The KZ ZST is the latest addition to Knowledge Zenith’s ZS range and is the brand’s first attempt at producing hybrid in-ear-monitors (IEM). It was released not long after the ZS3 and is available in faux carbon fiber and dual-color designs — great if you’re looking for IEMs that stand out from the crowd. The ZST is also available with or without a microphone.
The ZST isn’t just a pretty pair of IEMs, it sounds incredibly good too. This all boils down to its hybrid design which makes use of a dynamic drive and balanced armature. All other KZ models before this feature dynamic drive designs which produces sound by pushing air using a diaphragm and coil. The ZST makes use of both a dynamic drive and a balanced armature which produces sound using a resonating coil and magnets.
- Design: In-ear with or without built-in microphone and answer button
- Driver Unit: Dynamic Driver / Balanced Armature hybrid design
- Frequency response: 20Hz-20000Hz
- Sensitivity: 120 dB
- Impedance: 18 ohms
- Cable: 1.2m detachable
- Earbuds: 3 sets
- Input Jack: 3.5mm stereo
- Weight: 18g
Hybrid IEMs can be a bit tricky to design since they use two different technologies. However, when done properly, hybrids offer the best of both worlds — punchy bass and less detailed rumble is produced by the dynamic drive (DD) while the balanced armature (BA) handles frequencies with finer details. A well-designed hybrid can deliver compelling bass and low frequencies while maintaining the finer micro details that typically get lost in many DD IEMs.
KZ has done a great job with the ZST’s hybrid design. It delivers amazing audio performance that can rival branded hybrid IEMs in the $60 range. The first time I put on my ZST I was amazed at the clarity of its treble and sweet rumble of its bass. It clearly had the two extremes balanced nicely.
Though bass and low frequencies are not delivered with quite the same punch as on the ZS3, they’re still pretty good. Due to the presence of a BA, the ZST can sometimes sound a bit harsh on the high frequencies — a problem I rarely experienced with the ZS3. Overall the audio signature on the ZST has a slight V shape compared to the more pronounced V on the ZS3, making the ZST sound warmer and livelier with less rumble in the lows.
I have been using my ZST for several months now and must say that I’m very impressed with its audio quality. My ZST has been used almost exclusively with my Android smartphone and so far it has performed quite well although I believe the audio output from a smartphone doesn’t quite unleash its full potential.
In fact, some audiophiles who have reviewed ZSTs suggest using an audio source with sufficient power such as the FiiO X5 to bring out the best in them. It seems the ZST loses some punch on the lower frequencies when plugged into less powerful audio sources such as smartphones or notebooks. Providing the ZST with enough power will bring the lower frequencies (100Hz or lower) to life.
Build Quality and Comfort
The ZST features over-the-earlobe cables and they do a reasonably good job at securing the IEMs to your ears though not as secure as the ZS3. Comfort-wise, the ZST is slightly less comfortable than the ZS3 although I think this mostly depends on the shape and size of your ears.
The ZST also features detachable cables and the cables are transparent so you can actually see what’s inside — a cool feature if you want something that looks different from the usual black cables that come with other IEMs.
With its transparent blue and purple casings and transparent cables, the ZST doesn’t have the appearance of a $20 IEM. In fact, it actually looks like something that costs four times more from big name brands such as Sony and Sennheiser. I must say that Knowledge Zenith has done a wonderful job with the ZST’s aesthetics.
The KZ ZST is available for $17 at Banggood. Click here for more details on how to get yours.