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:
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:
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:
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:
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:
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:
Group delay is somewhat instructive here, showing discontinuities where we have some frequency response variations:
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:
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:
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:
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/
I like the modern look of the headphone:
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:
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:
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:
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:
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:
Group delay is somewhat instructive here, showing discontinuities where we have some frequency response variations:
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:
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:
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:
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/
to take the clamp pressure off. Hidden gem is right!
