This is a review, listening tests, EQ and detailed measurements of the Nan-7 open-back planar magnetic headphone. It is on kind loan from a member and costs US $940.
The headphone is quite comfortable to wear. Alas, it doesn't feel well to touch. All those stats and edges of just about everything is sharp. This made an already difficult job of swapping pads even more annoying (see below). The adjustment of the headband is the worst I have seen with major difficulty trying to raise or lower the cups. Company needs to really pay attention to deburring and general smoothing of machined/cut parts.
I was also not a fan of the balanced XLR cable as it is very stiff and heavy. A more manageable 4.4mm cable comes with it as well. You are provided no less than three sets of pads. The largest ones were on it and they did not fit quite well in the case insert, showing a crease.
Testing was performed on GRAS 45-CA measurement fixture.
Nan-7 Headphone Measurement
As usual we start with our frequency response measurement and comparison against our preference target:
Wow, what is going on here? We have those relative large jaggies but also a ton of noise. I could filter the latter out by smoothing to 1/6th octave but I shouldn't have to. Measurements were so odd that I doubted my fixture so I measured two other headphones and neither showed any of the noise or variations. Suspecting that thick and somewhat inflexible pad may be responsible for transmitting resonances, I went though the pain of swapping the pads to the thinnest ones (shown in the review picture) and got this:
While no panacea, we see fair bit of reduction in response noise, pointing the arrow at the design of the headphone. I forgot to measure distortion with thinner pads so let's go back to default thick pads:
Sharp peaks indicate resonances and we see plenty of that at higher amplitudes. Bass distortion is also high for a planar magnetic headphone:
Group delay was the worst I have seen, indicating many sound sources mixing:
Compared the Nan-6 headphone, company aimed to increase sensitivity and that, they have accomplished:
We are talking thee times lower voltage to achieve the same level of loudness. But perhaps during that optimization, the rest of the design was compromised.
Impedance is flat and punishingly low 15 ohm. That is also nearly 1/3 the impedance of Nan-6. So better have a high-current source to drive it.
By this time, I was going to close the review and not even listen to the headphone as there were clear regressions relative to Nan-6. Having a sore arm after taking two shots in the same arm did not help either. Still, I thought I do a quick listen.
Nan-7 Headphone Listening Tests and Equalization
It took all of 10 seconds to realize the sound of this headphone is much better than casual impression of the measurements. There was impressive and deep bass response, balancing the rest of the response tonally speaking. This was with the thin pad as noted. So I thought I see if I can improve with EQ and indeed I did:
I started with Band1. Not only did that bring female vocals forward as the should be, it also significantly improved their clarity. Without it, their voices were somewhat gritty in addition to being recessed. We could stop there and call it done but I also put in the other two filters. The little filter at 600Hz seemed to improve clarity a bit and 80 Hz pushed even more bass. Once there, I was quite happy listening to Nan-7. The jagged and noisy frequency response errors were almost forgotten. Spatial quality was near top of the class adding great enjoyment in tracks that so benefit from it such as Youngstown by Steve Strauss:
Combine all this with the comfort that the headphone brings, a good time was had listening to track after track.
Conclusions
There is no question that objectively the Nan-7 has a number of design flaws that jump out in measurements. Fortunately our hearing has rather poor frequency discrimination and what is seen in the measurements is not what we hear. Headphone already comes with 90% of the bass response that we like to see (unlike Nan-6) and the bit shortfall in lower treble can easily be fixed with EQ -- at least with the thinner pads. I am not a fan of the tactile feel of the headphone but while you are wearing it, it naturally is not an issue.
The objective flaws combine with rather high cost stops me from personally recommending the Nan-7. However with the bit of EQ, great enjoyment can be had so I can't fault you for buy it.
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