KZ ZST Review

I must say I was very excited to try these headphones. Finding balanced armature drivers in the budget headphone segment always impresses me; dual drivers do as well – this is the first time I’ve seen both of these qualities in a single pair of headphones and I was intrigued to see how KZ did at fine tuning and balancing the characteristics of these two different drivers.
My first impressions were mediocre; the size of the sound-chamber is quite large and it took me a while to get the tips situated properly.
I next realized that the sensitivity of these IEM’s is quite low and I had to crank up the source to get a reasonable volume level.  This lack of efficiency must be due to having more drivers to push.
Soundstage and High-End:
Once I had the drivers hopping I reached out to feel through the soundstage and again was confronted with a mediocre impression – the soundstage felt reasonably wide but the instruments felt somehow crowded together.  Not the most inspiring, but not the worst.
Looking back over my notes from first impression listening to Alphaville’s ‘Big in Japan’ (BIJ), under ‘high-end’ I scrawled ‘blaringly painful’ and left it at that.  And this really sums up the first and last relevant point regarding these headphones – the treble is just horrible.  Like really awful – grating, distorting, sibilant, whatever adjective could negatively describe this frequency of sound would likely apply here.  This is a deal-breaker and overshadows any other redeeming qualities these headphones might have.  The problem could potentially be helped by aggressively tuning these IEM’s but customers shouldn’t have to correct this level of error.
Like I said, I really wanted to like these headphones and, in the interest of giving them a fair shake, I even burned them in for over 20 hours thinking that perhaps the trebble would be reigned in and join the other registers in some semblance of a coherent sound; I regret to report that it was all for naught.
Mid-Range:
The mid-range sounded quite good on these – I was impressed with the realisting sounding drums on The Doors ‘Texas Radio and the Big Beat’ (WASP).
Bass:
This is certainly the most impressive part of these headphones and rightfully so, the dynamic driver is solely responsible for providing deep accurate bass as the balanced-armature is responsible for making you grit your teeth.
Dr. Octagon’s ‘Earth People’ was suitably punchy and impactful while The Dave Brubeck Quartet’s ‘Three to get Ready’ showed up with remarkably detailed stand-up bass which was incredibly enjoyable to behold.
Conclusion:
There’s a lot to like here but savage high-end mars the whole experience.  These could potentially be salvaged with aggressive eq settings but why bother; check out a single dynamic driver from KZ that blows these away off the shelf – KZ ZS3