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KZ ZS4 (Knowledge Zenith)

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    Brand: KZ Acoustics

    Model: ZS4


    Driver/Transducer: 1+1 (8mm dynamic driver + 1 balanced armature)

    Wire length: 1.2m (approx. 3.9 feet)


Recent Reviews

  1. B9Scrambler
    KZ ZS4: Having fun yet?
    Written by B9Scrambler
    Published Feb 12, 2019
    Pros - Comfort - Isolation - Big, boisterous sound
    Cons - Subpar material quality - Might be too bright and/or too bassy for some

    Today we're checking out yet another hybrid in KZ's ever expanding lineup, the ZS4.

    Back in 2016 KZ released the ZS3. It along with the ZST signalled a new era for the brand. While the ZS3 stuck with a single dynamic driver per side, it featured a much more complicated housing design heavily influenced by the Fit Ear Stagediver series, but more importantly, removable 2-pin cables. In my opinion it was a pretty awesome little earphone, though many found it lacking energy in the treble.

    The ZS4 revisits the basic tenants of the ZS3 while making a few adjustments and enhancements along the way. Is it a better product as a result? I sure think so.


    Many months ago I had the chance to try out the ZS4 thanks to a local Head-fi'er. I liked it so much I went home and bought one on AliExpress with the intention of reviewing it. A couple weeks later, Canada Post went on strike and what do you know, my ZS4 never showed up. Since shipping costs to Canada skyrocketed following the strike, I didn't bother ordering another.

    In November Sunny from Better Audio on Amazon reached out to see if I would be interested in checking out a few products they sell, one of which included the ZS4. Given the experience above, I agreed to write a review. They provided a tracking number and... that one never arrived. Canada Post was on a roll! Another attempt made and finally, after yet another month, a ZS4 showed up on my proverbial doorstep (I live in an apartment).

    The thoughts within this review are my own, based on time spent listening to the ZS4. I don't review graphs, though that would be easier and save me a lot of time. The subjective opinions within do not represent Better Audio, or KZ, or any other entity for that matter. At the time of writing, you can pick up the ZS4 for 18.99 USD here on Amazon.



    The ZS4 was run primarily with either a Shanling M0 or ES100 paired over LDAC to my LG G6. The F.Audio S1 and HiFiMan Megamini also worked nicely with it. The ZS4 does not need to be amped and can get up to volume with little effort. I prefer it with neutral to warm sources. Bright sources like the Ruizu X02 and Walnut V2S sound too harsh.

    Personal Preferences:

    I listen primarily to various EDM sub-genres (liquid drum and bass, breakbeat, drumstep, etc.), hip hop, and classic rock. My preferences for earphone tuning are quite relaxed and as such their is no one signature I look for. The HiFiMAN RE800, Brainwavz B400, and Massdrop x MeeAudio Planamic are examples of earphones with wildly varied signatures that are enjoyable for different reasons. I generally listen at very low volumes, so keep this in mind when perusing my thoughts on how an earphone sounds.


    • Driver: 1 BA + 1 DD
    • Frequency Response: 7-40,000Hz
    • Impedance: 18ohms
    • Sensitivity: 101dB/mW
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    Packaging and Accessories:

    The ZS4 arrives in a package that will be familiar to the KZ brand faithful. The front of the white exterior sheath shows off a coloured, digital representation of the ZS4's shells along with the model name. Flipping to the back you find a list of specifications as well as location and contact information for KZ. Sliding off the sheath you are greeted to the ZS4's ear pieces set within a KZ branded plastic insert. Underneath are all the accessories. In all you get:
    • ZS4 earphones
    • 0.75mm 2-pin twisted cable
    • Silicone eartips (s/m/l)
    • Manual and warranty card
    This kit is standard KZ through and though, or is it? While the tips look like the same old 'Starlines' that KZ has been including for a while, on closer inspection you find there is a mimic in our midst. Looking at the preinstalled medium tips, you notice the silicone is thinner and quite flimsy which leads to them easily detaching from the nozzle. Standard Starlines are rounded at the edges of the bore, whereas these feature a sharp ridge. Anyone who follows my reviews knows I like 'Starline' tips a lot and use them with a ton of different earphones. These tips feel like a cheap knockoff, are a disappointment, and were promptly replaced with a proper set of 'Starline' tips. At least the small and large spares were normal.

    Build, Comfort, and Isolation:

    I bought into the ZS3 on release, getting mine with the first wave that was sent out to buyers following an early recall for crushed sound tubes. When it arrived, I was impressed by the high quality matte plastics and rock solid feel. While the ZS4 looks basically the same, it's not. The lipless nozzle is gone, replaced by one with a prominent lip. With proper tips, it holds them on exceptionally well. The housing also tapers in more sharply lending the ZS4 to a deeper, more comfortable fit. It is also very lightweight which also contributes to the ZS4's above average fit and comfort.

    The plastic KZ went with feels like a downgrade from that used on other models like the ATR, ZST, ZSN, and well, pretty much every other modern KZ. Plastics on my very early ZS3 (the one with the extra thick 2-pin connectors) feels more dense and durable, while the ZS4 feels right in line with the current glossy black version of the ZS3. Flicking it with your fingernail results in a somewhat cheap, hollow, clicky sound. The plastics are also slightly greasy. Fit and finish is fine, but a step down from other Kzs as gaps between the two halves of the shell are larger on the right side. The metal nozzle mesh could have been installed with more care since there are s few frayed strands of metal that could prick your finger when installing tips. Overall, the build of the ear pieces is serviceable. I suspect KZ outsourced it to a different manufacturer than normal since this is the only KZ in recent memory that feels this average.

    At least they win back some points with the cable. The ZS4's cable is very similar to something you'd get from TRN. Unlike the vast majority of KZs which include a copper coloured quad-strand braided cable, or the old brown-sheathed ones, the ZS4's includes a tri-strand twisted cable with a slightly rubbery black sheath. Hardware like the y-split and plug are the same chunky, angular VSonic inspired parts you find elsewhere in the lineup. The shrink wrap used on the memory wire is softer and thicker than what KZ typically uses, and the wire doesn't hold bends quite as well. Still way better than most of the competition, just not quite up to the standards I expect from KZ. This is a good cable overall and while I prefer the copper-coloured quad-strand cable found on their other models, but this one is pretty solid.

    Isolation is outstanding since the ZS4 basically fills the entirety of your outer ear with it's fairly large ergonomic body. Not much sound gets by. If you decide to listen with foam tips, you're going to lock yourself into an even deeper chamber of silence. Well above average isolation here compared to your typical dynamic driver based earphones.

    IMG_5865.JPG IMG_5867.JPG


    I remember having fun in this hobby. Do you? If not, you should give the ZS4 is listen because this is the definition of a fun earphone. With a powerful v-shaped signature, it has a well-paced sound that rocks your skull while your fingers and toes tap out the beat. Turn your brain off, forget about those frequency response charts you've being eyeing so lustfully, and just enjoy the music.

    The ZS4's upper regions are elevated giving high pitched effects lots of presence, yet it remains smooth, crisp, and surprisingly fatigue free. You can absolutely crank Skrillex's “Scary Monsters and Nice Sprites [Zedd Remix]” without worry that the bright effects dotted throughout the track will deafen you. And this is coming from someone that typically listens at well below average volumes. Yeah, treble sensitive people will find something to complain about. If someone can find the ZS10 bright then this'll be unbearable, along with 90% of the product on the market. Every ear is different. Me? I don't find the ZS4 bright at all. Elevated, yup, but also quite smooth and fairly refined.

    Since the upper treble is seeing a bump in emphasis, the ZS4 has quite an airy feel to it that gives the presentation a good sound stage. Since the lower treble also has a mild peak, clarity down into the mid-range is pretty impressive, even if it is recessed. On The Doors' “Break on Through (Infected Mushroom Remix)”, Jim Morrison's vocals clearly take a back seat to the electronic instruments and remixed guitar. Even so, his words are easy to follow and legible thanks to the ZS4's impressive clarity. However, on more vocal focused tracks like Massive Attack's “Risingson”, 3D and Daddy G's moody singing slots in perfectly amidst the rest of the mix and certainly isn't overshadowed. The same could be said on “Teardrop” where Elizabeth Frasier sounds magnificently seductive.

    Bass is the ZS4's raison d'etre and oh boy does it deliver. The slap of the drums on Massive Attack's “Inertia Creeps” have impact and gobs of texture. The deep bass in the opening of Kavinski's “Solli” thunders through your eardrums. The machine gun double bass in Havok's “Covering Fire” is defined and separated without smearing notes together. This is one of KZ's better applications of a very bassy dynamic and should be on the radar of those wanting something inexpensive and bass heavy that also happens to be technically competent.

    As noted earlier, the ZS4 has a solid sound stage. I'd put it above average with more depth than width present. As a result, imaging is accurate with clean channel to channel transitions. It's not quite as precise and accurate as more expensive earphones, but plenty good for the price. I never found it congested even in busy moments like the closing couple minutes of King Crimson's “Starless and Bible Black”. Layering and separation are on par with other hybrid earphones in the segment, which is to say it effectively spreads out individual track elements.

    The ZS4 is a bass cannon with enough treble and mid-range presence on hand to keep everything clear and well-defined. As said earlier, this thing is simply fun to listen to. If I feel like nitpicking, it still holds up well to scrutiny thanks to some solid technical fundamentals. I love this thing.

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    Select Comparisons:

    ZS3: If you enjoyed the ZS3 but found it a little lacking in the treble regions, the ZS4 will be right up your alley. It’s got more detail, sparkle, and better extension which also results in a larger, more airy sound stage, and the ZS3 was no slouch there. Bass extends even better on the ZS4 easily giving off a sub-woofer style feel that you get from older models like the original ZS1. The mid-range doesn’t stand out as much here as it did on the ZS3 thanks to the treble from the added armature. While I feel the ZS4 is a direct upgrade of the ZS3's sound, I can see some referring the ZS3's due to a more mellow treble presentation.

    ES4: The ES4 is not my favourite KZ, and pitting it against the ZS4 highlights everything I dislike about it. The ES4's treble lacks upper end emphasis and comes across somewhat dull. The mid-range is more forward on the ES4 but lacks clarity and comes across veiled. Bass is nearly as prominent but rolls off early and is way too focused on the mid-bass regions. This leads to it sounding overly thick and stuffy. The ES4 has a smaller, more confined sound stage though it is more precise with imaging. Layering and separation are better on the ZS4. There is no situation where I would ever pick the ES4 over the ZS4, but as always, some will definitely prefer the ES4's more laid back, mellow presentation and more prominent mids. The lack of clarity and congestion have me leaning strongly in favour of the ZS4 though.

    Final Thoughts:

    The Oxford dictionary defines fun as “amusement, especially lively or playful.” While what is construed as amusement, lively, or playful may differ from person to person, the ZS4 embodies these qualities for me. It's bouncy and playful and acts as a pick me up which is something neutral earphones simply can't do in most instances. Yeah, the ZS4 probably measures like crap, but who cares when it is so damn amusing? It's not natural. It's not realistic. The ZS4 is an exaggerated break from reality that plasters a smile across your face and draws a chuckle from how absurd the bass can be. Sit back, relax, and take a chill pill.

    Thanks for reading!

    - B9Scrambler

    ***** ***** ***** ***** *****

    Some Test Tunes:

    Aesop Rock – The Impossible Kid (Album)
    Hail Mary Mallon – Are You Going to Eat That? (Album)
    King Crimson – Lark’s Tongues in Aspic (Album)
    King Crimson – Starless and Bible Black (Track)
    Supertramp – Crime of the Century (Album)
    Infected Mushroom – Legend of the Black Shawarma (Album)
    Gorillaz – Plastic Beach (Album)
    Massive Attack – Mezzanine (Album)
    Fleetwood Mac – Rumors (Album)
    Run the Jewels – Run the Jewels (Album)
    The Prodigy – The Day is My Enemy (Album)
    Tobacco – F****d Up Friends (Album)
    Felt – Felt 2 (A Tribute to Lisa Bonet) (Album)
    Michael Jackson – Thriller (Album)
    The Crystal Method – Grace (feat. LeAnn Rimes) (Track)
    Jidenna – Long Live the Chief (Track)
    Skrillex – Ragga Bomb (Track)
    Big Grams – Run for Your Life (Track)
    Funkadelic – Maggot Brain (Track)
    Aesop Rock – Fishtales (Track)
      williamclarkonet and DocHoliday like this.
    1. DocHoliday
      After reading this review I am suddenly ashamed that I've hesitated on picking these up. That's something I must remedy....quickly.
      DocHoliday, Feb 12, 2019
      B9Scrambler likes this.
    2. B9Scrambler
      They're fun man. Well worth a listen imo.
      B9Scrambler, Feb 12, 2019
  2. Nimweth
    |Affordable Enjoyment
    Written by Nimweth
    Published Jan 2, 2019
    Pros - Entertaining sound with powerful bass response, clean bright treble.
    Excellent fit and isolation
    Cons - Some mid-bass bleed, bass can dominate occasionally
    Mids a little recessed
    The ZS4 is the latest hybrid design from KZ amongst their recent batch of new releases. It is a dual-driver IEM featuring an 8mm dynamic driver for the bass and midrange, and a balanced armature for the upper frequencies. In this case the latter is the now familiar 30095 unit seen before in various KZ hybrid IEMs such as the ES3, ES4, ZST, ZSN, etc.

    Presented in a simple white box with a picture of the earphones on the outer sleeve, a black plastic tray contains the earpieces, which have a medium-sized set of eartips pre-fitted. Below this you will find the detachable 2-pin cable and two further sets of silicone tips, which are the excellent KZ Starline type. The cable is a new design featuring a black braided wire and a stocky right-angled 3.5mm plug. The Y-split is the standard chunky one seen before in other KZ IEMs. There is no chin slider.

    The earpieces are made from a clear, light, hard plastic in bright red colour. (They are also available in black). The left and right channel identification is displayed on the earpieces in a hand-written font along with the legend “hybrid technology”.

    They are based on the ZS3 and have a complex knobbly shape which is designed to fit inside the ear cavity, and does so very comfortably. The fit using the pre-installed tips was very good. Inserting the earpieces and looping the memory wire round the ear, and then rotating the earpieces backwards about 30 degrees gave a perfect comfortable fit and seal. I found I could wear them for hours like this with no problem.

    I employed my usual method of burning in before testing which involved running in for over 100 hours before listening critically. Initially I found the balance to be somewhat bass-heavy with a bright, sometimes sharp treble, but after the 100 hours burn-in the overall balance became mildly “V-shaped”, resulting in an exciting and entertaining sound. I have to say that these earphones were transformed by burning in more than any others I have tried.

    The main source for auditioning was a Hifi Walker H2 DAP via line out with a Fiio L16-A2 cable and a Fiio A5 headphone amplifier. I found the ZS4s to be reasonably efficient and obtained a good output level both via the normal headphone socket on the H2 as well as via the line out. I tested the ZS4s with a wide range of music across various genres.


    I already have the ZST, ES3 and ZS10 models which feature the 30095 armature driver for comparison. The immediate impression was of excellent clarity. The 30095 balanced armature displayed good texture and detail, having a very attractive delicacy in the upper register. Running a glide tone did reveal that there were some peaks in the treble but these were handled well, with only occasional harshness on high notes. There was a mild lift in the presence region which gave the sound an enjoyable immediacy. I would guess that the crossover point has been set at a lower frequency in this model compared to the ZST and ES3.

    As the treble settled down it revealed a surprising level of detail. A good example of this was in “A story from the Rain” by Richard Burmer. This is a synthesiser sound-picture with lots of atmosphere. At the beginning, and near the end, there is the subtle sound of rain falling. This is at a very low level but the ZS4s reproduced this well, a very impressive performance given the price of these earphones.


    The midrange was not too recessed, only appearing so in bass-heavy tracks. I found myself enjoying my music more that I had been doing for a while, having recently used more neutral-sounding IEMs. Vocals came over very well, Chris Izaak’s “Wicked Game” being a good example, with his voice clearly featured above the guitar and bass accompaniment. Lyrics were easy to discern, as evidenced in Richard Marx’s “Hazard” where the narrative was simple to follow.


    Bass response was deep and powerful. It reached well into the sub-bass yet was not boomy or overwhelming. It was somewhat north of neutral and there was a small amount of bleed into the midrange. I was surprised how good classical music sounded. The warm mid-bass gave an attractive bloom to cellos and basses and emphasised recorded ambience, bringing the atmosphere of the recording venue into focus. “In Church” from the “Slovak Suite” by Novak sounded wonderful with the organ accompaniment displaying plenty of depth and power and the strings having a smooth, lush quality. There was plenty of impact, too, with the deep drum sounds in “Komarov’s Fire” by Richard Bone displaying excellent slam and power.


    The ZS4s displayed a surprisingly good soundstage with good width and depth. The placement of instruments within the stereo image was also very good, which suited classical music well. In the “Suffolk Suite” by Doreen Carwithen, the sound of the strings, woodwind and brass was well balanced, all the sections of the orchestra emanating from the correct location.

    Simpler tracks showed great intimacy. “I Wonder (Departure)” from Benny Andersson’s solo album “Piano” showed the ability of the ZS4s to reproduce the decay and harmonics necessary to hear the natural sound of the piano. The ambience and reverb in the recording was excellent. You could really imagine yourself in the room with Benny and his Fazioli instrument.

    These are probably my favourite product from KZ so far. I have owned and tested seven models from their range and I definitely prefer these to the ZST, ES3 and even the ZS10. They improve on these with a superior treble response which is clearer and more expressive. They have a V-shaped, fun tuning without sounding unbalanced. With a comfortable fit, excellent seal and isolation and a very affordable price, they deserve an unreserved recommendation.


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      williamclarkonet and DocHoliday like this.
  3. DallaPo
    KZ ZS4 | Rating: 7.8
    Written by DallaPo
    Published Dec 12, 2018
    Pros - bass with pressure
    detailed treble
    Cons - blending midrange bass
    sometimes sharp peaks
    The KZ ZS4 is to be understood as an upgrade to the ZS3. The same housing as its predecessor now contains a hybrid configuration consisting of a BA and a dynamic driver.
    In contrast to the ZS3, the BA driver brings more brightness and clarity to the music, but also sometimes wants too much.
    From time to time I'm not quite so clear about the criteria according to which KZ distributes their product names. If you assume that the ZS* series was actually reserved for their flagship models, the ZS4 doesn't really fit in.
    Out of competition are currently their pure BA driver models, which have also received new series designation (BA* & AS*).

    In terms of appearance and material (plastic), the ZS4 is a copy of the ZS3, as already mentioned, but with slight changes to the sound tube, which is no longer as thick, but just as long. I have to admit, that I always have my problems with longer tubes (ZS3, ZSR), because no matter what tips I use, they press and cause pain in the long run. So also unfortunately here. But this is my personal problem and a subjective evaluation.

    Otherwise, the design is very ergonomic, so that the ZS4 fit very well in the ear, provide excellent insulation and are also suitable for sports activities.

    As with all models, the scope of delivery is the same (cable, three different silicone tips).

    If the ZS3 was already an in-ear for bass heads, so is the ZS4.
    It pushes, punches properly and also goes very deep. However, it's a bit too much for me, because the bass is very pronounced especially in the middle/upper range. This also leads to the blending of the mids. You can't expect great details here, it depends more on the quantity.

    The mids are a bit shy, especially when it comes to very bass-heavy songs. This is especially noticeable in male voices, which seem more distanced. That's a shame on the one hand, because they have something on their chest, but can only play out their potential with less bass intensive music. An equalizer certainly helps here if you want to lure them out a bit. They do have an appealing level of detail and, if you allow it, a good separation. The upper mids can sometimes get a little hard and so unpleasant in some songs.

    The same applies to the highs, which are more of the brighter kind (quite contrary to the ZS3), have a good resolution and offer a lot of details, but also sting here and there and highlight the sibilants.

    I see the ZS4 clearly above the ZS3 and just as easily above the ES3, but for my taste you get more for your money with the ZSA, ES4, or ED16|ZS7, even with the ZST Pro. They're not bad and especially made for bass lovers and electro|EDM fans, but for many other genres you should have an equalizer at hand if you're not into full bass and treble sensitive, and want to emphasize the actually very good mids.

    KZ doesn't give in to the ZS4's nakedness and produces a good hybrid, albeit with some limitations. Only the product name suggests something different, since KZ has already delivered better in the price range and in the dual configuration (1*DD & 1*BA).

    More reviews: https://david-hahn.wixsite.com/chi-fiear
    Facebook: https://www.facebook.com/CHIFIEAR/

    You can find it here: https://www.amazon.com/dp/B07GGQCSG6
      williamclarkonet and momo8023 like this.
    1. momo8023
      Hello, how is the comfort of wearing?
      momo8023, Dec 12, 2018
    2. DallaPo
      In my opinion they are a bit bulky, but very ergonomic due to their design. There are definitely more comfortable in-ears.
      DallaPo, Dec 13, 2018
    3. Kressel
      Great comfort. Put some foam ear tips and it helps tame the harsh high mids and it tightened the bass. I use the vsonics ear tips and I'm happy.
      Kressel, Dec 19, 2018


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