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NAD Viso HP50 Review (headphone)

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amirm

amirm

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I'm surprised. Here's my *theory* on what's going on: the HP50s measure close to the harman curve in a controlled lab setting. But more than most headphones, getting that ideal placement and seal is tricky with the HP50s. Amir's measurement techniques (however he is doing the averaging) gets closer to the real world experience under typical usage and his simple EQ settings focus on the gross errors instead of micro corrections that may not be entirely accurate.
I think you are onto something. When I was measuring them, I indeed gave up on any optimal setting as the variations were out of control. So I decided to get an approximate sense and then verify through EQ. I then played with placement on my ears. With other headphones even though the measurements show variations, perceptually I hear very little. Not so with the HP50. Just slightest lift of the bottom would cause massive change in tonality and loss of bass. So likely many people are wearing these sub-optimally and any measurement that maximizes the response is likely not matching the perception as you posit.
 
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I don’t know if you already do so, but for sealed headphones I can recommend to “calibrate” the placement by using a a low frequency single tone (30 Hz or so) and move the headphone slightly until a peak value is reached. This can only be done one side at the time.
This was one of the *failed* procedures I tried a while back. Let's think about this. The two areas where measurements are difficult are in low frequencies and highs. Inversely, what is reliable is between around 100 Hz to 5 kHz. It reasons then that we attempt to get proper accuracy in this perceptually important region. What happens to deep bass at 30 Hz has to do with taste to some extent anyway.

The procedure that worked for me was a two point optimization. I start with 425 Hz which is the calibrated point for the reference curve I use. I attempt to both optimize and match the two channels. I think bounce down to 80 Hz. This frequency is low enough to represent the bass response but high enough to not be subject to dramatic variations due to fitment. Sometimes I have to go back and forth between these two points to optimize them. Once there (and combined with mechanics of how I mount the headphone), provides very good results so far. What is good about this is that it also avoids averaging which reduces resolution.
 

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So I have a question. Obviously the frequency response and distortion are two important things in sound quality with headphones. Headphones radiate into a small space, so there's no off axis to worry about. Also, they only have one driver per side, so there's no crossover.

What exactly do headphone makers do to make the headphone response as desired? Manufacturing many drivers and hoping their various resonances line up the right way in the enclosure? I'm just curious how you actually develop a product that has no way to adjust frequency response of the transducer as in a crossover or with dsp.
 

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Yo bossman. How long does the THD measurement take? I really really think it would be cool if you showed the same post-PEQ you apply.

As it stands, for something like 89 bucks, and such low THD even at 100+dB, this thing is amazing if it actually takes well to that EQ objectively.
 

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I've just done an EQ based on Amir's measurement, I traced the good measured channel using VirtuixCAD, the red line in the graph below and then used REW to EQ it to the Harman Curve.
1609980391795.png


And here's my EQ based on Amir's measurement:
NAD HP50 Amir.jpg


And here's my previous EQ based on Oratory's measurement:
NAD HP50 Oratory my own EQ.jpg


There is a tonal difference between the two EQ's even though they're done to the same Target Curve, it's because the measurements are different. The measurements share some similar features, but they're more emphasised in Amir's measurements, along with a unique lack of treble from 1-5kHz. I haven't compared them to my flat reference speakers yet to be sure which one is the most accurate, although I do have an impression of which one is most accurate. It was a joy to listen to my NAD HP50, I'd forgotten just how good they were! (They sound a lot more open than I remember, clearer sound than I remember, and the bass impressed me again....but still just as smooth as I remember).
 
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Yo bossman. How long does the THD measurement take? I really really think it would be cool if you showed the same post-PEQ you apply.
It is a completely different setup as far as wiring and measurements (post EQ one). Having done it now, I am not seeing anything revealing in it. Distortion goes up when boosted, and down when not. The improvement in tonality using EQ is so much that any distortion consequences -- within reason -- is an acceptable price. When it is not, then I will identify it.
 
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There is a tonal difference between the two EQ's even though they're done to the same Target Curve, it's because the measurements are different.
To be clear, I completely eyeball the EQ. I made no mathematical attempt to be precise. I open for fewest quick filters I can develop. So better matching mathematically can definitely be done than what I am doing.
 

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To be clear, I completely eyeball the EQ. I made no mathematical attempt to be precise. I open for fewest quick filters I can develop. So better matching mathematically can definitely be done than what I am doing.
Yep, I realised that! :D
 

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It is a completely different setup as far as wiring and measurements (post EQ one). Having done it now, I am not seeing anything revealing in it. Distortion goes up when boosted, and down when not. The improvement in tonality using EQ is so much that any distortion consequences -- within reason -- is an acceptable price. When it is not, then I will identify it.

When you said "having done it now" did you mean tested the headphone post-EQ for the distortion metrics? If so, any chance we could get a peek at what percentage difference in something like the bass region is? I'm awfully curious to see how much the percentage raises there. I literally have no clue how big the difference could be. In my head, it could be something like 5% or it could be something like 50% off something like a few dB's of EQ in that region for example.

I'm just super curious on the actual numbers. End-game curiousity would be to see if distortion climbs with a pattern. Like if two headphones measured similar distortion (like an HD6XX and one of it's brethren) if an equal boost would land one headphone at 10% THD at 20Hz for example, while the other skyrockets to something like 30%. Or if they would almost equally rise with distortion. And wondering if this behavior tracks with different headphones.
 
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When I was measuring them, I indeed gave up on any optimal setting as the variations were out of control. So I decided to get an approximate sense and then verify through EQ. I then played with placement on my ears. With other headphones even though the measurements show variations, perceptually I hear very little. Not so with the HP50. Just slightest lift of the bottom would cause massive change in tonality and loss of bass. So likely many people are wearing these sub-optimally and any measurement that maximizes the response is likely not matching the perception as you posit.

Do you have the ability to make many measurements and then average them out? I appreciate that nobody reviewing as much stuff as you would want to do that if they don't have to, but isn't that the better approach if any kind of 'touching' of the test rig yields different measurements? (hopefully any variations in measurements will average out to provide a 'typical' scenario).

Again, I completely 'get it' if you wouldn't want to do that when a headphone presents such behaviour under test.
 
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Do you have the ability to make many measurements and then average them out? I appreciate that nobody reviewing as much stuff as you would want to do that if they don't have to, but isn't that the better approach if any kind of 'touching' of the test rig yields different measurements? (hopefully any variations in measurements will average out to provide a 'typical' scenario).

Again, I completely 'get it' if you wouldn't want to do that when a headphone presents such behaviour under test.
If you read my other posts, you will see that I don't think averaging is the right strategy here. It reduces real resolution of the data and gives a false illusion of a consistent measurement. Best to use our eyes and intuition when dealing with interpreting the graph than creating a false representation through some kind of artificial averaging. In no way averaging with be a predictor of individual response.
 

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This was one of the *failed* procedures I tried a while back. Let's think about this. The two areas where measurements are difficult are in low frequencies and highs. Inversely, what is reliable is between around 100 Hz to 5 kHz. It reasons then that we attempt to get proper accuracy in this perceptually important region. What happens to deep bass at 30 Hz has to do with taste to some extent anyway.

The procedure that worked for me was a two point optimization. I start with 425 Hz which is the calibrated point for the reference curve I use. I attempt to both optimize and match the two channels. I think bounce down to 80 Hz. This frequency is low enough to represent the bass response but high enough to not be subject to dramatic variations due to fitment. Sometimes I have to go back and forth between these two points to optimize them. Once there (and combined with mechanics of how I mount the headphone), provides very good results so far. What is good about this is that it also avoids averaging which reduces resolution.

Thanks for clarifying @amirm . I guess 80 Hz could be just as useful since that is way lower than the typical headphone driver's Fs and therefore dependent on the seal.
But have you seen significant deviations between channels in the, say, 0.1 to 5 kHz region once the channels SPL have been "calibrated" using a <100 Hz single tone on your rig? If so this mismatch would likely occur when the headphone is used on a human head and thus reveal a less than optimal mechanical design. Or is that jumping to conclusions in your opinion?
 

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nad-electronics-viso-hp50-noise-isolating-over-ear-headphones.16811
10307361_thumb.jpg


The the flatter one on the left is the early version,the rounder one on the right is the later version.
That's weird, I bought mine last Summer and mine looks more like the one of the left in terms of overall headband shape, yet you say that one is the early version? The headphone on the right looks like someone has just taken the headphone on the left and bent it to a different shape....you can even see the crease marks in the leather where you can see it's been bent......are you sure they're not just the same model revision but the one on the right has had it's headband bent to shape by the user?
 

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I had those for couple years, but they started to loose their sound a bit by bit, and then one driver just went dead.
Tried to contact NAD, but never get any responce from them._
So i read from online, that drivers have these breaking issues and you actually cant listen them too loud or they break very easily.

It´s a sad sad thing.
 

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I had those for couple years, but they started to loose their sound a bit by bit, and then one driver just went dead.
Tried to contact NAD, but never get any responce from them._
So i read from online, that drivers have these breaking issues and you actually cant listen them too loud or they break very easily.

It´s a sad sad thing.

Its the same fault mine had. It probably is not the driver but the internal wiring in the headband.

are you sure they're not just the same model revision but the one on the right has had it's headband bent to shape by the user?

Look at reviews on the day of introduction. They all have the flat headband.
Look at the current NAD offerings. They all have the round headband.

It's a crappy design with poor fit issues and crappy internal and non replaceable headband cable.
 

Robbo99999

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Look at reviews on the day of introduction. They all have the flat headband.
Look at the current NAD offerings. They all have the round headband.
I think there is just the flat headband version, that pic you showed was just from some random dude on an internet forum:
https://www.head-fi.org/showcase/na...50-noise-isolating-over-ear-headphones.16811/
I think it's quite easy to see by the creases in the leather on the "round one" (the red headphone) that the headband has been bent to shape by a customer. I've done a quick google and can't really find pics from reviews supporting that there are two versions of this headphone, and the few pics I've found seem to suggest they've always been the more square overall headband shape. I also bought mine new last year so mine should be the latest revision you'd think. I think there's only ever been one version of this headphone, unless you can show me some compelling more verifiable links than the pic you posted earlier. But, it's not a big deal for sure, just if you've got the links to hand.

Here's a pic of mine (I did a "rubber anti headband resonance mod on it"), but pic for the purposes of showing the more square headband shape:
HP50 Headband Resonance Mod (b).jpg
 
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