KZ ZST & ZSR IEMS…Real Good Sound, Real Cheap!

Update: The ZST and ZSR are still great earphones for the money, but the new ZSN is even better…better tonal balance, and more refined sound…check out my comments on my other post, Best Affordable/Budget Audiophile Headphones (2019)!

As an unabashed audio junkie, I’m always in online audiophile groups chatting about the next big audio thing. As I surfed, I began to hear more and more about IEMs from a Chinese company called KZ, which stands for Knowledge Zenith. Everyone talked about their new hybrid IEMs equipped with dynamic drivers then paired with one, two, even three balanced armature drivers, all selling for under $50!

Not only that, people were saying that they actually sounded good!

Well being the skeptic that I am, I assumed this was pure bargain-hunting budget audiophile hyperbole. I figured we were firmly in “good for the money” territory, and when we’re talking about a triple-driver hybrid IEM (2 Balanced Armature, 1 Dynamic), for under $30, that’s not too high of a bar to leap. Not to mention that this is a company that doesn’t even have a proper website. At least not an English one. All they have is a couple of facebook pages scattered around, and a few official stores here and there. 

But I kept seeing post after post about these amazing products selling for ridiculous prices. Even the major tech websites like CNET and Wired were talking about their cheapest single-driver IEM, the ATE, which sells for about $14, calling it the best cheap earphone out there.

These IEMs are so cheap that people are collecting them. They are buying all of the different models in all different colors and comparing the sound of each. They are also carrying different models for different types of music, for example, using a more neutral sounding model for acoustic music, and then pulling out a more bass-heavy model to rock out with. At these prices, there are so many possibilities.

After reading so much about them, curiosity finally killed the cat, and I bought three models from Amazon. I purchased the ATE, the single dynamic driver model that started everyone talking about KZ, and then two of their hybrid driver models, the ZST, which has 1 dynamic and 1 BA driver, and the ZSR which has 1 dynamic and 2 BA drivers, all with the optional mic/play/pause controller on the cable.  Since the “entry level” ATE has been talked about ad infinitum and is priced very close to the hybrid models which I feel offer more for your money, I’m mainly talking about the ZST and ZSR in this post.

It’s not about features:

First of all, if you buy these earphones expecting a whole lot of accessories in the box, then you will be disappointed because there’s not much that comes with them. You get the left and right earpieces, usually a detachable cable with 2 pin connector, (except with the ATE) and a few silicone or foam ear tips. That’s it. But then again, that’s not what these things are all about. It’s about the sound. But I’ll get to that in a minute.

As far as accessories are concerned, if you want a case, or additional ear tips, or an upgraded cable, you can buy it separately. I actually like this, because it allows me to try out a particular model, and if l like it, then I can add a little bit more money and dress it up. You can even buy a separate Bluetooth cable and make your IEM’s wireless. The best part is all these extras are priced just as reasonably as the earphones themselves.

What comes in the box….

Build Quality:

I have read a few Amazon Reviews talking about some of these KZ products failing (earpieces falling apart), but in my personal experience, they seem to be pretty sturdy. The earpieces are made of very hard plastics, and the strain relief along with the memory wire on the cables seem to be designed well.

As far as fit, it was a mixed bag, with the ZSR fitting pretty much like a glove right out of the box with the supplied tips, while the ZST was more of a challenge. The ZSR has a longer nozzle for the ear tips than the ZST, and the ZST constantly popped out of my ear until I switched out the stock tips for some of Comply’s universal-fit comfort foam tips. After switching the fit was great.

Sound Quality:

Once you achieve a good seal in your ear, the sound from both of these models is remarkable, yet different. The ZST with its one dynamic and one balanced armature driver per side has more of a balanced sound profile with a slight emphasis in the treble. It sounds really great with Jazz, Vocal and Acoustic music, but it has enough bass oomph to handle pretty much any genre.

The ZSR with its two balanced armatures and one dynamic driver has more of a V-shaped sound with an emphasis on the bass and treble, it matches really well with electronica and hip-hop. I would consider neither one of them to be flat, but the ZST is closer to neutral than the ZSR. The ZSR is definitely warmer with a bit more of a bass boost, but the bass is not out of control, it’s just elevated with quite a bit of detail to it.

Because I prefer a warmer sounding headphone for my everyday carry, I use the ZSR a little bit more, and I think it’s a pretty good earphone for all around listening even though the bass can distract a little bit when listening to songs where the bass isn’t supposed to be accentuated. At home when it’s quiet and I’m listening to some mellow jazz or jazz vocal music, I appreciate the closer to neutral sound of the ZST.

Since I spoke so much about the bottom end of these IEM’s I also want to touch on the treble for a moment. I hear many people talk about the treble on KZ earphones causing sibilance on certain tracks, and while I tend to agree with this, I found that it bothered me very little. I did listen to a few songs with very hot cymbals or horns that caused me to turn down the volume a little bit, but this was more with the ZST than the ZSR, and it happened just a few times over a few weeks. So if you are very sensitive to treble, this is something to keep in mind.

In comparison with the 1More Triple Driver In-Ear, which I have called the best budget earphone out there, I found that the 1More had a more balanced sound than either KZ product, along with a more vivid midrange, but they weren’t as open or detailed.  Both KZ earphones also imaged a lot better. Highs on the 1More are nowhere near as forward as on the KZ IEMs, so that makes them sound dark in comparison. I usually like a more mid-centric sound sig, with a sight bass bump and slightly rolled off highs, but I also like an open sound, so the warmth and openness of the KZ earphones won me over in the end.

ZSR Close Up…


At $20 for the ZST and $30 for the ZSR, these earphones represent a huge value proposition for IEMs and not just budget ones. The open, warm, detailed sound of both these models, especially the ZSR, should please all but the most snobbish audiophile. While they are not as detailed or transparent as some earphones costing hundreds of dollars, the sound gets you a good part of the way there for under $30! That is remarkable.

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