The Nuraphone have a unique hybrid design and only turn on via skin conductivity once on your head. These features posed quite a few challenges when measuring these headphones with our HMS, which means our results for sound, isolation and leakage are not quite a 1:1 when compared to our subjective impressions of the headset. Below are some of the challenges we faced and how we went about solving some of these problems.
Keeping the headphones powered on: Due to their skin conductivity feature, the Nuraphone would not stay powered on when on our dummy head which lacked the necessary conductivity to make it work. We had to use copper conductive tape, which we then wired to a metal fan. When placed on the tape, the headphones would stay on.
Personalization process: Now that we had the headphones powered on, we needed to complete the personalization process using our HMS. This requires the headphones to have a good seal, which is detected when doing the first listening tests via their app. The app was telling us that the seal wasn’t proper enough and we couldn’t run the personalization process. We then decided to add elastic bands until the app recognized the headphones to have a good enough seal.
Unfortunately, it took us 4 bands to achieve a good seal. This resulted in the cups being squished, modifying the form of the headphones, which we think could have affected the results. The increased pressure may not be reflective of a typical use case which adds a bit of error in our sound, Noise isolation and leakage measurements. We also don’t know if the personalization algorithm works with dummy heads as it might require a proper human inner ear and eardrums.
Microphone not detected by our testing PC rig: We had to create a new methodology to test the headphones using a phone. We installed a Digital Audio workstation on our test phone and measured the mic that way. This means while not directly comparable to our mic measurements of other headsets, they shouldn’t be too different since they are still using the same Bluetooth wireless connection.
We couldn’t test these headphones as standard over-ears.
Due to their unique design with in-ear tips inside the over-ear cups, we couldn’t use human measurements with the Nuraphone. We usually use in-ear microphones to measure how over-ears perform on different human test subjects in the bass range. Due to the tips, we couldn’t perform those tests. And with those tests missing, we couldn’t process the results as over-ears. This is why we used our in-ear curve in our Nuraphone review.
What we did when we saw the results weren’t matching what we were hearing:
We decided to write this review with a more subjective approach when it comes to the sound of the Nuraphone. A handful of us compared it with the Bose QC 35 II and gave their general impressions by listening to a few different tracks. We tried different songs to be sure to get a good impression for the bass, mid and treble ranges.
Lastly, we still chose to publish the review since after listening subjectively we realized that our final measurements were not that too far off. However, for the text we decided to write our subjective impressions instead of just interpreting the data for the relevant test boxes.
Overall this was one of the more challenging headphones we had to test and learned a lot from it. We hope to apply these lessons when measuring other headsets in the future and we also added some suggestions for a future testbench update.
Let us know if you have any suggestion or would have done things differently so that we can improve our testing procedures.