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  1. Zelda
    KZ ES3 - Review
    Written by Zelda
    Published Jun 20, 2018
    Pros - Fun sound with good quality; Price; 2-pin detachable cable
    Cons - Earpieces can be a bit large for some

    es3 (1).jpg

    • Driver(s): Hybrid setup, 1xBalanced Armature + 1xDynamic
    • Impedance: 10ohm
    • Sensitivity: 106db
    • Frequency Response: 20 Hz - 40 Khz

    Price: U$D 15~20, and sometimes can be found for just $10.

    Upgrade cable: U$D ~9.

    The package is as simple it gets, with just 3 pairs of the KZ style eartips and the 0.75 2-pin detachable, everything inside a compact white box. It’s hard to ask for any extras at this price point.

    es3 (2).jpg


    The ES3 shells are made entirely of plastic material, with a semi-translucent shell that allows to see the inner drivers’ configuration, which is cool to have on these low budget options. Like others KZ IEMs the ES3 also utilizes the 2-pin detachable cable feature. They’ve a less standard connectors of 0.75mm instead of the more common 0.78, but KZ already has an upgrade cable and a few others can be bought at a low price as well. The connection is quite good, much better than any standard MMCX option.

    The ES3 design adopts a strictly over-ear fit with a semi-custom look. Despite the simple 1BA + 1D setup, the earpieces are not exactly small and could be too large for smaller ears. Nonetheless, they have a comfortable smooth fit with nice level of isolation.

    The included cable is very average and carries some noise effect. It has a fixed memory wire and it’s terminated on a standard L-shaped plug that reminds of the last Vsonic plug and y-split, with a slight rubbery coating.

    As for the upgrade cable, it not only looks much better, but also improves the fit and lowers the cable noise. It’s a 4-wire twisted silver-plated copper cable. It has the same memory wire, plug and y-split section as the stock cable and still lacks the slider. It’s worth noting that there’re two options for the upgrade cable, which simply differentiate in the 2-pin outer shape, straight or angled, which will depend on the KZ or other IEM it may be needed for.

    cable (2).jpg

    cable (1).jpg


    As could be expected, the KZ ES3 presents the common friendly signature with a bit of V-shaped response. There's a strong amount of bass with more dominant mid bass emphasis and fairly extended and deep sub-bass. Quality, texture and speed is more than decent at this very low budget price, with a nice fun factor overall without being overwhelming. It may get loose a bit and out of control on heavy bass or more complex tracks but still the low end is enjoyable.

    While the midrange remains under the lively signature with strong bass and treble, it is not a very pronounced v-shaped presentation. It’s more due the powerful low-end that makes the lower midrange region less forward. However it contributes in giving a fuller and more engaging presentation. The tonality is towards the warmer side, it still sounds quite musical and not too congested. Upper mids sound clearer thanks to the extra energy from the lower treble, carrying a good level of detail and texture for female vocals; if anything they can sound a bit dry and are not sibilance free, but some tip-rolling may help.

    The treble is well balanced with lows, sparkly, energetic and a bit rough or lacking in control. The focus is more towards the lower treble, and extension can be a bit limited (more than acceptable at this price point). Upper instruments can be a bit exaggerated, but the overall separation is good enough.

    The soundstage is average to small, compared to something like the VSD2 or A&D D2 options, or the own company ZS5 and ZS6 models, and around the same dimension of the Fiio F3. However, the overall level of detail is surprisingly good.
      DocHoliday and B9Scrambler like this.
  2. DocHoliday
    What hast thou wrought?
    Written by DocHoliday
    Published Mar 9, 2018
    Pros - Comfortable fit and seal
    Detachable cables
    Nicely weighted bass for EDM
    Fatigue-free treble
    Lover'ly midrange
    More soundstage depth
    Cons - Quality Control issues
    Pick your poison!


    What are you willing to live with and what are you willing to compromise on in order to get more of what you want most?


    ....and what is a reasonable pricepoint for a fatigue-free IEM WITH detachable cables that provides healthy proportions of all of the above?

    I suppose the real question is "What has KZ wrought with the ES3?"

    I received my first set of ES3's back in November 2017 but they were faulty and needed to be replaced. Fortunately, George at GearBest provided me with an ES3 sample so I could do a proper review and determine how well the ES3 performs in comparison to the growing sea of sub-$30 Chi-Fi IEMs.

    GearBest currently carries the KZ ES3 at the lowest price I've seen, which is $14.99.

    Since we're on the subject, a huge thanks to George at GearBest for providing the sample.

    Full disclosure:
    I've no affiliation with GearBest and receive no remuneration for the review other than retaining the review sample.

    Before we get started on the review of Knowledge Zenith's ES3 you should know upfront that I own and enjoy each of KZ's hybrid IEMs [ZST, ZSR, ZS6 and ZS5(i)] and I have no issue with the treble present in any of the four models. I mention this because those of you who are sensitive to forward treble would be wise to keep in mind my preferences and properly absorb this review through the filter of your own preferences.

    About me:
    I tend to prefer a relatively neutral sound signature with a slight emphasis in both bass and lower treble, which is basically a mild "U" shaped sound signature where midrange frequencies are left intact and unaffected. I find that an absolute neutral sound signature usually lacks enough energy for the genres I enjoy most, which are Classic Trance and Progressive (early Tiesto, Markus Schulz, Otello, DT8 Project), Chill Out, Breakbeat (Hybrid & Burufunk Remixes) and 80's & 90's (New Order, Secession, The Cure, Siouxie & The Banshees, Depeche Mode). Sure I listen to Verve, Verve Remixed, Sade, Bach, Ella Fitzgerald and everything in between, but as of late the bulk of my listening pleasure is focused on the aforementioned genres.

    About IEMs:
    Take note when you read IEM reviews that when the reviewer gives his/her opinion regarding the sound that there are many factors that shape the final sound an IEM delivers to one's ear.

    Those factors include:
    1 - Shape & size of reviewer's ear canals. (shallow/deep, wide/narrow)
    2 - Shape & size of eartips (round/cone, single, double or triple flange)
    3 - Materials of eartips (silicone/foam)
    4 - Shape of IEM (and/or angle of nozzle) can cause fitment issues for some.
    5 - Source (quality of DAC in smartphone, laptop, digital audio player)
    6 - Source (power rating) is it amplified/unamplified.
    7 - The IEM itself (driver flex/trapping air in canal causing muffled sound.
    8 - The Reviewers ability to hear all frequency ranges (age plays a factor).

    Most consumers are unaware of how much weight each of these factors hold in rendering a final verdict. This is why there is such a wide variance in not only ratings, but the description of an IEMs sound. An unaware consumer purchases a perfectly fine IEM but has difficulty keeping the IEM in the ear or he/she does not satisfactorily seal the ear canal with the included silicone eartips (this is a common occurrence) and the consumer summarily dismisses the IEM as sub par. Another consumer purchases the same IEM but experiences a perfect fit and seal and has nothing but praise for the same IEM. Sealing the ear canals AND HAVING THE EARTIP FIRMLY AFFIXED to the IEM nozzle is the only proper way to use in-ear monitors. I can think of no audio equipment that is subjected to such praise or ridicule as the in-ear monitor. As if that's not enough, there is no "one-size-fits-all" when it comes to IEM eartips.

    Materials (silicone/foam) have different dampening effects on final sound.
    Shape of the eartips (olive-shaped, cone-shaped or other-shaped) can have different dampening effects on final sound based on how much space is between the IEM nozzle and your eardrum and how well the eartip has sealed the ear canal.
    The aperture of the eartip's opening (wide-bore/narrow-bore) will have dampening effects on the final sound.

    The easiest way for you to experience the different effects I am discussing is to take your current on-ear earphones or over-ear earphones, pick a song full of energy, put the earphones on and let them sit naturally over or on your ears. Listen to the music for two minutes. After two minutes, using your hands, slightly press the headphones closer to your eardrums. Notice the change in the sound. Is there more/less bass? Is there more/less treble? Did the vocals slightly slip forward/back?

    Consider that on-ear and over-ear headphones have a driver that sits approximately 1 1/2 inches to 2 inches from your eardrums and by pressing the headphones 1/4" closer to your eardrums the sound changed. Now consider that an IEM driver sits anywhere from 3/4" to 1/4" from your eardrums and the slightest changes (angle, depth, shape, material) can have up to three times more of an effect due to the proximity of the IEM to the eardrum.

    For this reason, I think it is wise to invest a nominal dollar amount on different eartips to find an eartip that works well for your particular ear's anatomy. This way you experience everything the earphone tuner intended for you to experience. Some IEM manufacturers supply multiple sizes (S/M/L) and/or materials (silicone/foam) of eartips to increase the odds that the consumer achieves a satisfactory seal, but even this is not foolproof. If this information holds any interest for you, there are a plethora of aftermarket eartip brands to look into, such as "JVC Spiral Dots", "Spinfits", "Comply Foam Eartips" or "Znari Foam Eartips", "Creative Aurvana" and others. If you really want to fine tune things, then you might find yourself doing what I do, which is scouring Amazon or AliExpress for inexpensive earphones that appear to have silicone eartips that have a shape that typically work well with my ear's anatomy.

    2018-03-08 23.54.56.jpg
    The Knowledge Zenith ES3:

    Upon hearing about the release of KZ's newly released ES3 I suspected KZ would address, in my opinion, the minor flaw of their ZST model. That minor flaw is a slight loss of warmth in the lower midrange. The treble sensitive consumer would argue that the ZST is a bit bright but I don't find the ZST to be aggressive in the treble region unless I have adjusted to the sound signature of an excessively warm IEM just prior to using the ZST.

    As usual with KZ, the packaging is as basic as it gets so there's no need to spend time on it. It is standard KZ fare that includes a basic cable (with memory wire) and KZ's proprietary Star-tipped silicone eartips (one of my favorite eartips). It's easy to start mumbling about the sparse packaging but considering what's on offer here plus the fact that I get even more of KZ's proprietary Star-tipped eartips means I'll just.......button my lip.

    The ES3 is quite comfortable for me; I like that they are light, have no sharp edges or corners and that the ES3 nozzle will accommodate my unhealthy penchant for tip-rolling. Be aware that I rarely comment on comfort because ears are like fingerprints.....they're all different.

    I find the ES3 to be a perfect companion for listening to EDM due to the ES3's more visceral kick in the lower frequencies and the slight haircut in the upper-treble. The fact that the midrange can hold up well with those ingredients means your ears are in for quite a treat.

    The ES3, while more dynamic than the ZS3 but less technical than the ZS6, has not been without a bit of controversy. Apparently, there seems to have been a spate of quality control issues for the ES3 with things such as vents obstructed with glue and resonance issues originating from the use of foam as a dampening agent. My first pair of ES3's suffered from the latter issue.

    We have an invaluable member over on our beloved KZ thread that reports on frequency response and impedance specifics for any given KZ in-ear monitor we are discussing on the thread and he posted some interesting test results that showed a slight variance in sub-bass and mid-bass levels, which effected the midrange as well. Apparently, the variance was due to glue obstructing the ports/vents on one or some earpieces and not on others.

    2018-03-09 00.08.30.jpg
    At any rate, it appears my suspicions regarding the ES3 sound signature have been confirmed. The ES3 sounds like a ZST with three slight modifications.

    The three modifications are:

    The ES3 has improved body and warmth in both the upper and lower midrange. The improvement in the midrange contributes to a more full-bodied signature as opposed to the ZST's sense of air and lightness. The ZST is a phenomenal IEM for $20 but the ES3 is no slouch. It improves not only overall texture in the midrange but the ES3 also improves the depth of the soundstage.

    Take a listen to the following tracks paying particular attention to the lover'ly weight in the lower-midrange and the vividness of the vocals in the upper-midrange.

    This particular modification will be a welcome adjustment for those who prefer a warmer sound signature or find themselves to be treble sensitive. The treble on the ES3 is slightly rolled so there is more focus on lower-treble and mid-treble. Micro-details and upper treble are still present but delivered with a smoother presentation allowing for fatigue free listening sessions. You can literally listen to the ES3 for hours on end.

    The following tracks have a bit of energy up top so pay particular attention to how much detail is displayed despite the ES3's ultimate goal of taking the edge off for comfort and fatigue-free sessions.

    The bass of the ES3 is somewhat soft with deep reserves and has slightly more presence than the ZST's faster and cleaner bass. In fact, I wonder if Knowledge Zenith designated the "ES3" moniker because the ES3 sounds like a ZS3 with improved dynamics across the board: the most notable improvements being soundstage depth and width while improving resolution. The ES3's presentation and sound signature pair well with Progressive House, Chill Out and other EDM genres. If you own KZ's ZSR you will immediately notice the the ES3's lack of the midrange balanced armature found in the ZSR. The ZSR's additional midrange gives it the more mature presentation with more midrange depth when comparing the two IEMs and in my opinion the 50% markup in price for the ZSR is money well spent. Having said that, the ES3 is still an IEM worthy of your attention because it may well outperform much of the competition at the sub-$50 price point.

    Even more enticing is the fact that the ES3 scales quite well with more juice because the lower half of the frequency spectrum lends more weight/body to the sound signature. I suppose whether or not you like the added oomph is a matter of preference or even a matter of pairing (source), but the ES3 paired well with my Fiio X3(i). In particular the bass region definitely had more kick.

    The following tracks will have the ES3 performing like no $20 IEM should legally be allowed to perform. Note the weight of the mid-bass in "Starlight" and "My Own Worst Enemy". Then there's that sub-bass. Check it out on "Guittara G" and really every track listed here and above, especially Delerium's "After All". The ES3 sounds exceptional, rendering every track with a detailed but soft energy with an admirable low end thunderous boom and "slow, but lover'ly" decay.

    Soundstage on the ES3 is above average in width and, as I noted earlier, has improved depth when compared to the ZST. If you listen to the ES3 directly on the heels of listening to the ZST you could easily claim that the former sounds a bit congested in comparison, but I think it's just the nature of adding more weight and tuning the ES3 to be fatigue-free, so to speak. Again, KZ appears to have released the ES3 to cater to those who find the ZST just a bit too edgy up top. Despite KZ's foibles and flaws you have to tip your hat to them for listening to their fans, for the most part, and addressing issues regarding sound signature. It's probably why we have a "love/.. errrr dislike relationship with KZ. We accept their flaws as we journey along with them.

    At this very moment I'm not sure which of the two IEMs I prefer more. The differences are noticeable. I suppose the ZST presentation is a bit more airy while the ES3 is a bit more full-bodied.
    2018-03-08 23.46.42.jpg

    I'll summarize my findings with following:
    The ES3 is your pick if you are treble sensitive or prefer a smoother presentation with deeper yet softer bass.
    The ZST is your pick if you think you'd be one to miss the more defined micro-details or if you prefer cleaner, faster bass.
    The ES3 will be slightly more forgiving with less than stellar production recordings with treble spikes due to the slight roll-off in the treble, but be mindful that the sword cuts both ways because the bass presentation in a less than stellar production recording may suffer on the ES3, while the ZST would do a better job presenting said bass.

    In the end you have to decide what works best for your music tastes.


    Just pick up both the ES3 and the ZST. That's only about $40+/- total.
    Knowledge Zenith makes it really hard to resist getting both with their unbeatable price structure.

    Yes, the ZS6 is more accomplished and yes the ZSR has a better handle on dynamics, but it's all in the family and sibling rivalry is present in every household. When I listen to the ZS6, ZSR and ES3 back to back in that particular order I notice what I'll call the missing link. Going from the ZS6 and it's four drivers to the ZSR and it's three drivers I immediately notice the loss of the ZS6's midrange driver and the defintion it brings to the midrange. When going from the ZSR to the ES3 I immediately notice the loss of the ZSR's midrange BA and the weight it lends to the midrange. At $45+/-, $30+/- & $20+/-, respectively, you can clearly hear the upgrade or scalability if you will. When you consider that all three IEMs have detachable cables and cost a total of $100+/- for the lot.....well....let's just say it's a great time to be alive.

    Bottom line: the ES3 shouldn't be overlooked.

    So, what has KZ wrought?
    ES3 -2.jpg
    Another great set of inexpensive in-ears for my ears and my collection.

    Thanks again KZ!

    The KZ ES3 is currently available at GearBest.com for $14.99.

    p.s. - now if I can only find a cable that will do the IEM aesthetic justice

    *** update ***
    great upgrade cable to do the ES3 justice.
    1. View previous replies...
    2. DocHoliday
      Thanks B9! There is a bit more info that I'll be editing into the review that you should be aware of, mostly related to hakuzen's findings and my own experiences. It's a result of their QC.......once again.
      DocHoliday, Mar 9, 2018
      B9Scrambler likes this.
    3. mrmoto050
      Great review, I just ordered both, curious how they will sound to me.
      mrmoto050, Mar 9, 2018
      Strat Rider and DocHoliday like this.
    4. hakuzen
      awesome work, Doc!
      hakuzen, Mar 11, 2018
      DocHoliday likes this.