KZ ZSA Review – Shining Armor!

Review by Mhark Jhoshua Q. Torres

The Company

Knowledge Zenith which is more infamous as “KZ” has been the king of sub 1000 php ($20) IEMs in the Philippines for at least 2 years. It is a china based company that produces Single dynamic drivers IEM up to 5 hybrid drivers (4 BAs +1 DD). They are famous not because of its phenomenal sound quality but for being bang for the buck. As we surf the internet, KZ doesn’t have their own website and rely towards online shops such as aliexpress and gearbest.

The KZ ES4


Disclaimer: The review was from Jonjon Manlapaz of UrbanAudiophile and the unit was returned after the honest review, the IEM was subjected for 50 hrs burn in time.

The unit that we reviewed was from UrbanAudiophile, thank you for letting us borrow your unit for a bit. We got the black variant, it comes with 3 different colors which are black, gray and red. It is equipped with 1 DD and 1 BA placed at the nozzle, other technical specifications from their official store are as follows:

Frequency response: 7Hz – 40KHz
Impedance: 18ohms
Sensitivity: 101dB


The box is white the KZ ZSA imprinted on it, it is a sleeve type box which is now typical with KZ IEMs. Inside the box you’ll get a pair of KZ ZSA black obviously, underneath the plastic are 2 more pairs of silicone tips 1 small and 1 large, the medium ones are already attached. lastly the 0.75 mm braided cable with mic is placed in an opaque white plastic, the good thing is that the stock cable is now the former upgrade cable V3. This is an average package for around $20 IEM, we expected nothing more than this.

Fit and Comfort


The shell of the KZ ZSA is very small, might be the smallest among the KZs (starting from KZ ATE). The fit seems to be fine for me, it provides average comfort and average noise isolation, it doesn’t have sound leak as well but the edges sometimes cause some minor pains. The seal is greatly dependent with tips to be used but as far as my listening experience goes it has a decent fit and comfort but it does not touch IEMs like Magaosi K5, Hifiboy OSV3 and QDC Neptune.



‌Mid bass is very impactful, Munimuni’s Bukang liwayway sounds punchy and is far from being muddy, it is a bit smooth with rounded presentation. Texture is so-so while the quantity is good enough especially for non bass head, I love the ES4 more than this one as it is packed with better bass impact. The sub bass seems to go deep and gives justice to deep subs and the texture seems to be pretty decent as well. Overall bass seems to be rather smooth but is very enjoyable as it leans towards fun sounding iem.


‌Mids is slightly recessed, the string instruments and piano seems to be placed behind the bass notes but it seems to be few steps froward than the vocals especially lower mids. The male vocals packs decent amount of body but still sounds a bit hollow for my taste, good thing is that the clarity of mids is pretty good for the price, it doesn’t sound too shrill and it is presented in a quite detailed manner, the texture is there. The “s” seems to be emphasized here, it is more sibilant than the ES4 as it follows the home sound of KZ, but it doesnt sound annoyingly sibilant like the ZS6. Upper mids is definitely more forward and transparent than the lower mids, female vocals are delivered with ease as Reese Lansangan’s voice sounds crisp and clear but may still sound shrill at times.



‌The treble since to reach the borderline of piercing, it’s one step from being piercing, it is the most prominent amongst the frequencies, it has good sparkle and is very crisp. It follows the KZ home sound which is leaning to bright. Cymbals has some slight harshness but has good bite on it especially when compared to the ES4 which has more of warm tonality. The treble seems to take the center stage as it also decays pretty fast thus, it can easily give justice to complex rock and metal songs.

Sound Stage and Resolution

Sound stage is leaning to a medium sized room, it boasts average depth, width and height, it is far from the ZSTs that sounds boxy at times. The lower mids are placed behind the instruments and upper mids, the bass is few steps forward than the mids and lastly the treble takes the front as it is presented forwardly in comparison to the mids and bass. Resolution is okay as it barely passed the Everything’s Not Lost test.

Sound Signature and Synergy

The KZ ZSA seems to have a U sound signature with slight emphasis to the treble, it has good amount of bass, laid back mids and upfront treble while no being to aggressive.


iFi nano iDSD BL

The nano has natural tonality and timbre with close to neutral response, it has very low noise floor good width and length and average height, the nano is also very resolving and has good imaging. The ZSA sounds so clean when plugged with the nano, the mids may sound thin but definitely transparent while still being recessed, the bass has good tightness the sub bass also extends very well. The treble has good texture in it, it is detailed and packs good amount of air, it may sound aggressive with treble heavy tracks but not as much as the ZS6 does. The downside is that the overall body and fullness of the ZSA sacrificed as other technicalities improved (clarity, sound stage, imaging, extension and noise floor).

Smart Phone (Xiaomi Redmi Note 4X)


The synergy is better with my phone as source because it is warm with good fullness across the midrange, the vocals gained lushness but in return it took some steps further and also became quite muddy. The noise floor also increased whereas the slight background hiss is audible, layering and imaging of instruments became incoherent. The bass gained more impact and punch as it loss some details and texture, it doesn’t go deep as when I plugged it with the nano. The highs gained more air and became more peaky giving that splashy feeling when used. With proper warm source I believe that the ZSA will shine better as the overall sound gain more lushness and warmth while still retaining the sparkle up to the treble.



For the bass, the ES4 has better depth, quantity, texture and impact while the ZSA has better tightness and decay speed making it more light and agile as compared to the ES4, but the ES4 has better overall bass as it gives justice with every bass notes from subs to mid bass while not being too boomy. The mids in the ES4 has better warmth in it, the two shares the same timbre while the lower mids of the ZSA being more recessed, the upper mids also goes to the ES4 as it boasts better forwardness and transparency it is also less sibilant as compared to the ZSA, the ES4 won by a notch in the mid section this time. The treble obviously goes to the ZSA, it has better bite and crisp, good sparkle and forwardness as compared to the conservative approach of the ES4. The sound stage is pretty similar, the resolution goes to the ES4 as well as it passed my test with flying colors. The build goes to the ZSA while the fit and comfort goes to the ES4.



The KZ ZSA is fit to be used by bright listeners, it is build like a tank as it is build with pretty solid metal and a 2 pin removable cable. The bass has some good depth, quantity and tightness but lacks impact, the mids has good clarity especially the upper mids but it is recessed and lacks body for the lower mids. The treble took the center stage as it is presented forwardly with good sparkle, decent amount of air, good extension and above average texture, it may sound harsh at times but will please most bright users, given that the ES4 and ZSA shares the same configuration their sound signature seems to be hot and cold so folks, choose your poison (wisely)!



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