Our Verdict
Decent for neutral listening. They have a deep, powerful, and consistent bass on top of a good mid range. Unfortunately, their treble is a bit uneven and the mid-range is a bit recessed, pushing the vocals and lead instruments to the back of the mix. Overall, these headphones will be better suited for bass-heavy genres. However, the in-ear fit might not be ideal for long listening sessions.
- Durable design.
- Decent audio reproduction.
- The variant without an in-line remote is a bit limited.
- Slightly bulky earbuds.
- Uneven treble performance.
Mediocre for commuting. They don’t isolate lower-end noises like the deep rumble of a plane or bus engine. On the upside, you don’t have to manage battery life, but you might feel their wire is in your way sometimes. They are easy to carry around and will offer no delay if you watch video content during your commute.
- Durable design.
- Decent audio reproduction.
- The variant without an in-line remote is a bit limited.
- Slightly bulky earbuds.
- Uneven treble performance.
Decent for sports. These earbuds are very portable and won’t make you sweat more if you use them for sports. Their ear-hook design is very stable and will be adequate for sports, but this also means they won’t offer the freedom of a wireless design. You might find their cable gets in your way while exercising.
- Durable design.
- Decent audio reproduction.
- The variant without an in-line remote is a bit limited.
- Slightly bulky earbuds.
- Uneven treble performance.
Okay for the office. The in-ear fit might not be the best to wear for hours during a work day, but on the upside, they do a good job at blocking work environment noises. They also don’t leak much so you can listen at high volumes without disturbing your colleagues. You can also use them the whole day as you don’t need to monitor battery life.
- Durable design.
- Decent audio reproduction.
- The variant without an in-line remote is a bit limited.
- Slightly bulky earbuds.
- Uneven treble performance.
Poor for gaming. The model we tested doesn’t have a microphone, although there is a variant with one. Their sound is slightly boomy and their fit won’t be great for long gaming sessions. On the upside, their wired connection means you won’t have any latency issues.
- Durable design.
- Decent audio reproduction.
- The variant without an in-line remote is a bit limited.
- Slightly bulky earbuds.
- Uneven treble performance.
Changelog
- Updated Nov 15, 2021: Converted to Test Bench 1.5.
- Updated Mar 24, 2020: Converted to Test Bench 1.4.
- Updated Nov 21, 2019: Converted to Test Bench 1.3.1.
- Updated Nov 21, 2019: Converted to Test Bench 1.3.
Check Price
Popular Headphones Comparisons
The KZ ZST Hybrid are passable in-ears that set themselves apart by the value they offer. They are very affordable but feel slightly cheaper than the other headphones in the KZ lineup we’ve tested so far. Some may feel like they are overly sharp and don’t passively isolate noise as well as other KZ headphones. See our recommendations for the best noise cancelling earbuds, the best wired headphones, the best cheap earbuds, and the best earbuds under $50.
The KZ ZSN and KZ ZST are very similar headphones with slight differences. The ZSN feel a bit more high-end thanks to the metal-like backplate on their earbuds. Some may find them overly sharp, but both headphones have very similar sound profiles. That said, the treble of the ZSN is more uneven. Other than that, they are practically identical and your choice will rely on which headphones you think look the best.
The KZ ZS10 are better headphones than the KZ ZST. Their earbud casings feel better made and sturdier than the ZST’s. Also, their sound profile follows our target curve better and will sound noticeably better in the treble range. Overall, both headphones still have very similar sound quality. On the other hand, the ZST are more affordable and could offer a better overall value for most people.
The KZ AS10 will be a better option than the KZ ZST. Their overall build feels slightly better made than the ZST and their sound is more accurate for critical listening. Also, their fit is better at isolating noise, so they’ll also be more versatile if you want to use them for commuting. On the other hand, the KZ ZST are noticeably more affordable and offer great value.
The KZ ZST are better headphones than the Apple EarPods. The KZ sound is better, and they also feel noticeably sturdier. However, some will prefer the one-size-fits-all design of the Apple, which seem to be more comfortable than the in-ear fit of the KZ. Also, the Apple have an open design, so they don't block noise well and won't be a good option for commuting. On the upside, they have an in-line remote and microphone, which the KZ model we’ve tested is lacking, though there is a variant that has them.
We've upgraded our Headphones Test Bench to 2.0! This update brings several key changes to our tests and usages, making it easier than ever to interpret our sound results based on your personal preferences. You'll also find a brand-new interactive graph tool featuring multiple targets (including our own!) for you to explore and compare.
For a full breakdown, check out our changelog, which includes detailed commentary from our test designer explaining the rationale behind our update.
We'd also love to hear your thoughts: your feedback helps us keep improving, so join us in the comments!
Test Results
The KZ ZST are very similar in style to the other KZ headphones we’ve reviewed so far, but their overall build is smaller and feels a bit more plasticky than the rest. These headphones still look better than what their price tag suggests, thanks to their transparent casing that lets you see the electronic parts of the headphones. Their braided cable also adds to their premium feeling. They come in a few flashy and colorful designs, as well as a black and a carbon fiber designed one, to suit your preferred style.
The ZST are as comfortable as the other KZ models. They are very lightweight and their angled design fits nicely inside the ear without putting too much pressure. They are a bit bulkier than most in-ears, but their overall build is a bit smaller than other KZ headphones. On the upside, they also come with different tip options to help you find a better fit and air-tight seal.
These headphones do not have an in-line remote with controls. However, there is a model variant with a one-button control scheme on the in-line remote.
Like most in-ear headphones, the KZ ZST don’t trap much heat inside the user’s ears. While their design is a bit bulkier than most in-ears, you shouldn’t feel a big difference in temperature after wearing them for a while.
The KZ ZST headphones are very portable and will easily fit inside most pockets or in a bag. Their ear-hook design and the bulkier buds take up slightly more space than most in-ears, but you shouldn’t have any problems carrying them around. However, they don’t come with a pouch or a case to protect them.
The KZ ZST feel slightly cheaper-made than the other KZ headphones like the KZ ZS10, KZ AS10, or the KZ ZSN. There is a clear distinction between the backplate of the earbud and the earbud frame itself while other models feel like one solid unit. The plastic also feels fairly thinner and doesn't look like it would be able to survive the same amount of pressure before breaking as the other models. On the upside, even this very affordable option has a detachable and replaceable cable, which makes them more durable. You can also buy a Bluetooth adapter cable for these headphones to make them wireless.
Like most ear-hook designed headphones, the KZ ZST are stable, and you should be able to jog with these without any problem. They don’t move around in your ear and should be fine for most light sports. However, the cable might get stuck on something, yanking the headphones out of your ears or hurting you because of the ear-hook design.
Like most in-ears, the ZST have excellent frequency response consistency. If the user can achieve a proper seal using the assortment of tips, then they should be able to get a very consistent bass and treble delivery every time they use the headphones.
The bass of the KZ ZST is great. LFE (low-frequency extension) is at 14Hz, which is excellent. Low-bass follows our neutral target very well, meaning these headphones produce just the right amount of thump and rumble, which is common to bass-heavy music and sound effects. Mid-bass, responsible for the body of bass guitars and the punch of kick drums, is fairly flat and within a dB of our curve as well. High-bass, responsible for warmth, is overemphasized by more than 3dB, making the bass of these headphones a bit boomy and muddy.
The mid-range of the ZST is good. However, there is a broad 5dB recess centered around 800Hz. This pushes vocals and lead instruments towards the back of the mix by giving more emphasis to the bass and treble frequencies.
The ZST’s treble performance is okay. The response throughout the range is fairly uneven. The 4dB overemphasis in the low-treble will add too much detail and brightness to vocals and leads. On the other hand, the broad drip in mid-treble will make sibilants (S and T sounds) in those frequencies quite lacking in detail while the peak around 9-10kHz will make them overly sharp and piercing, especially on already bright tracks. However, not everybody experiences treble frequencies the same, so your listening experience may vary.
These headphones have excellent imaging. Their weighted group delay value is 0.18, which is very good. This results in a tight and fast bass and clear trebles. The L/R drivers of our test unit also showed very good matching, which helps with proper placement and localization of instruments and sound effects (like footsteps) in the stereo image. However, these results are only valid for our unit, and yours may perform differently.
The soundstage is poor. This is because creating an out-of-head and speaker-like soundstage is largely dependent on activating the resonances of the pinna (outer ear). The design of in-ears and earbuds is in such a way that fully bypasses the pinna and doesn't interact with it. Also, because these headphones have a closed-back enclosure, their soundstage won't be perceived to be as open as that of open-back earbuds like the Apple AirPods (2nd generation) Truly Wireless, or the Bose SoundSport Free.
The isolation performance of the KZ ZST is acceptable. In the bass range, where the rumble of airplane and bus engines sits, they achieved about 2dB of isolation, which is inadequate and won’t be great for public transit. In the mid-range, important for blocking out speech, they reduce outside noise by more than 15dB, which is good. In the treble range, occupied by sharp S and T sounds and A/C noise, they isolate by 31dB, which is quite good. The KZ ZS10 and KZ AS10 have a better isolation performance overall.
The leakage performance of the ZST is great. These in-ears do not leak in the bass and mid ranges, and their leakage is concentrated in a narrow range in the treble range. Therefore, their leakage will be thin and sharp-sounding. The overall level of the leakage is quiet too. With the music at 100dB SPL, the leakage at 1 foot away averages at 32dB SPL and peaks at 55dB SPL, which is just over the noise floor of an average office.
The ZST do not have a microphone and therefore, the recording quality has not been tested.
The ZST do not have a microphone and therefore, the recording quality has not been tested.
They are passive headphones that don’t have a battery. You can also buy a Bluetooth adapter cable for these headphones to make them wireless.
They do not have a compatible app or software support for added customization options.
These headphones are not Bluetooth compatible. However, you can buy a Bluetooth adapter cable for these headphones to make them wireless.
Thanks to their wired connection, you won’t have any latency issues and shouldn’t experience a delay when watching video content or gaming. If you buy a Bluetooth adapter, expect latency issues like most Bluetooth headphones.
These passive headphones provide audio over their 1/8” TRS connector on pretty much any platform that has the appropriate jack.