Arriving in standard KZ packaging, initial inspection finds a rather nice included SPC cable, it’s unlike any of the stock braided brown/silver KZ cables we’ve seen before, the cabling below the Y split is flattish, making these tangle and knot resistant. The thinner cabling above the Y split has a sorta rifling texture to it that also makes it tangle and knot resistant, I’ve only seen this type of cabling on some of my Sony earphones.
These arrive with a set of these thin white tips that I couldn’t get a very good seal with so I opted for some silicone tips I had lying around. Regarding sources I found these synergized particularly well with the CX-PRO CX31993 dongle.
Starting with the bass, it peaks at around 70hz, it’s more midbass than sub-bass giving it the feeling of having good speed. sub-bass is somewhat rolled as you can see from the graph, these are no VE BIE. The bass isn’t hugely impactful, it’s quick and light on the feet, low frequencies have a good texture to them, good in quality just not the most potent in quantity.
Mids are in the form of a 2k Pinna and a 5k peak in standard KZ fashion, this particular iteration sounds very good in my listening, female vocals aren’t sibilant or harsh on the ears on high volumes, it doesn’t sound veiled like the singer is speaking behind a curtain, male vocals are much the same tale, listening to Sinatra and Jobin the vocals sound crisp and never muddy up the sound. Very satisfactory.
Treble is truly the star the show here, on the frequency graph we see a series of peaks starting from 8k and descending all the way to 20khz, suggesting a sparkly sound. The treble part of the frequency response is unlike any BA or DD I’ve ever graphed. The treble sounds crisp, very nicely detailed, not veiled in the slightest and not bright and exaggerated like ZSN PRO treble. instrument clarity is superb. The treble to me doesn’t get irritating or piercing, but the peaks around 10k do give the NRA a slight sibilant emphasis, though I do not consider these sibilant.
Soundstage is at times holographic, a quality rarely encountered in Chifi. With CX-PRO the soundstage is so convincing at times it has me looking over my shoulders. This is seriously good stuff, I have a newfound love for this magnetostatic fidelity.
Imaging is impressive, instruments can be pointed out around you.
Soundstage is wider than it is tall, and more behind you than in front of you. Mids and bass sound as though they come from inside your head and treble instruments sound just the right distance away and a little behind you.
Peeking inside the housing we’re met with a rather sizable DD, it is the first “triple magnetic” DD I’ve seen. The DD fires into a small vented cavity, airflow then goes through a small port hidden on the faceplate.
The magnetostatic driver directly faces the DD and fires into the same vented cavity, the cavity has a tube that leads to the nozzle.
Magnetostatic drivers are unusual, they are different from electrostats as they do not use a high voltage step-up transformer and they have only two leads, positive and negative, whereas an electrostatic has a third wire for DC biasing. A magnetostatic driver is made of two copper coils that are both facing a ferrous metal plate, The coils and plate are sandwiched between fixed magnets, for much the same reason why DD coils are surrounded by magnets. When you play music through the coils the magnetic pulses are generated to move the metal plate, generating sound. These drivers are physically incapable of reproducing low frequencies, every implementation of magnetostatic driver I’ve seen are paired with a DD to supply low-end. These drivers work the exact same way an electret microphone works, only the principal is reversed.
VALUE I just want to mention that these are the most affordable magnetostatic earphones to ever exist. Some other earphones I know to use this type of driver include the Shuoer Tape and Singer, BGVP Zero and the Senfer MT300. The Singer, MT300, and Zero are all far from excellent according to reviews I’ve seen, and Tape Pro was a huge letdown according to most impressions I’ve seen. NRA is SIGNIFICANTLY cheaper than competitors, and they sound delightful.
MT300 (1/DD 1/BA 1/MAG) $165
This is my other magnetostatic earphone, the MT300 low end is more sub-bass than mid-bass, it sounds thick and impactful whereas the NRA bass sounds faster and thinner. Mids on the MT300 are not on the level of NRA, the lower mids are recessed and the upper mids are unnaturally boosted on the MT300, NRA is much more harmonious, the MT300 has brighter treble that is very much fatiguing without foam tips, the treble extension is also worse on the MT300 despite having the additional benefit of a Knowles BA driver.
KZ DQ6 (3/DD) $22
Another offering from KZ. Pricing is about the same as NRA. Soundwise, the DQ6 is quite similar to NRA, the notable differences being a touch less low-end on the DQ6 and treble that is sibilant and rolled off after 10k. The mids and upper mids sound very similar between the two. if you loved the DQ6, these will sound familiar and better.
This is my current favourite earphone, the best all-rounder in my collection. Compared to NRA, HE01 has a more low-frequency extension. Speed and texture are similar between the two. Mids are better on the HE01 as the HE01 doesn’t have the slight sibilant emphasis that the NRA has, so vocals sound cleaner and more pleasing on HE01. When it comes to treble, HE01 sound a little airier, though for literally a fourth of the cost the NRA is basically neck and neck with HE01 in terms of fidelity and raw details.
Overall, I find it very hard to not recommend the NRA, twenty-some dollars get you exotic driver technology and truly impressive sound.