Disclaimer: The ZS12 was given to me by KeepHiFi in exchange for a review. They can be purchased for $60 here.
The ZS12 Pro 2 follows the very well-received ZS12 Pro X [Which, despite its name, was the first in its lineage.] The Pro 2 improves some things about the Pro X, and generally, is tuned more to my tastes.
The ZS12, as the name implies, is a 1+5 hybrid: 1 “flagship-grade super linear” 10mm Dynamic driver with 5 Balanced Armature drivers for midrange and treble.
Accessories: 2/5: Essentials only.
~Bog-standard KZ white box package with the exceedingly ugly lamp-wire-style clear 3.5mm cable [although a slightly more exciting USB-C cable option is available.] I don’t consider the KZ stock cables to be that great as far as sound quality, so I never use them. Besides, I always use 4.4mm cables anyway. For my rating, I used the ISN S8 cable, but I switched later to the XINHS 089 Black Dragon cable
~Standard set of KZ starline tips. They’re fine for some sets, but I’m using ivipQ V15 tips [which I’m 90% certain are a clone of some other brand?]
The KZ ZAX shells (right) seem identical to the ZS12 Pro 2 (left)
Shell design and fit: 3.5/5: Average, and a downgrade from the ZS12 Pro X. But comfortable.
~Gone are the full metal shells of the Pro 2’s parent. You get the normal clear resin housing, and a cheap plastic faceplate that appears to be vented. The faceplate looks good from a distance, but it’s honestly very cheap-looking up close.
~The good thing about the plastic shells is they are a lot lighter, and are less fatiguing to wear for a long time, unlike the Pro X. Also, I tend to enjoy clear shells that allow you to see the drivers inside.
~The nozzles are brass, and seem better-designed than the Pro X’s, and are just about the right width and length. The nozzles seem to be about 6mm wide.
~The Pro 2 does not have any tuning switches. This is not necessarily a con, since the ones on the Pro X mainly adjusted the bass, and it was only reasonably to have them all in the bass-up settings.
~The cable connectors are, of course, QDC [or “C-pin” as KZ calls them.] I find no issue with using regular 2-pin cables with any C-pin IEM, and have NEVER had one break.
Sound Impressions: 4.75/5: Almost perfect for the budget, especially for treble-lovers.
~The ZS12 Pro 2 improves the bass response over the Pro X, and the treble is nice, but doesn’t mask sibilance on songs.
Bass: 5/5: Elastic and deep-diving.
~The Pro 2 has proper punch and slam, and doesn’t sound stifled or restrained like on the Pro X.
~I feel like the bass is about the perfect amount. It’s enough to sound fun, but not enough to sound overwhelming. Even quiet or subtle bass lines in songs are not hidden or nearly inaudible, like on some sets that have quieter bass. This is a feature I REALLY appreciate. I still want to hear the bass, even if it’s a quiet section.
~Sub-bass dives all the way down to your core, with smoothness and ease. There is absolutely no sense of the sub-bass being rolled-off, which is my preference.
~Mid-bass is equally snappy and elastic. It has punch, moderate heft, but is not overly warm or thick. It does not bleed into the midrange. Even subtle bass bumps are accurately played, and not weakly overshadowed by the other frequencies.
Mids and Vocals: 4/5: Clean and capable.
~So, the midrange here is crisp, clean, and capable of detail delivery even while under audio duress. It’s not the best midrange I’ve ever heard, but for a budget set, it’s very good.
~The midrange tonality leans toward clean and clinical, but has just enough warmth to not sound totally sterile. If you’re looking for lush, immersive, and richly layered midrange, you won’t find that here.
~The details, instrument separation, and note incision are all very good for the price bracket, and it does what I want it to do. If the ZS12 had better-quality BA drivers, I’m sure the midrange would sound more organic and refined, however. I think just a hint more warmth and musicality would further improve the ZS12.
~Vocals are similarly clean and detailed. They are not the most emotive vocals I’ve ever heard, because the ZS12 leans toward details rather than musicality. Sibilant vocals, unfortunately, still show up with sibilance on the Pro 2, although it’s not ear-piercing like on older KZ sets.
~Vocals are staged “normally,” as in, they are not overly forward, not dramatically staged, or not recessed. They seem to accurately reflect the music. I wouldn’t mind a bit more richness to the vocals, however.
Treble: 4.5/5: Crisply extended and detailed.
~The ZS12’s treble is crisp, clean, and exhibits a pleasing level of note incision without sounding too dry or harsh. [Apart from not totally masking vocal sibilance.]
~Treble extension is very good, although don’t expect miracles at this price point. For most tracks, it has plenty of air and sparkle.
~Tonality is on point… No odd spikes or sizzle in the treble to alter the sounds of the instruments. But know that the treble air is elevated, and some might perceive that as being overly bright.
~Note incision is quite good… crisp, accurate note edges bring the spine shivers and excitement that good music is designed to give.
Soundstage: 4/5: Open scene, but not orbital.
~The soundstage here is decent for the price. It doesn’t sound congested or cramped.
~The stage is open and free, with decent left to right stereo separation, but not the widest I’ve ever heard.
COMPARISONS:
VS KZ Vader Pro: Tie verging on LOSE.
3DD, $29
~Vader Pro has more versatility due to the 4 tuning switches.
~Vader Pro has better build quality and similar comfort.
~Vader Pro sounds more dynamic and exciting, with even greater capability for note incision.
~ZS12 Pro 2 is a little brighter in the treble, at least compared to my current Vader Pro switch settings: UDDD
~Vader Pro has a grander soundstage.
~ZS12’s vocals are a little more forward and intimate, and at times, even fuller.
~ZS12’s mid-bass is a tad more bouncy, in a good way, than the Vader Pro. And overall, the tuning of the ZS12 seems more of a V-shape than the Vader Pro’s.
Both are very good value for money, but I think the Vader Pro would be appealing to more people, due the tuning options, and slightly more organic sound. [And the CCA Trio would be even more appealing to those wanting a warmer sound.] This is realistically a tie bordering on a win for the Vader Pro.
VS KZ Decet: LOSE.
$37, 5DD
~The Decet competes surprisingly well with the ZS12 Pro 2. The soundstage is more spacious and better-composed on the Decet.
~ZS12 has far crisper treble, but the Decet sounds more natural, and it doesn’t really sound rolled off!
~Vocals are smoother and lusher on the Decet.
~The Decet is bassier, but the ZS12’s bass is perfectly fine for my preferences. However, the Decet sounds beefier and richer because of it.
~If the 3DD Vader Pro barely beat the ZS12, the 5DD Decet wins handily. Its just incredibly capable and bombastic and spacious.
VS CCZ CZ10 TianGong: Tie verging on WIN.
1DD 4BA, $60
~TianGong has a far better build quality, but is also a lot heavier.
~CZ10 has a more vivid and exciting sound overall.
~The tonality is richer and fuller than the ZS12. The lower mids, specifically, are a bit warmer, which helps enrich the tonality.
~ZS12’s bass is bouncier and has greater sub-bass authority. And somehow, it’s also cleaner and crisper. I really appreciate the ZS12’s bass, and it’s a major deciding factor in rating it higher. However, the CZ10’s bass is also very good.
~The ZS12 has a clearer, more open soundstage.
~Honestly these two sets are both amazing budget hybrids. The CZ10 might appeal to more people with its more balanced, vivid tuning, but the ZS12 Pro 2 has a lot of things that appeal to my preferences. I rated the ZS12 higher in my test playlist [91 vs 88], so I gotta give it to the ZS12 Pro 2!
VS CCA HM20: Tie verging on WIN.
$60, 1DD 7BA.
~HM20 has a smaller shell that’s VASTLY more comfortable than most IEMs I own. I cannot FATHOM why KZ, CCA, and more companies don’t keep building on that small form factor design. I can hardly believe there’s 8 drivers crammed in each side.
~Vocals might be slightly more forward on the HM20, and slightly dryer.
~Instruments have a little more note weight and stage on the HM20. It’s actually incredible. I think this is a case where more BA drivers equals better detail.
~HM20 has a grander soundstage, but not by much.
~ZS12 sounds a little more refined in the treble… maybe a bit less BA timbre… HM20’s treble is spicier for sure. This is most evident in vocals.
~Honestly, it’s a tough call here. The ZS12’s BA treble is a little more refined, but the HM20 has wonderful separation and soundstage.
VS Simgot EW300: TIE!
$70, 1DD, 1PL, 1PZT.
The EW300 is small, light, and comfortable despite being an all-metal shell.
~It comes with 2 tuning nozzles for a bit of sound tuning options.
~The EW300 is a little more organic in the bass through lower mids region, but the ZS12 has more intense sub-bass.
~The ZS12 sounds a little more detailed and lively in the treble. The EW300 sounds more refined in this respect. Sibilance is also less of an issue with the EW300.
~So, I think the tuning of the ZS12 is more my style, but the EW300 sounds more refined. I call it a tie.
VS KZ ZAX: LOSE!
$65, 1DD, 7BA.
~The ZAX is a legendary KZ set that yet to be truly surpassed by newer KZ/CCA sets. However, the ZS12 Pro 2 comes close, I think.
~ZAX is far easier to drive, and requires low gain on my K7.
~ZS12 Pro 2 has slightly spicier, clearer treble. The ZAX is a tad warmer, and vocals male vocals have more body to them. The ZAX seems to have a more reasonable level of treble extension.
~Bass seems quite similar so far. ZS12 might be a little tighter in the bass. The ZAX has a little more mid-bass quantity, but it’s not a huge difference, honestly.
~Overall, because the lower mids on the ZAX are more full-bodied, the ZAX takes the lead here, but not by much. The upper mids and treble on the ZS12 are more nuanced and forward, which is better for some music.
VS TRN Shell: LOSE
$60, 3DD, 1PL
~The Shell is a much heavier IEM as it has an all-metal shell.
~The Shell has tuning nozzles to slightly modify the sound.
~The Shell has a much lusher and more immersive soundscape.
~The ZS12 has a more reference, clean sound, with cleaner bass. Note edges are snappier.
~Shell’s treble, despite being handled by a micro-planar, is smoother and more refined.
~Shell’s vocals sound more lifelike.
~I’m sure some will prefer the cleaner sound of the ZS12, but I slightly prefer the immersive, colored sound of the Shell, because it’s not just warm…it’s warm but with excellent treble detail and extension. The Shell is a very high bar to pass in the budget segment, and the ZS12 Pro 2 isn’t QUITE up to the challenge, although one could argue they’re just two different tuning styles but equally competent.
VS Pula PA02: WIN!
$189, 1DD, 4BA
~The PA02 has slightly more recessed mids than the ZS12, I think. Vocals are more forward and also smoother on the ZS12.
~The PA02 is a bit less bassy than the ZS12, and the sound is slightly cleaner and crisper in the midrange.
~Sub-bass is deeper on the ZS12. The PA02 is definitely more for treble-heads.
~The treble extension is even brighter and more detailed on the PA02.
~While the PA02 is a very competent set that deserves the fame and hype it’s gotten, the treble is a bit too edgy for 2025, and the bass loses whole-handedly to the ZS12, so I gotta give the win here to the KZ!
VS: Kiwi Ears Astral: WIN! [If you prefer the ZS12’s tuning.]
$299, 1DD, 6BA
~The bass on the ZS12 is cleaner. In fact, the overall sound of the ZS12 is cleaner, if edging toward dry at times compared to the Astral. I much prefer the bass of the ZS12.
~The Astral sounds beefier, warmer, and smoother.
~Treble on the Astral is detailed and extended, but not as crispy as on the PA02 or ZS12.
~Vocals are slightly richer on the Astral. The midrange is rich and melodic yet spacious. I think the Astral wins in this aspect, at least on most songs.
~While the Astral is very good at its goal of providing smooth, premium sound with warm bass, it’s simply not my usual preferred sound signature. It got rated 87/100, and the ZS12, 89/100. And this A-B test confirms that the ZS12 is more my style, even though the quality of the sound isn’t ALWAYS better than the Astral. Those who enjoy warm, organic sound, will greatly prefer the Astral, so take its “loss” here with a grain of salt!
VS: Sound Rhyme SR5S: LOSE.
$150, 1DD, 4BA
~SR5S’ treble is far more refined and talented than the ZS12. The ZS12 can get sibilant where the SR5S doesn’t.
~SR5S’ mid-bass has more impact and slam. The bass just sounds better overall. However, the sub-bass on the ZS12 is actually a little more authoritative.
~SR5S has richer, more melodic midrange. Vocals are richer and more natural.
~The ZS12’s treble is crispier and possibly more detailed.
~The SR5 and SR5S are some of the VERY best hybrids ever created, in my opinion, and it’s no surprise that no KZ hybrid has come close to competing with them!
The KZ ZS12 Pro 2 is yet another incremental upgrade to the KZ hybrid lineup. It hits a LOT of my preferences, mainly with the clear treble and deep sub-bass. Is it perfect? Not really, but it’s better than the Pro X. Do I wish it had slightly smoother treble that masks sibilance a little better? Yes. That’s really my only complaint with the IEM. It’s not as sibilant as the ZS10 Pro 2 and the ZSX Pro, so it’s a small improvement, I guess.
Should you buy this? I mean there’s plenty of better sets, including better KZ sets. If you want unapologetically crisp and clear treble with ample, punchy bass, for a budget price, the ZS12 Pro 2 might be what you’re looking for!