Review: KZ S2 – The Best TWS Under $50


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KZ S2 is a multi-driver true wireless earbud (TWS) that has sound quality that punches way above its price range.

General Usage
Rank #26
Audiophile Usage
Rank #5
Tested with Sparrow System 1.0

Score Breakdown

Click the label to navigate to the section.






What We Like 😍
  • 18hrs playback time
  • “High Performance” mode to dramatically reduce audio/video sync issue
  • Great sound quality for its price range
  • Seamless transition from mono usage to dual usage
  • Comfortable to wear
  • IPX5 – Great for a sweaty workout
  • Stable Bluetooth connection
What We Don't Like 🤢
  • USB-C charging port at the bottom of the case
  • Slow earbuds charging time
  • Mic has audible noise pickup
  • Slightly loose fit
  • Only one pair of ear tips provided and they are the same size as the stock tips

Where To Buy

The KZ S2 is available on Indiegogo for $29.


After the release (and the quick withdrawal) of the KZ T1, I have been looking forward to KZ’s next iteration of the true wireless earbuds. KZ obviously knows how to create a budget earbuds with quality sound but their product line has been bugged by inconsistent build quality and inane user experience.

So how does the KZ S2 fare?

Let’s find out.

KZ S2 and its packaging
KZ S2 and its packaging



  • Playtime: 10hrs
  • Connector: USB-C
  • Wireless Charging: No

With the bulky case, I was expecting the battery life to be longer. In hindsight, I should have known from its light weight. However, it still clocks in an impressive 10 hours playtime.

Comparison of charging case: Jabra 75t (L), KZ S2 (M), Samsung Galaxy Buds (R)
Comparison of charging case: Jabra 75t (L), KZ S2 (M), Samsung Galaxy Buds (R)

The case uses USB-C jack for its charging connector which is really convenient for my work setup.

I uses Macbook Pro for my laptop and Samsung S10 for mobile. All of them support USB-C charging and data transfer.

Although there is no wireless charging capability, it was no surprise for me. It would be asking too much for the manufacturer to squeeze in this feature at such a budget price range.


The case cover can be easily lifted with one finger. I find the magnetic grip on the earbuds to be slightly on the weaker end. The earbuds could be flick out with a good hard shake with an open cover.

The only light indicator on the case.
The only light indicator on the case. “Green” light indicates that the case has at least 70% – 100% worth of battery left.
There is a button on the back of the case that when pressed, triggers the light indicator to light up. The light indicator does not light up automatically when you lift the case cover.
There is a button on the back of the case that when pressed, triggers the light indicator to light up. Note: The light indicator does not light up automatically when you lift the case cover.

The case has no external light indicator. The light indicator is located inside the case where you need to lift the cover. The light indicator is a single LED light that shows different colors like red, yellow and green to reflect battery and charging status.

A weird position for the charging connector
A weird position for the charging connector

The charging port is situated at the bottom of the case. That is bad UX for me. The case is lying awkwardly flat on its side while it is in charging mode. The earbuds are still retrievable at this state but it takes extra work to lift the case up before taking out the earbuds.


The look of the case has the stereotypical “chi-fi” tws look – black matte surface with rounded corners.

The plastic smooth texture of the case doesn’t feel premium and when you carry it on your palm, it feels really light and “hollow”. 

The build quality is decent but you can definitely see and feel it is more on the budget end. When you shake the case, you can hear the earbuds rattling in the case.


  • Weight (without earbuds): 55g (44g)
  • Volume: 6cm X 4.2cm X 3.1cm = ~78.12 cm cu (~4.7672 in cu)

At 55g, the case is considered light. Removing the earbuds shaves off another 10g from it. However, the case takes up a bit of space at 78 cm cu. It protrudes evidently when you keep it into your jeans pocket.

An upside to the rounded smooth case is that you can easily slide it into your pocket with no obstruction.



The battery on the earbuds can last 4hrs on single charge. The charging speed for the earbuds is slow, clocking at 30mins playtime with 15 mins of charging. That is the slowest among the TWS that I have tested.


  • Control Mechanism: Touch
  • No volume control
  • Triple tap for “High Performance Mode” which decrease the lag time for audio/video sync
  • Seamless transition from mono to dual

You control the KZ S2 via touch/tap. I prefer tactile controls (like those you see on Jabra 65t) over touch controls because I just haven’t seen anyone execute the touch controls well. It was either too sensitive or not sensitive at all. The touch controls on the KZ S2 did not impress me much either.

The KZ S2 earbuds
The KZ S2 earbuds

The hit rate is passable. On average, the earbuds register 8 out of 10 of my touches. The issue is the delay feedback. It takes around a second for the action to take place after you tap the controls.

The KZ S2 allows all the usual controls like playback, call controls and activation of voice assistant.

There are no volume control on the earbuds.

High Performance Mode

There is an interesting mode call the “High Performance Mode”. It is activated by triple-tapping either side of the earbuds. A voice feedback will echo “High Performance Mode” when it activated. You can switch it off by doing the same action and the voice feedback will echo “Standard Mode”.

According to the manual, the high performance mode helps with audio-video latency especially for streaming videos and gaming. It supposed to mitigate the lag time problem that is common with Bluetooth wireless connection.

I tested the “High Performance Mode” with the latency test on Youtube.

In “Standard Mode”, there is a lag time that is visible to me. It is not very off but enough for me to discern. Once I switched over to “High Performance Mode”, the latency issue was hugely improved to the point where I’m satisfied with it. Pretty impressive.

I will haunt the supplier to dig out more info on why this mode is not on by default. My guess is that the battery will be consumed quicker with the mode on.
Update: The supplier has replied and she confirmed that “High Performance Mode” will increases the consumption rate of the battery.

Seamless transition from mono to dual

I dig the switching experience of mono usage back to dual earbuds usage. It is one of the better experiences I had with TWS. Most TWS will require you to put the current earbuds back into the case and then take them out to resume dual usage. But not the KZ S2. You just have to take the remaining earbud out of the case and it will auto-connect back to current earbud that you are using.

Kudos to the Bluetooth SoC – Realtek 8763 chip that they used.


The length of the S2’s nozzle is short and not intrusive. It fits comfortably in the ear canal. The earbuds weigh 5g each and it rests well on the ear without exerting additional pressure on it.

The short nozzle of the KZ S2
The short nozzle of the KZ S2

The earbuds have a higher profile and it slightly sticks out of the ear. Combined with the ear tips that they provided, it felt a little loose on the ear. An additional pair of ear tips were provided but it was the same size as the pair on the earbuds.

Wearing KZ S2 in ear
Wearing the KZ S2. Its slightly high profile and small ear tips lead to a loose fit for me.

The body of the earbuds is mainly made from glossy plastic. The faceplate where the touch sensor is situated has a matte plastic surface. The earbuds feel well put together and the overall design of the earbuds has more curves than the KZ T1. However, I wish they have added some colorway to the S2, other than the overall black look, to give it more character.

Driver configuration label on the earbuds
Driver configuration label on the earbuds

Strangely, KZ chose to print the driver configuration on the earbuds which looks kinda tacky to me.


In the press release, it was stated that the S2 has a CVC Noise Isolating Microphone. From the mic test conducted, we can hear the background sound is still being picked up quite audibly.

But luckily the voice clarity is pretty decent. It wasn’t clear as day but you can separate the voice through the noise that it picked up.

You can check out the mic test below:



Overall, I really the sound of the KZ S2. It is definitely punching well above its price range. The bass is strong without overwhelming the mids. The mids are not recessed nor forward. Lower mids sounded rich and have good body. The upper mids are, however, a little dry for my taste. The treble performs with good energy and not rolled off. You get a good amount of sparkle without sounding overly-bright.

KZ S2 in the case
KZ S2 in the case


The sub-bass reproduction is decently present. You can feel the rumble in songs like Why so serious? (from 3:25) by Hans Zimmer.

The bass itself has a good amount of impact and quantity. Songs that are bass-heavy like Help by Borgore sounds really enjoyable on the KZ S2. On certain tracks with complex layering (Harder, Better, Faster, Stronger by Daft Punk), I do feel like the bass tends to stand out a bit much.


Despite the strong bass, the mids do not sound recessed nor is it too forward. This is not surprising given the multi-driver setup.

Female vocals are under control without sounding shrieky. I do find that the lower mids have a better body and appearance compared to the upper mids which sound a tad dry for me.


The treble sounded great to me. The wild electronic violin distortion in Rude by Daniel Jang is well-controlled and yet not dulled-down. The top end has good energy and does sparkle without being overly bright.


  • Bluetooth Version: 5.0
  • Multi-point Connection: No
  • Supported Audio Codec: SBC, AAC
  • Bluetooth Audio SoC: Realtek 8763

Once connected to my Samsung S10, the Bluetooth connection defaulted to AAC.

The pairing with my phone was smooth with no hiccups or surprises. Just find “KZ S2” and you can pair right away. Nothing fancy like the Cambridge Melomania 1.

The connection is quite stable, with the dropouts being rather infrequent, probably once every hour of usage.


  • IPX Rating: IPX5

The KZ S2 has an IPX rating of IPX5. It is sweat-proof and suitable for workouts. I brought it for a quick run but I found that the fit could -be tighter. It felt a little loose on the ears when I was running with it.

A larger ear tips would have given a better fit but unfortunately, KZ only provided one set of ear tips that are of similar size to the stock tips. It is a little poor on the accessories side, even for a budget TWS.

💬 Conversation: 7 comments

    1. Can use either one solo… However do note that some controls will not be available e.g. next song /previous song is achieved by double touch on right / left earpiece; haven’t tested if the corresponding control works in solo mode. My unit is older, with indicator light on inside of unit and no button outside, but all in all loving my unit

  1. Buyer beware! The quality of this product is poor. I supported the Indiegogo campaign for these earphones and was excited to receive them. When I did, one of them was defective and would not charge or switch on at all. I returned them to the manufacturer in China at the cheapest possible shipping method ($17), but the manufacturer would only reimburse $5 of the shipping cost because that is what it cost them to dispatch from China in the first place. So I got poor quality goods and paid $12 for the privilege.

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