KZ ASF Earphone Review | Misstep

KZ ASF review featured

KZ Acoustics (Knowledge Zenith) is here again with another in-ear monitor. This time, it’s the KZ ASF, a multi-BA earphone with 5 balanced armature drivers per side. The ASF sports a metal faceplate with a resin body and it’s big. Very big.

Disclaimer: This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.


  • Solid build quality
  • Detachable cable

  • Poor treble extension
  • Harsh upper midrange and lower treble
  • Recessed midrange
  • Poor vocal clarity

Package and Accessories

Box front

The ASF comes in the standard KZ black box.Inside are the KZ ASF earphones, 3 pairs of silicone eartips and a detachable 2-pin 0.75mm cable.

Design, Comfort & Noise Isolation

KZ ASF faceplates

The ASF has aluminium faceplates with a raised crisscross design for added visual interest. Its resin housings are quite bulky – in fact, they’re some of the biggest universal IEM shells I’ve ever seen. Within the transparent shells you can see the white acoustic chamber and some of the balanced armature drivers.

Because it’s an all-BA unit, the housings are non-vented and fully-closed. Despite that, I didn’t experience any pressure buildup in my ears. The aluminium nozzles are slightly narrower than average but have the usual lip and protective metal mesh cover.

KZ ASF inner shells and internals

Although they’re huge, I find the ASF to be quite comfortable. There’s a large scooped out region to accommodate the antihelix so the majority of the housings fill the ear concha. Regardless of that, the shells still manage to protrude out from the ears.

Due to the non-vented design the noise isolation is quite good so the ASF is suitable for noisy commutes and public spaces.

ASF with Shanling UP4 and iPhone.


Gear used for testing

  • PC -> iFi Audio Zen DAC
  • iPhone with Shanling UP4
  • Sony NW ZX-300

The KZ ASF has a heavy V-shape sound signature with a focus on mid-bass and upper midrange/lower treble. It’s quite power efficient and can be driven to loud volume with any source.

KZ ASF frequency response graph
KZ ASF frequency response.

The ASF bass had a mid-bass focus and shows good punch and impact. Being all BA-driven, the attack and decay are fast and the bass is well controlled. It has a fairly mature tuning and by that, I mean it’s not excessive in terms of quantity.

Sub-bass extension is fair but the rumble is signature BA which means you hear it more than you feel it. Overall, I think the ASF bass is decent but is fairly cut & paste and uninspiring.


The lower midrange is recessed but the upper midrange leaps up and plateaus from 1.5kHz almost all the way to 4kHz. This produces a strange mix of thin but muddy vocals and a midrange that sounds harsh and overcrowded. Even on simple tracks, the ASF struggles to resolve and creates a hot wall of sound.

Katatonia’s “Soil’s Song” sounds atrocious on the ASF and melts into a white haze of upper midrange glare. It lacks clarity, the vocals sound muffled yet at the same time, the song sounds harsh and shrill.


The ASF treble is defined by a very large lower treble peak followed by a rapid upper treble fall off. What you get from this is a treble that lacks sparkle and extension yet at the same time, causes fatigue. The poor treble performance is the final nail in the coffin for a tuning that seems bizarre and almost randomly generated.


Stage width is quite good and reaches to the edge of the headspace. Depth is fairly shallow and there’s very little layering of any sort. Instrument separation is poor and imaging is below average.

KZ ASF bottom shell


The KZ ASF is a strange release from the budget ChiFi giant. It disappoints on all levels from the huge shells to the sunken yet shouty midrange and one-dimensional treble response. It seems almost like a pure money grab using a high driver count as bait for the unaware. As such, I advise you to steer clear of this earphone.

  • Impedance: 18Ω
  • Earphone sensitivity: 105dB/mW
  • Frequency range: 10-40000Hz
  • Interface: 3.5mm
  • Plug Type: L curved
  • Cable Length: 1.25m±5cm
  • Colour: Black, Blue
  • Earphone interface: 2-Pin 0.75connector

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