The KZ ZA12 was kindly provided free of charge in exchange for an honest review. I didn’t receive monetary or any other kind of compensation and I don’t use affiliate links. The price of the KZ ZA12 is $62 for the version with the tuning switches and the cable without a mic. Other buying options are also available. You can buy it from KeepHiFi.
KZ (Knowledge Zenith)
KZ (Knowledge Zenith) is a Chinese audio brand founded in 2012, known for producing affordable in-ear monitors (IEMs) with features like hybrid drivers and detachable cables. The brand is popular among budget-conscious audiophiles and has released many successful models that often rival more expensive offerings in sound quality. Some popular models are the KZ ZSN PRO X, the KZ DQ6 and the KZ AS10 Pro among many others.
KZ ZA12 earphones
The KZ ZA12 is a high-performance hybrid in-ear monitor that combines dual dynamic drivers with four balanced armature drivers. Inside you will find a 10mm super-linear dynamic driver unit in combination with a 8mm high-performance dynamic driver. An efficient balanced armature array is used for the high and ultra-high frequencies. The array comprises two 30019 BA drivers and one 31736 which is essentially a composite double BA unit. So the actual driver count is 5 per side and not 6 as advertised.
To tune or not to tune?
The KZ ZA12 is available in two versions; A version that supports custom tuning and the standard version that comes with the factory tuning.
The tuning version allows the user to enhance bass, midrange and treble frequencies to match their preferences. This version of the earphone is equipped with four micro switches that can be used to fine tune the frequency curve of the KZ ZA12.
The switch 1 increases the bass by 1dB while both switches 1 & 2 increase it by 2dB. The switch 3 increases the mid and high frequencies by 1dB while both switches 3 & 4 by 2dB. All switches ON, will increase the overall frequency response while other combinations are also supported. As an example you can increase the bass by 1dB and the mid/high frequencies by 2dB.
Cable and accessories
The KZ ZA12 supports a detachable cable system with 2-pin 0.75mm recessed plugs for enhanced durability and more secure connection. Yes, you have read it correctly, 0.75mm and not 0.78mm which is the standard norm so you will have to buy a specialized 0.75mm cable if you want to go balanced. A very strange decision from the part of KZ that excludes almost all aftermarket cable options.
The 1.2m long, silver-plated cable is made from two twisted branches and has a 3.5mm plug. It is an entry level cable with plastic plugs that is thin and lightweight. It doesn’t look especially durable but it doesn’t get tangled and has low friction noise. You have the option to order the cable with a multifunctional in-line control and a built-in microphone.
Except for the cable you also get three pairs of KZ branded silicone ear-tips, one pair of memory foam and a small metallic pin to adjust the tuning switches. Some more ear-tips and a small carrying pouch would have added more value to the overall package which at $62 is not that competitive by modern standards.
Design, wearing comfort and build quality
The ear-shells of the KZ ZA12 have a hybrid construction and are divided into two symmetrical parts, one metallic and another one from transparent resin material that allows a glimpse at the internals. A nice combination of two different textures that adds finesse and elegance to the outer appearance of the KZ ZA12. The faceplates feature a diamond-like pattern that shines in the light and is complemented with an outer edge that bears the KZ ZA12 logo in a decorative handwritten styling.
The KZ ZA12 ear-shells have a teardrop-like shape with an ergonomic inner surface and mildly extended sound nozzles while they are very lightweight. The fit is stable, comfortable and stress free making them ideal for prolonged use while they isolate pretty well. Build quality is very good, the outer surfaces are smoothly finished without blemishes and the two parts are firmly bonded together without visible gaps.
Efficiency
The impedance rating of the KZ ZA12 is 45Ω with 103dB of sensitivity so while it can be used from entry level portable sources, it does need some extra power to make it shine. For this review I have used the Violectric CHRONOS and the Chord Mojo as solid single-ended sources.
Listening impressions
The dynamic drivers of KZ ZA12 produce the so-called “driver flex” phenomena that makes a clicking sound when you press the earphones against your ears. However, this “driver flex” noise doesn’t affect the sound quality or produce audible distortion.
The stock tuning of the KZ ZA12 is a rather balanced one with not too emphasized bass, present mids and a touch of upper mid-range emphasis that extends right up to the treble without making it sound overly bright.
The sub-bass is adequately deep but it rolls off rather early and doesn’t have the quantity and the heft that are needed to produce pulsating bass for modern music. You can set the switch 1 to ON in order to slightly increase the amplitude of the sub-bass. The same effect is produced by the 1 & 2 switch combination but it also boosts the mid-bass.
With the switch 1 set to ON, the overall tonal balance of the low-end is good for all kinds of music. The mid-bass is gently prominent to make the sound warm and engaging with modern music or rock but still tonally correct for listening to classical. The bass line is clean and textured without any severe bloat or bleeding into the mid-range.
The KZ ZA12 can sound quite dynamic and impactful when needed but its bigger strengths are the control and the discipline of the bass. The technical behavior is rather amazing for the price point, the bass is fast, tight and controlled with impressive layering and definition for the category. The textures might not be that weighty and visceral but the KZ ZA12 is by no means a dry and lean sounding earphone. The KZ ZA12 is a real winner when it comes to the overall tonal balance and the technical performance of the low-end.
More listening impressions
The mid-range has a neutral and transparent quality to it, the tuning is mostly balanced with some upper mid-range prominence that is there to add energy and clarity without becoming too fatiguing. Voices and instruments are reproduced just as the mixing dictates without much intervention from the earphones. The KZ ZA12 can effectively capture the harmonic diversity of a recording and it plays the music with a rather natural timbre without much artificiality or BA timbre. The technical performance is very good for the category, the mid-range is clearly articulated and well defined without sounding thin or clinical.
The treble is quite bright and energetic with plenty of luminosity and sparkle. It resolves well and it doesn’t sound too sharp or piercing. Most people are going to like the extra clarity and the precise definition of the KZ ZA12 but some others may find the treble as little fatiguing on the long run. You can’t dial the treble down with the aid of switches but you can increase the bass to shift the presentation towards it. The textures are not particularly thin or dry and the timbre is not that metallic or artificial. The KZ ZA12 doesn’t break new ground but it sounds surprisingly cohesive and grain-free for the category.
The feeling of the soundstage is mostly flat and horizontal but it is airy and extended enough as not to sound congested. Imaging precision and positioning are average but still good to handle complex music passages without losing composure and definition.
In the end
The tuning version of the KZ ZA12 is a good sounding IEM with an overall sonic performance that can easily compete with other offerings in this price range. I would definitely avoid the stock version as it is bass light and you can’t fine tune it, for $4 extra the tuning version is a no brainer choice.
The KZ ZA12 is also a comfortable, lightweight and well made earphone but the overall package is not competitive and the 0.75mm cable interface is a major let down. Still, the KZ ZA12 is the only earphone with tuning switches at this price point, so it is a significantly more versatile option than similar products and it definitely deserves your attention.
Copyright – Petros Laskis 2025.
+ Pretty balanced tuning
+ Excellent bass technicalities for the category
+ Good clarity and transparency
+ Natural mid-range and crisp treble
+ Not too artificial or metallic timbre
+ Wide soundstage
+ Tuning version with four switches
+ Lightweight and comfortable with good isolation
+ Well made and beautiful looking
- Driver flex noise that doesn't affect music listening
- Some lack of sub-bass extension, especially in the standard version
- The treble can sound a little bright
- Flat soundstage with mediocre imaging
- Lackluster cable with 0.75mm pin interface
- Poor accessory package
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