KZ ZS6 (Review)

Written by Adrin S

When I first saw the new KZ ZS6 on pre-order sections at a few popular online stores, I immediately got excited. Here was a new set of IEMs in Knowledge Zenith’s Z series with a new model number so I assumed it must be something very different from earlier releases from KZ. But when I realized that the ZS6 appears to be nearly identical to the earlier ZS5 with some minor changes here and there, that excitement quickly died out. I assumed the ZS6 was just a marketing gimmick by Knowledge Zenith and that it was nothing more than just a lightly upgraded version of the ZS5.

Nevertheless, I still decided to give the ZS6 the benefit of the doubt and when GearBest offered to send a review sample I obliged. After all, Knowledge Zenith is a brand that has a reputation for surprising us with solid IEM’s in the past 1 year releasing, one after another, the ZS3 which was then followed by the ZST and ZS5. Each IEM in the Z-series offered their own distinctive characteristics and each had amazing audio performance so I was really curious to find out what exactly KZ had in store with the new ZS6.

Product Highlights
  • Design: In-ear with or without built-in microphone and answer button
  • Driver Unit: 2 Dynamic Drivers / 2 Balanced Armatures hybrid design
  • Housing: Aluminum with open design
  • Frequency response: 7Hz-40000Hz
  • Sensitivity: 105 dB
  • Impedance: 15 ohms
  • Cable: 1.2m detachable
  • Earbuds: 3 sets
  • Input Jack: 3.5mm stereo
  • Weight: 26g

When I first received my ZS6, it seemed like just any other Z-series IEM (In-Ear Monitor) from KZ. There are the ear pieces, detachable wires and 3 sets of ear buds in different sizes. Nothing unusual, really, until I put them on and realized this was no ZS5. During the first minute or two of listening to it, it became obvious that the ZS6 was distinctively different from the ZS5 where audio performance is concerned.

Like other Z series IEMs, the ZS6 is available with or without a microphone for hands-free calls. It is also available in three different colors — green, black and red.

Build Quality and Comfort

The ZS6 has nearly identical build quality and comfort to the ZS5. If you’ve not read my review of the ZS5, you can read it here. The only difference is in the construction of the earpieces which are constructed using CNC-machined aluminum (the ZS5 is made out of plastic). The ZS6 also uses the same over-the-ear wires that help secure the earpieces.

This method of wearing the ZS6 may not appeal to everyone, particularly those who wear glasses. From my experience of using the ZS5, it feels moderately comfortable. I personally feel the ZST and ZS3 feel a lot more comfortable than the ZS6 since the ZS6 does not feature an organic shape but this may just be due to my personal preference.

The three sets of ear buds also feel reasonably comfortable although some owners may resort to upgrading their IEM’s with aftermarket ear buds for better comfort, fit and audio performance. At the end of the day, it all boils down to personal preferences and taste.

Audio Quality

As mentiond earlier, the ZS6 has a distinctively different audio performance when compared to the ZS5 although both look visually similar and have the same number of balanced armatures and dynamic drives. When I first tested out my ZS6, it was very obvious that KZ’s latest IEM’s are better than the earlier ZS5. This revelation took me by surprise as I wasn’t expecting much from the ZS6.

Now, i’m not the kind of person who uses complicated and cryptic words to eloquently describe audio quality of earphones just to sound like an informed audiophile. To put it plainly, audio on the ZS6 come across clearer and sharper than the ZS5. Bass is just as punchy as on the ZS5 but seems to be less sloppy and boomy. The ZS6 has a more pronounced “V” audio signature while the ZS5 sounds a little bit warmer. The ZS5 also sounds a bit muffled across all frequencies.

That doesn’t mean the ZS5 is a failure. For a pair of IEMs that cost roughly $20, i’d say it has excellent audio performance. It’s just that the ZS6 seems to perform on a totally different level where clarity and sharpness is concerned.

I have a feeling that soon after the release of the ZS5, the engineers at Knowledge Zenith decided to take a deeper look into it to see how they can improve on its performance. It may be that they discovered a few things, tweaked around with it and decided to re-release the ZS5 as a new model without even bothering to redesign its exterior. I’m no engineer myself but I think the improvement in audio quality may be the result of using aluminum for the open chamber construction and the repositioning of the balanced armatures.

Like the ZS5, the ZS6 has two dynamic drives (10mm and 6mm) and two balanced armatures for each piece. All four drives cover a wide spectrum in audio frequency. The dynamic drives reproduce sounds in the lower frequencies while the balanced armatures handle high frequencies.

In the ZS5, one balanced armature (BA) is positioned near the nozzle while another one is positioned deeper in the chamber and closer to the two dynamic drives. In the ZS6, both BA’s are positioned next to each other near the nozzle. The ZS6 is also an “open” IEM which means it has aluminum chambers that feature grilled vents at the rear to allow air pressure to escape when the drives are operating. This could be the reason why the ZS6 sounds clearer than the ZS5. The chambers of the ZS5 are fully enclosed and there are no vents which may explain why it sounds a bit muffled. Another key difference is the impedance — 15 Ohms on the ZS6 and 8 Ohms on the ZS5 though I’m not too sure how the higher impedance on the ZS6 actually helps it perform better, if at all.

All these subtle changes result in the ZS6 being a very impressive IEM that costs less than $50 but offers performance that is similar to IEM’s from big name brands that cost two to three times as much. I’ve used my ZS6 for listening to music, watching movies and playing games on my smartphone, PC and tablet and it has so far performed remarkably well.

When testing the ZS6, I plug it directly into earphone jacks and do not use any kind of amplifier. I guess this is probably going to be the most typical way how many ZS6 owners would use their IEM’s. With an impedance of just 15 Ohms on the ZS6, most devices such as smartphones and laptops that have low-power audio outputs should have no issues delivering reasonably good audio signals to the ZS6.

It’s possible that the ZS6 may perform slightly better if used with an amplifier but this review is meant to showcase the ZS6 in its original form sans upgrades. Additional stuff such as amplifiers and aftermarket ear buds and cables may help in delivering better audio on the ZS6 but those are topics for another review which I hope to publish in the near future.

For those who want to make the ZS6 wireless, there are Bluetooth modules that you can replace the cables with. Such modules also have playback and volume control. The KZ ZS6 with built-in microphone is currently available at GearBest for $45.50 shipped. Click here for more details.

About the author

Adrin S

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