We’re back again with another earphone from the titan of Chi-Fi, Knowledge Zenith. The KZ ZS4 is a hybrid model with 1 balanced armature and 1 dynamic driver. I’m just going to come right out and say it: Coming in at under $20 the KZ ZS4 firmly and undeniably puts its foot down as the best earphone in its class. Read on to find out why.
Excellent design and fit
Has above average noise isolation
KZ’s best ever cable
Great clarity and an energetic full-bodied sound
Bass can be a little too aggressive
Earphone sensitivity: 101dB/mW
Frequency range: 20-40000Hz
Pin Type: 0.75mm
Cable Length: 120±5cm
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.
Package and Accessories
In typical KZ style, the ZS4 comes in very simple packaging with only the most rudimentary accessories. The earphones come in a white box with a nice, clear image of the product on the front.
Opening it up reveals the IEMs in a black plastic insert with some KZ branding embossed at the bottom. The accessories are, of course, placed underneath the tray. So, what’s in the box?
1x KZ ZS4 earphones
1x 2-pin cable
3x pairs of silicone Starline eartips (S, M, L)
User guide and warranty
Build Quality and Design
Available in red or black, the ZS4 sports the same shell design as the previous ZS3 model. It looks very much like a custom in-ear monitor and it has a similar fit and feel to a CIEM.
On the faceplates are Left and Right labels while the inner side of the shell says ‘Hybrid Technology’. I’m not sure why but several of these budget hybrids like to remind us of the fact that they are indeed hybrids. Most likely because it’s a big part of their marketing appeal as it sounds quite impressive to the uninitiated.
The plastic housings are extremely lightweight but they feel solid and well-built. So far as I can tell there are no vents in the shell but I don’t feel any pressure buildup as a result.
There is a solid ridge on the nozzle to hold your eartips securely and there’s a protective mesh covering the end of the nozzle to keep and ear wax and other nasty things.
The included 0.75mm 2-pin cable was a big surprise this time around. After just reviewing the AS10, I expected this would have an inferior cable but in fact, it’s just the opposite. The cable included with the ZS4 is by far the best I’ve seen with any KZ earphone.
It’s a braided black rubberized affair that is smooth, supple, not sticky, tangle-resistant with no kinks and it has very minimal microphonics (cable noise).
Yes, it does have that memory wire that KZ seems obsessed with but it seems to work quite well this time around. The same chunky Y-split is in place a couple of inches lower than it needs to be but it does have good strain reliefs.
The cable terminates with a rubberized L-shaped 3.5mm plug. Overall this is a fantastic cable and I hope to see it adopted broadly across other KZ models.
Comfort and Noise Isolation
The housings are moulded to conform naturally to the shape of the ear and in my case, the fit is exquisite. Needless to say, I can wear these for hours on end easily. KZ really nailed the physical design of these housings.
Due to the custom in-ear styled housings, the earphones fill a good majority of the outer ears and conchae. As a result, the ZS4’s noise isolation is well above average. Take these anywhere, you won’t hear anything and nobody else will hear what you’re listening to.
Gear used for testing includes Shanling M0 and Acoustic Research AR-M20 for the DAPs. I also tested with the FiiO BTR3 Bluetooth receiver paired with my Android phone. And for the desktop, it was Tidal HiFi from my PC in conjunction with the Topping DX7 DAC.
It’s super easy to drive and should work fine straight out of any phone or low-powered DAP and doesn’t require additional amplification.
The KZ ZS4 has a clear, vibrant and energetic sound with a punchy bass and lively treble. It has a V-shaped signature but the midrange still has plenty of presence and isn’t overly recessed.
mids are not recessed and good clarity intelligibility
The ZS4 has an enthusiastic and punchy bass. It is a boosted bass but I think it’s also pretty decent for such an inexpensive IEM. It doesn’t feel heavy nor bloated and has plenty of speed too.
Sub-bass reaches deep and can generate some proper rumble in your ears. It’s tuned for fun though and can get boisterous but just like the mid-bass performs better than you might expect.
The ZS4’s bass is suitable across multiple genres and seems right at home playing EDM or hip-hop just as much as a slow jazz tune like Eyolf Dale’s “Furet” although in bass-heavy tracks it does have some significant bleed into the mids.
There’s great clarity in the ZS4’s midrange along with good body and timbre. Wind up “I’m Leavin’ U” from Bootsy Collins’ Fresh Outta “P” University and we find the female vocals have more zest than Bootsy’s mellow crooning but it’s still pleasant overall.
The midrange can sound a bit recessed in bass-heavy tracks and the lower range suffers a bit while the upper mids remain clear and vibrant. When the bass is lighter you can fully appreciate the ZS4’s solid midrange.
Highs are crisp, lively and for the most part, easy on the ears. They give the ZS4 an open characteristic but on occasion can lean towards bright. There isn’t any noticeable sibilance or stridency. The treble imparts good detail in the music and is light and airy enough to counterbalance the boosted bass.
The ZS4’s stage has good width and an average depth. It can be quite track dependent in terms of size conveyed. At times it seems rather large but if the bass kicks in hard things become a lot more intimate.
KZ ZS4 vs bboooll BOT1 ($29 US)
The BOT1 has similar sub-bass reach but has a much tighter and leaner mid-bass. It has more punch and less thump than the ZS4. The ZS4’s midrange has more body and sounds warmer but can sound more congested in bass-heavy tracks.
The ZS4 has more lower and upper treble which gives it a brighter tonality. The BOT1 is more neutral in the upper mids and treble but doesn’t have the same liveliness or sparkle.
They’re both very comfortable but the ZS4 takes things to another level with it’s custom style shape and fit. In terms of accessories, they’re both basic but the BOT1 does provide an additional drawstring pouch and shirt clip.
KZ ZS4 vs Auglamour F200 ($20 US)
The F200 is less V-shaped and has a smoother overall presentation. Its bass is more textured and less pronounced and sub-bass doesn’t have quite the same impact as the ZS4.
The mids are very smooth and more linear on the F200 while the ZS4 has greater clarity and detail. Looking at the treble, the ZS4 has significantly more energy and quantity but the F200 is a lot smoother up top.
When it comes to build quality, there’s still nothing that can match the F200. Although the actual fit and ergonomics of the ZS4 is superior, the F200 is solid as a rock with its metal earpieces. The F200 has more accessories to offer too, adding silicone ear hooks, a shirt clip and a zipper case.
This one doesn’t even need any consideration. At this ridiculous price, you should just buy one or even several KZ ZS4 right now. I’ve already seen it on sale for as low as $12. So basically for the price of lunch or a couple of coffees you can get a great sounding earphone that will give you pleasure for months or years to come.