 

Doodski

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That’s awful, add food shortages to the list of worries
As the colloquialism goes, "Sheit runs downhill." The poor will take the brunt of the cost of living increase and shortages. Canada being a major wheat exporter will not be able to satisfy the needs of some poor countries. I guess it's $1 chocolate bars and 97 cent potato chips at Walmart from now on. :D
 

A Surfer

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Absolutely. I was a climate activist for years and back in the early 2000s I used to get up on my soap box and talk about how people will take climate change seriously when the areas of the world that we call bread baskets because they grow so much food start to have problems producing, look out. California is burning and in drought which is scary as California produces so much food. Better hope the drought doesn't start spreading there.

I like to say that one day farmers will be the rockstars of the world again and we'll pay a whole lot less attention to (and hopefully less money to) people who program apps for phones that really don't make a whit of difference. The most prized skillsets will be those who can grow food and engineers who can really start cleaning our spoiled water supply and formerly healthy farmland. The city of Toronto for instance has consumed some of the very richest farmlands where once food was grown only to be replaced with urban sprawl. Not a fair trade in my view.
 

A Surfer

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If people want to see a somewhat relevant and also somewhat hopeful documentary watch How Cuba Survived Peak Oil. You should be able to find it on YouTube. Might be some important lessons there for all of us. I am a huge proponent of urban agriculture, and in particular, green roofs.
 

Doodski

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The Lower Mainland Fraser Valley area (From Vancouver to Hope BC) is some of the best farmland around and it is slowly being consumed with housing too. Calgary too is expanding into farmland. Not sure how much longer that will continue as Calgary is in a slump.
 
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