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Neumann NDH20 Review (Headphone)

amirm

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This is a review and detailed measurements of the Neumann NDH20 closed back headphone. It was kindly sent to me by a member and costs US $499.

The NDH20 is an attractive and solidly feeling headphone:
Neumann NDH20 Review Closed back headphones.jpg


It weighs slightly above average but per above, it felt fine wearing it:

lightest headphone review.png


The removable headphone cable is light but has this spring action to it that was annoying. I literally had to put something on top of it on my desk to keep it from interfering with my mouse.

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 VERY difficult. It would not fully surround the artificial ear, and I could not get it to fully seal no matter what I did. Slight movements and changes would vary the levels but in practice, I noticed frequency response did not substantially change. Still, be on notice that my confidence in measurements are not super high (although EQ settings verified that they were good enough for that purpose).

Neumann NDH20 Measurements
Let's start with our usual frequency response:

Neumann NDH20 Measurements Frequency Response Closed back headphones.png


I was quite surprised by this response. Given Neumann's heritage for neutrality in speakers, I expected a flat and bass shy response. Instead we have plenty of bass but then a suck out in the 1 to 3 kHz. We also have a deep cancellation around 2.6 kHz. I am not used to seeing such at such a low frequency. Relative response therefore shows somewhat a "V" response:

Neumann NDH20 Measurements Relative Frequency Response Closed back headphones.png


Distortion is very good considering that we don't need to boost the bass where it rises:

Neumann NDH20 Measurements Relative distortion Closed back headphones.png


Neumann NDH20 Measurements THD distortion Closed back headphones.png


Something is definitely not right around 2.5 to 3 kHz though. We see the same in Group Delay:

Neumann NDH20 Measurements  Group Delay  Closed back headphones.png


It seems like a strong resonance of sorts out of phase with the response of the driver.

Impedance is middle of the road and mostly fixed:

Neumann NDH20 Measurements Impedance Closed back headphones.png


Sensitivity is decent:

Most sensitive closed back headphone review.png


Headphone Listening Tests
First impression is not bad. You can hear the emphasis in bass and also some accentuation of highs. It is not until you dial in some EQ that you realize the imbalance:

Neumann NDH20 Equalization  Closed back headphones.png


I had to play a lot with these dials as the sound wound up being too bright after my initial correction. I was mostly happy with it but not quite there. It is possible some would prefer the heavier bass response.

Sub-bass response as you would expect is excellent.

Conclusions
This was a surprising outcome from Neumann. I expected a more neutral headphone but instead got a bass heavy one. Even though I am a fan of bass, it needs to be balanced relative to the rest of the response. I find that when the 1 to 3 kHz is sucked out, the sound becomes closed in which is a death sentence in my book for headphones as they already bad in that regard.

Equalization helps a lot but needs more refinement to get to a good place.

I can't recommend the Neumann NDH20 without EQ. With EQ, it barely gets there.

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

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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sweetchaos

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To import this PEQ profile into 'Equalizer APO', use:
Preamp: -4.8 dB
Filter 1: ON PK Fc 140 Hz Gain -2.0 dB Q 2.0
Filter 2: ON PK Fc 2000 Hz Gain 5.0 dB Q 4.0
Filter 3: ON PK Fc 3400 Hz Gain -3.0 dB Q 4.0
Filter 4: ON PK Fc 8447 Hz Gain -4.0 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.
 
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MikeJ

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@amirm Not really sure about your THD/FR measurements. Neither Head-fi nor Sonarworks who both measured these, have that strange 2.6kHz artifact in their measurements, in both FR/THD. I personally don't hear the suckout too. Maybe you measured a pair which could possibly have some QC issues? Or maybe Neumann representatives can come here and elaborate on this? Your results look really strange to me.
 

usern

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I was looking forward to this review. I need comfortable closed back low distortion headphone and NDH20 was on my short list. Now I'm leaning towards K371 due to that big dip at 2.6k for NDH20.
 
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amirm

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@amirm Not really sure about your THD/FR measurements. Neither Head-fi nor Sonarworks who both measured these, have that strange 2.6kHz artifact in their measurements, in both FR/THD.
That's because they smooth the response too much which wipes out such sharp dips. They do show the same broad response error.
 
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amirm

amirm

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I personally don't hear the suckout too.
The suck out itself is too narrow to be audible. The broad region that is deficient is most definitely audible and shown in other measurements.
 

MikeJ

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I was looking forward to this review. I need comfortable closed back low distortion headphone and NDH20 was on my short list. Now I'm leaning towards K371 due to that big dip at 2.6k for NDH20.
I suggest you better wait for explanation. There is obviously something wrong with these measurements (or this particular measured pair). Neither Head-fi, nor Sonarworks, nor Sbaf do show this FR dip/THD artifact. It's too soon to make proper conclusions I think.
 

MikeJ

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That's because they smooth the response too much which wipes out such sharp dips. They do show the same broad response error.
Yeah but your sharp dip shows only in left channel, doesn't it? Really interesting...
 
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amirm

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Expanding, I have made a trade off between filtering and leaving enough resolution there so that we can identify engineering faults. Per above, our auditory filters are too broad to detect that sharp cancellation. But leaving it in the response shows that there is a problem there that should have been caught and resolved.
 
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amirm

amirm

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Yeah but your sharp dip shows only in left channel, doesn't it? Really interesting...
No, it shows up in both. It is more accentuated in one given the vagaries of headphone measurements.

1633901225393.png
 
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amirm

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Here is the same measurement smoothed to 1/3 octave:

1633901424964.png


We see the cancellation is completely filtered out now.
 

MikeJ

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If only I can ship my pair to you (from EU), that would be awesome to compare. Anyway thanks for doing this.
 

pozz

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@solderdude Can you please comment on the cancellation? I have seen a similar thing in your measurements, even though it might be unrelated in this case.
 

MikeJ

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Here we go again…
You know what? I have seen two different measurements of two fresh pairs of one popular headphone (will not name it for obvious reasons) and guess what? They were different to the extent that one pair was RMA'd as defective unit. But let's not derail this thread.
 

greenpsycho

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You know what? I have seen two different measurements of two fresh pairs of one popular headphone (will not name it for obvious reasons) and guess what? They were different to the extent that one pair was RMA'd as defective unit. But let's not derail this thread.
So it actually happened exactly once? He's just saying, cuz literally everytime there is a bad measurement 50% of the comments are "oh it must be a defective unit"

And it rarely actually is.
 
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