The S2 is their new truly wireless offering from Knowledge Zenith, it features a single dynamic and single balanced armature design with bluetooth 5.0 support. 

The KZ S2 was provided to me by Linsoul in exchange for a review.

In the box

  • IEMs
  • Charging case
  • USB-C Cable
  • Instruction
  • Extra tips

Build quality and accessories

I’ll talk about the build from the price perspective. As of this moment, the S2 are about 29$ on Indiegogo. For that amount of money, the build is adequate, earbuds feel good, there are no sharp edges and the joints are smooth. 

The case hinge is a bit loose and may come undone on itself if shaken. The USB port being at the bottom of the case makes it quite awkward to charge having the earbuds in. 

The tips selections are basically 2 times the same set, which was too small for me and I had to go for aftermarket tips, not all of those work either because if they are too long the case wouldn’t close. 

Fit and comfort

Fit seems to be really dependent on ear size, for me with slightly bigger ears the fit was a bit loose and would mainly rely on the buds to be held by the tips, on the other hand for my girlfriend the buds will fit snugly and sit in place without issues.



I feel like an elephant in the room has to be addressed before talking about sound. The totally wireless IEMs to me need to have good usability, otherwise, it makes no sense to pick them over wired ones taken their drawbacks in terms of fidelity, having to charge the battery etc.

In general terms, the S2 passes the usability test for me. The range is good, and the signal is stable so the IEMs don’t really randomly disconnect. Track navigation and controls even though could be a bit more sensitive work well once you get used to them. The microphone is only acceptable, in a noisy environment I wouldn’t expect to be able to have a phone call with the S2 but otherwise it shouldn’t be a problem. 

I wish there was a way to control the volume directly from the earbuds, I feel this is too often neglected in the TWS IEMs, I also wish the charging was faster to be able to quickly top up the IEMs just before a workout or other activity. 


The S2 is a V-shaped IEM, leaning more towards the brighter side of things. The extension both ends is good enough, it doesn’t quite reach the deep subbass nor does it hit the highest treble that well but it doesn’t feel like there’s a big chunk of music missing. Technically it does get a bit congested with busier tracks but it definitely holds it’s own in its price category. Similar to some other KZ models it does have a tendency to pick up sibilance which can be an issue depending on your music preferences. There’s also a bit of background noise hissing.


I can recommend the S2, especially given the initial price on Indiegogo, it is, obviously a budget set but it ticks a lot of boxes for not much money. I’m sure most people would be happy with them as a beater or workout set as long as they can get a good fit.

Get the S2 here:

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