KZ ES4 – Review



| Balanced Armature | 10 mm Dynamic Driver |

? KZ ES4 the latest release from KZ with a dual hybrid configuration, detachable cables and plastic housings.

The KZ ES4 is the newer updated version of the KZ ES3, inheriting some of their main technical specifications like: dual driver, plastic housings, detachable cables.

The KZ ES4 features 4 drivers in total, distributed in 2 per earpiece. The dual driver setup includes 1 balanced armature and one 10 mm dynamic driver, each driver will independently be responsible of reproducing different audio frequencies – the dynamic driver will take care of the lower end while the balanced armature will resolve mid and upper frequencies.

The KZ ES4 belongs to the newest generation of KZ in-ear monitors and shares some design similarities with the KZ ZS10, like the transparent housings and the characteristic divider board with the KZ logo which can be found inside the rear section of the housings.

The form factor of the earpieces share some of the curvy shapes of the KZ ZST and KZ ZS10 but have a rear housing’s design that (if seen flat) looks nearly identical to a guitar pick.

The KZ ES4 durability is inline with all KZ earphones from the last 2 years – that are built with the same materials. Expect the same rugged and well-built construction of the KZ ZS10, KZ ZST PRO and KZ ED12.

The cables are the same one that comes with the KZ ED15 and KZ ZS10 with a dual double helix braided design and very rubberized finish. The connector of the cable is the same bi-pin 0.75mm of all KZ earphones with detachable cables; specifically they use the angled connector (like the KZ ZSR, KZ ZST and KZ ZS10) and not the straight connector that came with the KZ ZS6, KZ ZS5 and KZ ZS3.

The KZ ES4 price is lower for the KZ ES4 mic-less version, but only marginally cheaper.

The KZ ES4 is compatible with Android and Apple devices.

You can buy the KZ ES4 in:

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KZ ES4 Review

Tests & Scores



KZ ES4 weight in Ounces and KZ ES4 weight in grams. Weighted with and without their cables.

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Accessories & Packaging

The KZ ES4 unboxing results in 3 pair of eartips and the detachable bi-pin cable. Everything comes inside a small rectangular packaging with a sliding cover, the standard packaging of KZ’s latest earphones like the KZ ZS10, KZ ED15 and also very similar to the RevoNext QT2 and some Xiaomi In-Ear Headphones.



Bass & Sub Bass

The KZ ES4 bass is super strong with extra punchy mid-bass and sub-bass that reaches extremely deep levels. You can listen to the most bass-intensive and demanding tracks that you can imagine and the KZ ES4 will easily deliver all the bass needed. If you own other KZ earphones like the KZ ZSR, KZ ES3, KZ ZST you can get an estimated idea of what the KZ ES4 will provide.

Applying an EQ, their mid-bass gets insanely punchy and depth becomes out of this world.

During our extreme bass tests the KZ ES4 were able to handle 40% of the maximum power of a Fiio E12 amplifier while being set to high gain and with bass boost turned on; a custom basshead EQ was used. The extreme amplification and equalization, made lower frequencies of the KZ ES4 achieve a massive increment of mid-bass punch and sub-bass depth that even provided a crazy basshead level of impact and rumble way above the Xiaomi Mi Pro HD, Monoprice 8320 and even stronger than the Xiaomi Mi In-Ear Headphones Pro but not as impacting as the Sony MDR-EX650, Sony MDR-EX800ST and Pioneer SE-CX8.


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Mids & Vocals

The KZ ES4 mids have full bodied sound with a warm personality and very crisp higher mids. Lower vocals sound energetic and alive despite a mild presence of mid-bass bleed. If you were not into KZ’s new approach with the tuning of the KZ ZS10, you will be happy to know that the KZ ES4 has KZ’s sound signature that everybody loves. The KZ ES4 has a very strong output and if you crank the volume you will feed their crisp higher mids into some harshness.

With an EQ you will be able to customize their lower mids and male vocals into absolutely clear and free of mid-bass bleed. Higher mids can be EQ’ed to calm down some of their harshy peaks without getting recessed.





Highs & Treble

The KZ ES4 highs are very bright and resolve a strong amount of detail right out-of-the box. Much like their bass and mids, their highs are tuned with KZ’s classic style, relatively inline with the style of the KZ ZS6, KZ ZST PRO, KZ ZSR and KZ ZS5. As with most earphones tuned for very bright highs, some piercing highs might show up depending of the peaks of each track; sibilance is fairly smooth.

An EQ adds a jaw dropping amount of brightness and become noticeably more detailed. Piercing highs can also be efficiently eq’ed to reduce their strength.




Sound Leak

The sound that leaks out of the KZ ES4 is very low. While listening to music at a moderate volume their sound leaking levels will be imperceptible by nearby people. If you set the volume to the very maximum people next to you will hear a very subdued leakage (if first you do not become deaf by their super strong volume output)


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Sound Isolation

Noise isolation of the KZ ES4 is highly efficient, with a level of reduction of surrounding noises far stronger than most average earphones. You can set your volume within moderate and they will still provide a near absolute isolation, by cranking the volume just a bit higher the will isolate you completely from noises.


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With a form factor very similar to the KZ ZST, the KZ ES4 offer the same outstanding level of comfortable and secure fit. Regarding size, the KZ ES4 are not as large as the KZ ZS10; instead, they have a footprint more inline with the KZ ES3, KZ ED12 and smaller than the KZ ZS6.

Much like most of the latest generation of KZ earphones, the KZ ES4 is a very comfortable earphone to wear and does not generate in-ear pain.


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Response to Equalization

The response to custom equalization of the KZ ES4 was outstanding, bass could be empowered into insane levels of punch and depth; lower vocals got very clear and mid-bass bleed was nearly extinguished; highs became extra bright and open-sounding.


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Scores Scores

KZ ES4 Scores

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Frequency Response (raw)

KZ ES4 Frequency Response Curve

KZ ES4 Frequency Response Curve - Right Side
KZ ES4 Frequency Response Curve – Right Side
KZ ES4 Frequency Response Curve - Left Side
KZ ES4 Frequency Response Curve – Left Side

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KZ ES4 Technical Specifications

Driver Unit10mm DD + BA
Power Capacity3mW
Impedance25 ohms
Frequency Response20-40,000Hz
CordY-type, round cord
Cord Length1.2m
PlugStereo mini plug
WeightApprox. 20g
Supplied Accessories3x Earphone tips; detachable cable

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How many drivers does the KZ ES4 have?

The KZ ES4 is a dual driver headphone. Which means that the KZ ES4 has 2 drivers per side.

What type of headphone is the KZ ES4?

The KZ ES4 is an in-ear headphone.

Does the KZ ES4 have a microphone?

The KZ ES4 have a microphone and a remote.

Which KZ ES4 colors are available?

The colors available for the KZ ES4 are: Cyan, Green, Black.

What is the price of the KZ ES4?

You can check the most up-to-date price of the KZ ES4 by following THIS LINK.

Where can I buy the KZ ES4?

You can buy the KZ ES4 at:

How many eartips does the KZ ES4 include?

The KZ ES4 includes 3 pair of eartips.

What cable do the KZ ES4 have?

The KZ ES4 have a detachable, Y-type, rounded cable.

What cable connection does the KZ ES4 have?

The KZ ES4 cable connection has a 0.75mm Bi-Pin interface with a 3.5mm mini stereo plug.

Are there replacement cables for the KZ ES4 ?

The KZ ES4 cables can be replaced with 0.75mm bi-pin replacement cables.

Are there upgrade cables for the KZ ES4 ?

The KZ ES4 uses 0.75mm bi-pin cables which are very popular standard cables. You can buy any cable with a 0.75mm bi-pin connector to upgrade the cable.

Does the KZ ES4 have Bluetooth / The KZ ES4 is a wireless headphone?

The KZ ES4 does not have Bluetooth but you can buy Bluetooth cables to make the KZ ES4 Bluetooth-enabled headphones.

Is the KZ ES4 compatible with Apple devices?

The KZ ES4 is fully compatible with Apple devices.

Is the KZ ES4 compatible with Android devices?

The KZ ES4 is fully compatible with Android devices.


KZ ES4 Photos

We highly discourage anyone from trying to apply our testings to your own earphones, the risk of damaging or permanently breaking your iems is absolutely probable to happen. With our standardized equalization and amplification tests we push the limits of the earphones to the extreme. If anyway you decide to do so, we cannot be held responsible of the damage done to your equipment. Do it at your own risk.