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NAD Viso HP50 Review (headphone)

amirm

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#1
This is a review and detailed measurements of the NAD HP50 headphone. It was kindly purchased new by a member and drop shipped to me. While NAD still lists this headphone, it doesn't seem to be available at retailers. Instead, there are some being sold on ebay. I think new they were going for $300 but ebay seller has certified refurbished for $179 normally. But apparently they frequently go on sale down to just $89 which is what the member paid. The packaging and headphone look brand new so they must be clearance stock.

I like the modern look of the headphone:

NAD Viso HP50 Review.jpg


Notice how the two cups are hanging differently from each other. This is because the headband is not symmetrical. This, combined with rather small cups made getting consistent results between the two channels impossible. Also, when you expand the headband, it will become rather square, giving you a Frankenstein look. My monitor is not reflective so I was good with that!

An interesting twist on this headphone which I appreciated is that you can plug in its diminutive cord into either headphone socket:

NAD HP50 Review.jpg


The cord is ultra light but very short. I guess it is made for portable use. I managed to pull it out of my amplifier as I moved around. Fortunately you can replace it yourself with a longer cord.

NAD Viso HP50 Measurements
I was surprised to see the frequency response of the HP50 having such a big shortfall in the upper midrange/treble region:

NAD Viso HP50 frequency response measurements.png


From testing countless speakers with deficiency in this area I can tell you that it takes the fun and sparkle out of your music.

Judging bass response is a crapshoot due to highly challenging fit to my Gras 45C artificial ears. Slightest movement would make the response vary a ton. And due to headband expanding asymmetrically, you couldn't get both cups to fit properly at at the same time and at low and high frequencies. So the above is a sample fit and we need to use judgement in equalization.

Going with what we have, this is our deviation from our preference target curve:

NAD Viso HP50 frequency response measurements vs target.png


As see, the variation is quite large so no sense in bickering about the preference curve. No matter how you look at it, this headphone has a sucked out response in that region.

There is some peaking around 12 kHz but it is narrow. Since my test fixture de-emphasizes that region, I think it may merit a bit of correction.

Distortion is very low in bass and in general if you don't get the thing too loud:

NAD Viso HP50 Measurement Distortion Ratio.png


It is interesting to observe those narrow peaks.

In absolute terms and using 94 dBSPL at our reference, distortion is comfortably below my threshold of 40 dBSPL:

NAD Viso HP50 Measurement Distortion.png


Group delay is somewhat instructive here, showing discontinuities where we have some frequency response variations:
NAD Viso HP50 Measurement Group Delay.png


Otherwise it gives us license to equalize the response as we see fit especially in the 1 to 10 kHz region. There are no sharp spiked that would tell us otherwise.

Impedance is more or less flat:

NAD Viso HP50 Impedance Measurements.png


When you look at my headphone measurements, you should look at the performance relative to 33 ohm load I use for testing as that is the closes match.

Sensitivity is excellent meaning you need very little power:
Most efficient headphone review.png


NAD HP50 Headphone Listening Tests
Out of the box, there is nothing offensive about the sound. We could have told this from the frequency response as not much exceeds our target response and distortion is quite low. After a few seconds of adjustment, you notice the closed, bass heavy sound. So let's not waste more time and apply some judicious correction based on frequency response:

NAD HP50 EQ Equalization.png


The filters make substantial improvements with the exception of the 12.1 kHz one. You could leave it out if you wanted.

Wow, what a transformation. This thing takes to equalization like a duck takes to water. Not only do we have beautiful bass, midrange and treble now, it is all squeakily clean. And as a huge bonus, spatial qualities (i.e. "soundstage") improve substantially since a lot of stereo cues are in the 1 to 5 kHz we have boosted.

Don't quote me on this -- I like to get paid if you do! -- but I think this headphone has angled drivers? If so, that and equalization must be behind the open, oval sphere above your head and on each side. Panned instruments position themselves to the left and right while the mono vocals take front top center stage. Not Sennheiser HD800S category but we are talking about some of that flavor.

I have to tell you, post equalization I did not want to stop listening to the HP50! As a matter of fact it is the next day and I am listening to it as I am typing this review!

A word on comfort: it seems to have loosened up a bit today and become more comfortable. Yesterday I would rate it at 80% comfort. Had to take my glasses off since the headphone relies on rather strong clamp pressure to stay on your head. The headband stays proud even at the lowest extension of the cups. So personally I am not sure if I could use it all day if it did not continue to loosen up.

Sound isolation is good but not as good as my larger closed headphones.

Conclusions
What a hidden jewel post equalization! At sale price of $89 it is a steal relative to its smooth, low distortion and quality of sound it provides. It is not as comfortable as large cups on higher end headphones but you may be OK with it. With the high efficiency you should also be able to drive these with many portable devices.

All this said, I can't recommend the NAD HP50 without EQ. With EQ however, I am here go give it a strong recommendation especially considering the price. Heck, I would even take the price out of the equalization!

------------
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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BillH

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#2
Nice! I think this is our first headphone diamond in the rough.

It's interesting in the frequency response plot how the two earphones seem to trade off mid-range boost for low frequency boost.
Does anyone give me a simple way to understand this - better sealing versus poor seal kind of argument?
 

wwenze

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#3
Asymmetry problem not mentioned in others' reviews of the same headphone... could it be due to $89 price tag?

Or is it just due to being flexible + aging which is a non-issue.

Rting could bend their unit until like this

https://www.rtings.com/headphones/reviews/nad/viso-hp50
 
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amirm

amirm

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Thread Starter #4
Or is it just due to being flexible + aging which is a non-issue.
I did not want to twist my sample since it is not mine. I did put a bit of pressure on it but it snapped back. I think the structure it has makes it impossible for it to hold its shape symmetrically. Fortunately for listening it is not an issue.
 

sweetchaos

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#6
If you're using Equalizer APO:
Preamp: -10.5 dB
Filter 1: ON LS Fc 35 Hz Gain 5.0 dB Q 1.0
Filter 2: ON LS Fc 80 Hz Gain 5.0 dB Q 1.0
Filter 3: ON PK Fc 2100 Hz Gain 2.5 dB Q 2.0
Filter 4: ON PK Fc 2811 Hz Gain 7.0 dB Q 2.0
Filter 5: ON PK Fc 12100 Hz Gain -5.0 dB Q 4.0
For more info, see List of Amir's Headphone PEQ filters.
 
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#7
There was an interesting short video from InnerFidelity about these headphones, and the whole philosophy behind designing them. I don't know if what was said holds any merit though.

 
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#9
@amirm
I appreciate the "crapshoot" measuring bass response, but are you finding most headphones have this wide FR differential between left and right channel? A varying differential extends to 5.3kHz as you noted, but as the wavelengths get longer going down in frequency, any asymmetrical fitment shouldn't widen that differential (or perhaps I am mistaken? I am just thinking any distance differential from mic on each side will cause even SPL drop at any given frequency since SPL drops off by inverse square law). To me, it seems these HP are a bit 'off' as far as channel balance, which perhaps was masked or explained away by NAD opting to sell with an asymmetrical fitment, or perhaps there's some other reason.

I wonder if we had a way to place on a symmetrical headband if we'd still see these measurements. Any thoughts? Is the asymmetrical headband/fitment a QC issue in manufacture?

For me, I would not go near these as I prefer to DSP to be icing on the cake (fine tuning) rather than a blunt instrument to get something responding in the right ball-park.
 
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amirm

amirm

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There was an interesting short video from InnerFidelity about these headphones, and the whole philosophy behind designing them. I don't know if what was said holds any merit though.
Basically he is saying to boost bass which makes sense. Question is if that was done, or the mids were taken down to give that impression. Either way, hearing Tyll say they sound wonderful without EQ is quite puzzling.
 

Blumlein 88

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#11
I thought this phone was one of the first to be designed with the Harman headphone research in mind. Or am I mis-remembering that? I thought they were almost like the PSB M4u phones.
 
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amirm

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@amirm
I appreciate the "crapshoot" measuring bass response, but are you finding most headphones have this wide FR differential between left and right channel?
No, no. If you randomly place the headphone on the fixture, you will get large variations. But I am able to dial out 90% of that with ease with headphones with lager cups. So far, these NADs have been the worst in this regard. Just touch them and response changes massively. I am talking 10 dB up and down.

We will have to see how common this problem is as I keep testing more headphones. So far I am hopeful that it is not a big barrier. Even there, I had no trouble coming up with good equalization so using some intuition and judgement helps.
 
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amirm

amirm

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I thought this phone was one of the first to be designed with the Harman headphone research in mind. Or am I mis-remembering that?
I think the "room feel" thing just nets out to more bass. So in some sense it is compliant with Harman research of needing bass gain that speakers and rooms provide. But for the rest, it clearly is not following that.
 

LightninBoy

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#15
I thought this phone was one of the first to be designed with the Harman headphone research in mind. Or am I mis-remembering that? I thought they were almost like the PSB M4u phones.
You are correct. "Room Feel" was the (goofy) marketing name given to following the harman target curve.

With the left and the right FR being completely different, plus this result being quite different than other measurement on record, I'm not sure if we can read much into this FR. I used the oratory EQ settings as a baseline and got very good results and those are based on much different FR measurements that tracked close the the harman curve. I'll try amir's eq later and report back.
 
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LightninBoy

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No, no. If you randomly place the headphone on the fixture, you will get large variations. But I am able to dial out 90% of that with ease with headphones with lager cups. So far, these NADs have been the worst in this regard. Just touch them and response changes massively. I am talking 10 dB up and down.
This was a common complaint with those who reviewed and measured these.
 

xykreinov

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@amirm, since the fit and consistency of channel balance was a crapshoot- based on your listening impressions, what is more accurate in telling the headphone's overall response, the left or right channel measurement? The right channel seems to conform to the Harman target a decent amount more, and the averaged response doesn't resemble the right channel very much. Still, the right channel shared the most prominent issues with the left channel you found EQ improved, like lessened upper mids.
 
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