Knowledge Zenith (KZ) ED9

REVIEW: Knowledge Zenith (KZ) ED9


Frequency Response: 7-46200Hz (?)
Sensitivity: 108dB
Input Impedance: 18Ω

Price: not sure about the retail price, but it goes under $20


  • 4 pairs of silicone tips (1xS, 2xM, 1xL)
  • 2 pairs of interchangeable nozzles



The KZ ED9 model looks quite nice on its silver and gold mix; silver housings and golden nozzles, both made of aluminum. Strain relief is flexible but a bit short. Cable a bit rubbery, doesn't hold a memory effect, but is kind of springy and average on microphonics. The plug looks well made from the outside, but can't really say about the internal QC, as some noise was noticed at times when just touching the plug.

Fit, Comfort and Isolation:

No issues here. The housings' shape is rather straight, not too wide or long, so the fit is quite easy. While they do feel just a bit heavy on hands, they stay fixed once on the ears without any discomfort.
Isolation is quite good. The large vents on the back don't seem to have any negative effect.


There've been many good impressions about the high SQ performance of the Knowledge Zenith earphones for their very affordable prices. While this is the first KZ model I get to try, I can now confirm what the whole 'hype' is about. For something that goes below the $20 range, the ED9 offer a really good sound, not just for 'quality for price' alone, but as a whole musical experience.

While the ED9 feature exchangeable nozzle, the overall signature leans towards the warm, very warm, and bassy side of things, but still very smooth and enjoyable.

Starting from the low frequencies, they're obviously dependant on the nozzle choice. With the 'bass' ones, the bass is very prominent and dominant, quite strong and full-bodied. Quantity wise it is not far from being classified as a bass-cannon with an unforgiving impact. Fortunately, it manages to keep a more than acceptable level of control and doesn't really lack in detail for the asking price. Sub-bass is quite good, actually; reaching the lowest freq. without much effort with a very enjoyable rumble and speed.

Switching to the other nozzles is like almost turning a 'bass gain' switch off. The enormous quantities turn into a just north neutral in comparison; but still present nonetheless. The extension remains unaffected, but it's a much thinner and tighter bass, leading to a more balanced overall sound. That said, the whole fun factor is also missing and might be found even boring for some.

Despite the bass results from each nozzle, both midrange and treble remain pretty much unchanged. Yes, there are the obvious effects of the strong bass response, but the positioning and detail differences are less than what would be expected.
With the bass nozzle there's some bass bleed and general warmer tonality from lower to upper mids, while cleaner and a bit thinner and less veiled than with the other nozzles.

The midrange itself is somehow recessed and lacks a bit of presence. Detail and separation are rather good; nothing outstanding, though. Where the ED9 mids' real strength lays is in its musicality factor as it's more focused in presenting a very enjoyable and catching sense of warmth and detail.
Vocals are a bit distant but are sweet and full in body for a bassy earphone. Not my first choice for vocals centered genres, but would take the ED9 over something like the Xiaomi Piston 2 anytime without a second thought.

Treble is very smooth, a bit laid back with just a bit more authority than the midrange, but still kept in the safe zone. It will still give enough energy when really called, though. Upper extension is average, nice for the overall signature. Sibilance is not perceived at moderate volumes, unlike the Piston 2, and it's less grainy at lower highs than a Fidue A31s, but is also less resolving than both.

Stage is wide and deeper than average, but height is not enough to give a whole 3D effect. With the bass nozzles, the ED9 still sounds much bigger than the A31s or the Penon IEM, even without applying extra EQ.


The KZ ED9 is a very strong contender and very well valued for an IEM that just goes under $20. QC aside, the sound is very well tuned and very fun for the warm and bassy signature. Bass is quite addicting, a bit tiring at times, but well meant for bassheads in a tight budget. Not much to add here, simply a new addition to the 'best value' list.