It has been a while since the KZ overlords have blessed us with some new budget goodies but we have a new one here today. In this review, we’re checking out KZ ZST X. The ZST X is a hybrid dual-driver IEM with 1 DD and 1BA. It’s the successor to the KZ ZST which was the first KZ hybrid, and one that turned out to be a huge success for the company. It was one of the earliest truly budget-priced hybrid earphones on the market and it sounded pretty good too. Can this X variant improve upon the original? Only one way to find out!
Disclaimer: This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.
KZ ZST X
- Comfort, noise isolation
- Good build quality for the price
- Like the ZST but better
- SPC upgrade cable
- Value for money
- Treble might be bright for some
Package and Accessories
The packaging is standard budget KZ and consists of just a simple little white box with the KZ logo on the front. Inside are the earphones, detachable cable and 3 pairs of silicone eartips.
Build Quality and Design
The ZST X shell is mostly unchanged since the original ZST. It’s currently available in 3 colours: black, cyan and purple. The shells are acrylic and pseudo-custom in shape. VST X is printed in large typeface on the faceplate in silver colour.
Just like the previous version, the ZST X is a dual-driver hybrid with one 10mm dynamic driver and one balanced armature driver. It has 0.75mm 2-pin connectors similar to other KZ models. Overall the build quality feels good for an earphone at this price point.
In terms of comfort, the ZST X is great and fits naturally in my ears. I can wear these earphones easily for hours at a time without experiencing any discomfort or hot spots. Noise isolation is decent and about average for this type of shell.
The KZ masters have decided to bless us with an upgraded high-purity silver-plated cable. Although it shares some of the shortcomings of the old brown cable (like no chin slider), it handles better and in my opinion, looks a lot nicer too.
At the top are the opaque 2-pin connector housings followed by pre-formed ear guides. The Y-split and right-angled 3.5mm plug share the same opaque appearance as the connector housings making the design look cohesive. It’s a pretty decent cable, to be honest, especially considering the sub $20 price of the earphones.
Gear used for testing:
- FiiO M6
- Shanling M0
- iPhone -> Shanling UP4
- Windows 10 laptop -> Cozoy TAKT C
The KZ ZST X has a very lively V-shaped sound with good detail retrieval. It has boosted bass and treble levels but the vocals are not overly recessed and are a definite improvement in that regard compared to the original ZST. It has a fun tuning but one that still impresses when it comes under scrutiny.
The bass is punchy and thick but still reasonably fast. This isn’t a basshead IEM but having said that, I think it could still satisfy people looking for a potent low end. ZST X can bring the rumble in its sub-bass too and has enough juice to make your brain wobble.
Listening to Twista’s “Wetter”, the ZST X surprised with the way it was able to deliver those heavy bass notes but at the same time keep the vocals clear and engaging. On this track, the vocals usually sound like they’re in the background to some extent but this little KZ kept them engaging and they never sounded obliterated by the bass.
This is where I think the ZST X shows the most notable improvement compared to the original model. The mids here are more forward, more naturally weighted and have improved instrument separation.
In Oh Hiroshima’s “In Solar”, the various guitars, strings and vocals are all easily distinguishable, even with all the busy kick drums and incessant crash cymbals going on. That’s really saying something for an ultra-affordable V-shaped IEM.
The treble is another area that has clearly improved since the original ZST. With this updated X variant, the treble is more even and shakes off the dryness of its predecessor. But the treble focus can still cause fatigue on occasion. One example is in Tool’s “Invincible”, where the slam of the drums sounds a little too sharp in its attack.
The soundstage is fairly intimate but has good spatial cues and stereo imaging. Vocals have good placement, neither too near or too far away from the listener. The stage width and depth are only average but thanks to some admirable separation it never sounds confined or heavily congested.
KBEAR KS2 ($24)
The KBEAR KS2 (review here) has slightly more bass texture and speed. KS2 sounds more evenly balanced and doesn’t have an as aggressive treble accent like the ZST X. However, ZST X is a detail monster and can pick up micro-details that others in its class cannot.
I think that the ZST X is actually very competitive compared to the KS2 and people might choose either one based on their personal tonality preference as they’re comparable in a technical sense.
CVJ CSA ($20)
The CVJ CSA (review here) was a surprising entry from a brand I hadn’t been familiar with prior to that review. It has a warmer and fuller sound than the ZST X which might not be as initially exciting but sounds more linear and laid back. Where I might occasionally feel the need to take a break from listening to the more aggressive ZST X, the CSA is one I can listen to for even longer periods of time.
I have to admit, I wasn’t expecting the KZ ZST X to be as big an improvement over the original as it is. It’s an earphone that performs extremely well in the context of its low price and direct competitors.
In addition to sounding better than it should, it’s got good build quality, is very comfortable and comes with KZ’s upgraded SPC cable. I can see this one being another huge success for KZ and bringing the masters one step closer to global domination. Recommended!
- Impedance: 12Ω
- Earphone sensitivity: 107dB/mW
- Frequency range: 20-40000Hz
- Pin Type:0.75mm
- Line Length: 125±5cm
- Driver configuration: 1 DD + 1 BA