Introduction & Disclaimer

Many thanks to KEEPHIFI for sending me a sample to review.
This is my 4th KZ IEM, and as far as I know, originally the most expensive one I’ve tried so far.
Originally around 100 EUR, it can now be had for around 50 EUR at KEEPHIFI, and sometimes a little less on other platforms.

More product info can be found here (non affiliate link) -

https://keephifi.com/products/kz-za...aming-noise-cancelling?variant=41232410476590

Build, Design & Ergonomics

The first thing I want to point out is that KZ is finally nailing down the ergonomics.
Previously, I’ve tried the ATE, ZS10 and HBB PR2, none of which fit my ears properly.

The ZA12’s plastic shells are very similar in aesthetic quality to the HBB PR2, which means that at a distance, fit and finish are more than acceptable, although I’m not a big fan of the repeating jewel facade and viewed up close the internals are somewhat untidy with visible glue marks and bubbles.

Looking closer inside the shells, we can see 6 drivers per side.
This is where things start to look a bit weird to me.
Directly inside the 5.5mm plastic nozzles you can find a single BA driver, and almost sealing the entire nozzle opening is the single larger dynamic driver.
Then if you look really carefully, there is a tiny vent that reaches through, past the two drivers to the cluster of the small dynamic and 3 BA drivers.
I’m not an expert in IEM tuning, but from what I’ve seen and heard, I don’t really approve of this driver placement and tuning method.
More on that later.

The same old KZ cable is provided which feels weird for an IEM that was originally priced at just under 100 Euros which can be found on KeepHifi for 50 Euros, or even a bit less on other platforms.
The cable is very prone to tangling, and is more difficult than average to put on, but it can be easily replaced and it does the job.

At the top of the shells are four tuning switches.
The two left switches boost bass and the two right switches control midrange and treble.
There is a provided key for toggling these switches.

Provided in the package are 3 sizes of silicone tips and the classic hard foam KZ tips, but like usual no carry case or bag, which would have been a shockingly poor performance at 100 Euros, is more of a disappointment at 50 and an inconvenience at the lowest price.

The Sound

I no longer have the ZS10 and HBB PR2 to compare this with, but from memory, I feel like KZ is still stuck in this tuning-zone of pumping out as much splashy treble and pinna-gain as possible.
The ZA12 has probably the most refined midrange that I’ve heard from them so far, exhibiting very competent resolution, but with an over-blown upper midrange and low treble that just sounds grating and splashy.

(miniDSP EARS exaggerates most treble measurements on IEMS, so ignore the 10dB peak)

KZ ZS12 PRO X

Listening to the Live MTV version of Hotel California, the very first guitar strum sounds too metallic with an extra ‘sheen’ that is unnaturally present, mostly for the lack of bass.
Overall the actual balance from midrange to treble isn’t a janky roller-coaster – it actually sounds mostly ‘correct’, just not balanced with the lower mids and bass.
I’m mostly reminded of very old electrostatic, electret and piezoelectric headphones with lightning fast transients, high treble detail but a total lack of bass.

By comparison the long discontinued KZ ATE actually sounds more balanced, with a more authoritative bass response and a reigned in treble which together gives a more balanced sound that is unfortunately also affected badly by some very strong pinna-gain.

So what about the tuning switches?
The two on the right are useless. The ZA12 is already tuned extremely bright, so why anyone would want to boost it further is completely beyond me.
Boosting the bass to the maximum yields an increase of about 3dB at 20hz and 2dB at 60hz.
This does almost nothing. It doesn’t even begin to bring the bass in balance with the entire midrange.

In order to get this closer to a balanced or the meta tuning, serious EQ’ing must be performed.

Through my Fosi Audio SK01, I crank up the bass to about 2 o’clock, which should add roughly 5dB of bass shelf, which does a lot but the boosted bass comes out boomier and loses texture. Still though that’s not enough; to really get these close to where I want them, I need to bring down the treble to about 11 o’clock reducing treble by about 2dB, but I still think the upper mids could use some taming.

While performing manual tone-sweeps, there is an obvious peak at around 3.6Khz, and a big peak from around 8.5-12KHz.

After some quick adjustments, it’s clear that it’s not just the tuning that’s letting it down.
Going back to what I was saying about driver placement and tuning, stuffing the nozzle with two drivers has made imaging quite narrow, albeit somewhat accurate and the soundstage very tiny.
I would definitely not recommend these for gaming, but music also doesn’t spread outwards from left to right anywhere near as well as some others, even at lower prices.

Comparisons

(KZ ZA12 is in GREEN) KZ ATE Despite the lower resolution, the long discontinued KZ ATE offers a more balanced and overall more cohesive sound.
CCZ Harmony BC01 Pro Again much cheaper and lower resolution, the BC01 Pro has superb ergonomics, an awesome bass response and fantastic imaging that makes it a far more enjoyable overall package.
BLON BL03II Products like this make me wonder why KZ is still even in business. These sound incredible for the price. Actually to be fair, the BLON’s ergonomics are even worse for me than the KZ and the cable is also very easily tangled, so it’s not perfect either.

Final Thoughts

This all makes me wonder if KZ is still even relevant any more.
Unless they start producing consistently bassier IEMs without pinna-gain and splashy treble, they will quickly become, if not already, a niche brand, or at worst irrelevant.

Maybe the brand is for treble or detail-heads, or maybe there are those out there who really appreciate this kind of presentation.

I don’t know, but what I do know is that it’s just not for me and as far as I’m concerned, the bar is so much higher today than it was when KZ first started pumping out endless models.