KZ Zs6

New version is basically an upgraded version of the old ZS6s.
Less treble fatigue, better balance overall.
Not worth $50 in today's market.

A brief journey into the world of Chi-Fi.

For those of you that are unaware, there is a quiet storm taking place in the IEM (and Audio Gear) market which we hobbyists affectionately refer to as Chi-Fi (Chinese Fidelity). In essence, the sound quality of audio gear coming from some Chinese manufacturers (Knowledge Zenith, Fiio, Monoprice, Shanling and others) is improving and progressing at a quickening pace. Some brands deserve as much attention as the established brands, if for no other reason than the value proposition in what is quickly becoming an unavoidable global economic downturn (where one typically receives less for their hard earned cash). In the midst of said global economic upheaval, KZ Acoustics is a manufacturer that consistently offers exceptional value for your hard earned cash and the ZS6 is evidence enough that the changes in the world of audio gear are reaching a feverish pitch.

Before we get into the review you should know upfront that I own and enjoy several of KZ's hybrid IEMs (ZST, ES3, ZS5(v1) & ZSR) and I have no issue with the treble present in any of these models. I am a micro-detail junkie that enjoys a bright sound signature IF......IF there is enough weight and density present in the midrange and lower extremities. 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:

About IEMs:

The Knowledge Zenith ZS6:

When Knowledge Zenith released their single dynamic driver ZS3 "with detachable cables" in June 2016, there wasn't much in the sub-$20 category that could touch it's sound quality and comfort (so long as you knew how to moderate the bass response via eartip size).

Several months later KZ ventured into the hybrid market offering their impressive and well received budget-friendly ZST (a 1BA & 1DD model with detachable cables) which, at the time of it's release, nearly dwarfed everything else in the sub-$20 price bracket.

All of Knowledge Zenith's earlier models (ED3, ED7, ED8, ED9, ED10, EDSE, EDR1, EDR2, ATE, ATR, HDS1, HDS2, HDS3, DT5, DT3 and others) were dynamic driver IEMs in the sub-$20 price bracket and several of these models deserve your attention if the ZS6 at $48 is too steep for your budget at this particular time. I have included links to several reviews of said models here on Head-Fi that can help paint a clearer picture of a KZ in-ear monitor that might cater more to your particular preferences.


KZ In-Ear Monitors:

B9's blog - The Contraptionist (required reading for the unintiated)!
https://thecontraptionist.blog/category/knowledge-zenith/

EDR1 - https://www.head-fi.org/showcase/knowledge-zenith-edr1-in-ear-monitor.22987/
EDR2 - https://www.amazon.com/review/RWFUWN0QH5ZP1
ED3 "Perfection" - https://www.head-fi.org/showcase/knowledge-zenith-ed3-perfection.22988/
ED3 "Acme" - XXX
ED4 - https://www.head-fi.org/showcase/knowledge-zenith-ed4.21296/reviews
ED7 - https://www.head-fi.org/showcase/knowledge-zenith-ed7-in-ear-monitor.23035/reviews
ED8 - XXX
ED9 - https://www.head-fi.org/showcase/kz-ed9-tunning-nozzles-in-ear-headphones.20807/
ED10 - https://www.head-fi.org/showcase/knowledge-zenith-ed10.22990/
ED15 - XXX
ED16 - https://www.head-fi.org/showcase/kz-ed16.23179/
ES3 - https://www.head-fi.org/showcase/knowledge-zenith-es3.22976/
ES4 - https://www.head-fi.org/showcase/kz-es4.23181/reviews
HDS3 - https://www.head-fi.org/showcase/knowledge-zenith-hds3.23017/
https://www.amazon.com/gp/aw/review/B01EJHLOPE/R7E4KEB1RJ88Y?ref=pf_ov_at_pdctrvw_srp
ATR - https://www.head-fi.org/showcase/knowledge-zenith-atr-in-ear-monitor.23032/reviews
ATE - https://www.head-fi.org/showcase/kz-ate-in-ear-monitors.21174/
HDS1 - https://www.head-fi.org/showcase/bi...ic-pronunciation-ear-headphones-silver.21143/
ZSA - https://www.head-fi.org/showcase/kz-zsa.23180/reviews#review-20770
ZST - https://www.head-fi.org/showcase/kz-zst.22435/
ZSR - https://www.head-fi.org/showcase/kz-zsr.22905/
ZS3 - https://www.head-fi.org/showcase/kz...et-bass-earbuds-with-microphone.21763/reviews
ZS5 - https://www.head-fi.org/showcase/knowledge-zenith-zs5.22479/
ZS10 - https://www.head-fi.org/showcase/kz-zs10.23034/
AS10 - https://www.head-fi.org/showcase/knowledge-zenith-as10.23246/reviews
BA10 - XXX

KZ Acoustics is the trailblazer; they lead the way on what can be achieved by pushing the envelope in price-to-performance offerings.
In this instance KZ Acoustics is the first manufacturer to market with a quad-driver in-ear monitor below not just the $200 threshold or even the $100 threshold. No KZ has offered the ZS6 at below the $50 threshold.



The ZS6 is a dual dynamic driver (10mm & 6mm) AND dual balanced armature hybrid in-ear monitor for. $45+/-!

You read that correctly; $45 for a 2+2 hybrid IEM!

Prior to the ZS6's release (actually the ZS5's release) the minimum entry fee for a quad-driver was $200 (1More Quad-Driver) but KZ's ZS5 and ZS6 opened the floodgates. Now the marketplace is awash with sub-$50 quad-driver IEMs from a growing number of manufacturers that are planting their stake in the ground in hopes of establishing a name for themselves. That's all well and good but my suggestion is that we take a moment to reflect on which company actually cast off the shackles of conventional thinking to bring you far better sound at a far better price.

Still, looking back at KZ's previous offerings $50 is quite a jump in price from $20 and it just begs the question:

"Should Knowledge Zenith be venturing into deeper waters?"

Sure, they've churned out dozens of great sounding single dynamic driver IEMs and several dual dynamic driver IEMs but is it somewhat optimistic of KZ to include their wares in higher IEM tiers or should Knowledge Zenith just continue doing what they've proven to do better than just about any other budget IEM manufacturer, which is to CONSISTENTLY offer the best "bang for buck" IEMs in a landscape littered with "hit or miss" budget-fi IEMs from East Asia?



Let's start at the beginning and take into consideration that the ZS5 was KZ's very first budget-minded 2+2 hybrid IEM to hit the market. As a devoted fan of Knowledge Zenith, I won't hesitate to tell you that I was notably disappointed that KZ offered their flagship model (ZS5) in a PLASTIC shell. It later became clear to me that the ZS5 was more likely a beta model; a stepping stone to the beautifully crafted and rich sounding ZS6.

Yes, the ZS5 and ZS6 shells may enclose similar hardware but to my ears they offer very different presentations. A 2+2 hybrid design is a much more complex endeavor than KZ's more simple 1+1 hybrid design (ZST) and one wonders if the sound engineers at KZ have the skills to properly tune such a complex design? A good number of dual dynamic driver IEMs have earned the reputation of sounding .......well, muddy; meanwhile many hybrid IEMs have earned a reputation of sounding somewhat incoherent due to two completely different technologies at work yet sharing the same space. Is KZ capable of bucking the trend? If the answer to that question is no then this could go very badly for KZ. Most of KZ's detractors and even KZ's fans would quip hat KZ should stick to the $10 budget bin and if the answer to that question is yes then the more logical question is "will more drivers automatically equate to better sound?" Let's find out just what the mad scientists at KZ Acoustics have been up to.

ZS6 Housing:
My Rose Red ZS6 has a beautifully crafted CNC aluminum casing with a full aluminum nozzle (no signs of cheap plastic). The faceplate of the ZS6 has three vents and a quality mesh grill just beneath said vents to keep dust and grime from getting in whilst allowing the music to breathe. The three torx screws that affix the faceplate to the main body allow easy access to the ZS6 inner components if I need access to them. It's all very well done!

I wholeheartedly applaud KZ for including the option for easy access because it allows me to experiment with different modifications. I have considered opening one of my ZS6's to reposition the BAs so they fire into the main cavity of the ZS6 instead of firing directly out of the nozzle. I'm hoping this might temper extension and perhaps soften the analytical nature of the BAs while increasing soundstage via diffusion and reflection of the treble. We'll see, right?

Later, we'll take a look at an actual modified ZS6 by the KZ Thread's very own "Slater", so the treble-sensitive among you should find that informative and helpful.

Detachable Cables:
I am particularly disappointed in KZ's choice of cable for what was once their flagship IEM. The included cable was specifically designed for the KZ ZS3. I saw fit to upgrade the fable on my ZS3. What on earth was KZ thinking in offering something so pedestrian with something as polished and upscale as the ZS6? Note the angled step down moulding below the "L" & "R" markings on the cable connectors. Those angles were designed specifically for the KZ ZS3. At any rate, I recommend KZ's Braided Silver Upgrade Cable (4-core transparent) with the 3.5mm jack or the 8-core Braided Silver Upgrade Cable that you see attached to my ZS6. I will give credit where credit is due by saying kudos to KZ for choosing to stick with the 2-pin cable design instead of the MMCX cable design. MMCX cables may be more common but I believe the 2-pin design is a more reliable connection less prone to interruption as MMCX connections can sometimes deteriorate.

Eartips:
The ZS6 comes with KZ's exclusive Star-tipped Silicone Eartips (S,M & L) which affix firmly to the ZS6's aluminum nozzle but be aware that earlier models of the ZS6 have no lip to keep the eartip from sliding off. A Q-Tip and a pinch of hydrogen peroxide can be employed from time to time to dissolve the earwax that tends to cause slippage.

There has been much praise of the ZS6 sound signature when the ZS6 is paired with foam eartips. I have Znari Foam Eartips and Comply Foam Eartips but I just can not abide the dampening effects present in foam eartips because I always feel one step removed from the music. Don't let my preferences deter you because many people find foam eartips to be a much more comfortable fit. In fact, many people prefer the foam eartip's ability to smooth out the analytical and sometimes cold nature of balanced armature receivers. Indeed, many people swear by foamies and use them exclusively but to my shallow ear canals their is a slight loss of definition to everything portrayed from top to bottom (bass, vocals, treble, etc.). In other words, for me, foamies smooth things a little too much. Instruments and vocals tend to lose their etched definition by a slight degree and for me that slight loss is unacceptable because an instruments definition needs to be true to a fault. Conversely, silicone eartips ALWAYS give me a presentation that I deem "true" to the music and "true" to the IEM. To my ears, the best silicone eartips for the ZS6 are KZ or Tennmak Whirlwind eartips but said eartips are not included. In light of its near $50 pricetag, KZ should be including their own Whirlwind eartips (S, M & L) with the ZS6. In fact, I'll go one step further and say that KZ should be including three variants (Star-tipped, Foam and Whirlwind) to give the consumer an optimal chance for a satisfactory experience with their flagship IEM.

Pairing:
My general rule of thumb when it comes to IEMs that sport multi balanced armatures is to use a low output impedance source with a well regarded DAC and sufficient power. Though the impedance of the ZS6 is 16Ω it still sports not one, but two balanced armatures and two dynamic drivers (6mm & 10mm)

Having multiple balanced armatures can sometimes introduce impedance curves and/or render an IEM quite sensitive to your source (phone, laptop, DAP, etc) so keep in mind that if your main source is a power-efficient smartphone you may find the ZS6 to be quite bright. If your phone isn't tethered to a low impedance portable amp or equipped with an exceptional DAC then a single dynamic driver IEM like KZ's ZS3 (warm), EDR2 (more balanced) or ED9 (bright and airy) may be a better combination/pairing with your phone. I suspect that a fair share of the complaints of an unpleasant treble spike on the ZS6 may be due to ill pairings. You'll get the best out of the ZS6 when it is paired with a warm-leaning DAP. You will also find that a great DAC and more power will likely give you a smoother response. It's not a hard and fast rule, but I find it to be true more often than not.

SOUND:

I would describe the ZS6 in stock form as an IEM that excels at presenting micro-details and definition in treble, midrange (vocals) and bass all at once. You will hear "everything" that was recorded and you'll hear it in HD! A poorly mastered track will be shamefully exposed while a well mastered track will sound incredible.



I made a minor modification to my ZS6. I removed the red nylon screens from my KZ ZS3 and centered them directly on top of the ZS6 metal screens. This softened the analytical nature of the BAs giving my ZS6 a sound signature reminiscent of a well-tuned single dynamic driver. Instead of being full-bodied in the lower frequencies and highly analytical in the higher frequencies the coherency was astounding from top to bottom because the "body" of sound was uniform from 16hz - 16,000hz (my hearing range). I sampled the ZS6 for 6 uninterrupted hours with various genres .....zero fatigue!

Let's isolate and address the more substantive frequency ranges.

Bass:
To put it succinctly, the ZS6's bass is clean, tight and natural with admirable texture in both mid-bass and sub-bass.

No bleed.
No bloat.
......yet quite authoritative.

The balance of sub-bass to mid-bass is well-judged at nearly 50/50. The music was flowing and alive regardless of the genre I listened to.

My best description would be a velvet hammer because the bass hits hard but doesn't obscure the other frequencies. Typically, big bass can mask higher frequencies and/or force the midrange into submission but this is not an issue for the ZS6. When pairing the ZS6 with Tennmak's whirlwind wide-bored eartips I thought the lower frequencies might lose some impact due to diffusion but they still came through with excellent presence and weight. You need to hear how resolving and clean the sub-bass is?
It's hauntingly flawless on demanding tracks like Solarstone's take on "Center Of The Sun".



Want to hear how deep your ZS6 will dig? Push play on "Imagine" below and be amazed. I should mention that on my smartphone the track's bass is deep but slightly loose; on my Fiio X3(i) it is exceptionally clean and deep.



For composure, let's test two tracks. The first is a recording of an epic metal track that had only mediocre mastering. The drums are in double time but you can still pinpoint both lead guitars chugging away separately. The second track has better mastering (superior separation and imaging) but the ZS6 possesses the ability to cleanly pull and separate the details on the first track with no loss of composure in the presentation.....despite the mediocre mastering.



Why am I so enamored?

The ZS6 is only $40+/-!

Bass: 9/10

Midrange:

The first track to showcase the ZS6's midrange is Tracy Chapman's remastered "Fast Car". Remastered tracks aren't always "better" but the 2015 remastered "Fast Car" sounds much more dynamic than the standard recording. The ZS6 neatly unpacked everything and put it all on the stage in my mind's eye . Tracy's vocals are forward, full-bodied and alive, refusing to be subdued by the copious bass.

James Taylor's "Fire and Rain" was just as vivid with great texture, presence and clarity. There were moments that I thought I might be hearing resonance but it turned out to be the cello's natural resonance rendered exceptionally well. It was lifelike; it was mesmerizing.



What about classical music?

It's a great compliment when I say that I felt as though I was at Symphony Hall witnessing Rudolf Serkin and George Szell make history recording one of Brahms' more complex piano concertos. The ZS6 captures the weight of the notes from the piano and the timbre of the french horns quite well.



J.S. Bach's Toccata & Fugue in D minor (BWV 565) is another perennial favorite but the ZS6's transparency will expose that the first sample lacks the depth of emotion found in the second sample. I absolutely despise the way the first sample was mastered but it is one of the clearest recordings I could find on YouTube that would serve our purposes here. You will hear how clumsy the recording engineer is. He completely butcher's the timing and flow of the orchestra by carelessly introducing strings and other instruments in a slipshod manner. For instance, between the 25 sec and 35 sec mark the Timpani/KettleDrum should steadily rise drawing you in just as the piece begins to unfold; the rolling of the timpani should evoke a strong sense of emotion here.....but it was not to be with this recording and the ZS6 lays it bare. Likewise, the outro of the introduction from 3 min 12 sec mark to the 3 min 30 sec mark the timpani/kettledrum should steadily rise and evoke a strong sense of emotion........but it does not.



Now, hear a proper recording of the same piece. From the outset you are drawn in and willingly held captive until the piece closes. The ZS6 sets the table neatly so you can focus on the feast set before you.


The ZS6 presentation is clean enough that it affords one the ability to hear the slightest nuances of a given recording. Plainly stated, I loathe the former sample and champion the latter.

Moving on, can there be intimacy in a more complex metal track?

Yes, but metal recordings tend to range from cacophony to sublime perfection.

It's real and present with FlyLeaf's ode to being alive in "All Around Me". Sturm's vocal range and coloration is well suited for folk or bluegrass genres but through the ZS6 you can hear how she pulls no punches here. There is good presence and decent weight but the ZS6 shows how the vocals go form slightly recessed to slightly forward during the recording.



Midrange: 9/10



Treble:
This is the section that the treble-sensitive are positively raising hell over. Some simply can't handle it.The ZS6 treble focus is on lower-treble to mid-treble. It is forward though not sibilant to my ears. On some tracks like Toni Braxton's "He Wasn't Man Enough For Me" the treble was a bit aggressive and I had to turn the volume down a couple of notches but the sense of air and transparency is exceptional. If you are treble-sensitive you should probably skip this sample because the recording is exceptionally clear with a fair amount of energy up top and the ZS6 delivers it with open arms.



If you just listened to the above track and it was a bit too much for you then please be aware that it is common practice to wear foam eartips with hybrid or balanced armature IEMs to soften the BA's analytical nature. This is not something that is applicable to one manufacturer, it is common practice when using BA in-ear monitors. Most of you should be considering foam eartips for the ZS6 because, again, you'll find that foam eartips will absorb the occasional aggressiveness on some of the recordings in your music collection.

Diana Krall's "I Miss You So" and "Maybe You'll Be There" are tracks that are prone to sibilance but I experienced none with the ZS6. Both tracks were presented with excellent micro-detail while the midrange seemed almost forward in the mix. The treble does not overpower the midrange. The presence of Krall's voice has your full attention.



Treble: 8.5/10

Before moving on I think it would be wise to point out the ZS6's unforgiving nature. Sometimes recordings are mastered with shouty and unrefined vocals and consequently the presentation of such recordings can be somewhat of a mixed bag. You may not enjoy the end result if you couple the ZS6 to a bright-leaning DAP in the hopes of enjoying recordingsthat display scratchy or strident vocals. The upper-midrange will be somewhat raw and unrefined because the recording is somewhat raw and unrefined.

To put things into perspectiveI'be included several samples of what to avoid with the ZS6. You'll hear the flaws.



It's really a pity when you consider that recordings of this caliber were recorded nearly 40 years earlier. 40 YEARS!




Soundstage and Imaging:

The previous 2+2 model, the ZS5(v1), sound airy and detailed with a wide soundstage. The ZS6 soundstage is slightly different. The ZS5(v1) soundstage is more linear from left to right. I wouldn't say the ZS6 soundstage is more narrow, it actually has a different shape and is more diffuse. I find that the midrange on the ZS6 sits a bit more forward giving the ZS6 soundstage more of a "V" shape. On the ZS5, the details that are on the periphery are as prominent as the vocals. On the ZS6, those same peripheral details slip back slightly. Yes, those details are still there; they just aren't as prominent because the midrange/vocals are more present. With the ZS5 you are on stage with the band. With the ZS6 you are in the front row with the lead singer reaching for your hand while the band is just a few short feet away.

I should mention that my Fiio X3i does not have an equalizer. The Fiio X3i has a 10+/- treble adjustment and a 10+/- Bass adjustment. I don't like altering the sound via EQs but I did modify my ZS6 ..... with the ZS3 nylon screens. I bring all of this up because when I paired the blue whirlwind eartips you see in the photos with my screen modification, not only were the highs gently attenuated, but the soundstage widened a tad and the overall sound in general was a bit more cohesive. I would go so far as to say that my ZS6 does not sound like two different technologies (dynamic driver & balanced armature) at work, but rather a well tuned Dynamic Driver with a coherent and consistent body from top to bottom (16hz to 16,000hz) as opposed to the DD sounding full bodied and the BA sounding analytical. I find that my modification doesn't alter the sound exiting the source (Fiio X3i) but it redirects sound, via reflection, around the filters (nylon screens) resulting in a slightly wider soundstage. In my estimation the ZS6 is an in-ear version of the Superlux 668b over-ear full-size headphones, albeit with slightly more presence in the lower frequencies. That is quite a compliment in my book.

Comparison to the ZS5:
The ZS5(v1) is an epic IEM for $36, and although few IEMs in the sub-$40 price bracket could touch it at the time of its release, the lack of presence in the mids, it's dual personality (due to the lack of a crossover) and the secondhand cable shenanigans (square peg in a round hole) kept the ZS5 from being all it could have been. If you've read my ZS5 review, then you know that I considered the ZS5 to be a beta project for the ZS6. That said, most of its shortcomings have been addressed and rectified with the release of the ZS6.

In my opinion those shortcomings were:
The ZS5's plastic housing (the ZS6 is beautifully crafted aluminum)
Nonexistent crossover (the ZS6 has an active crossover)
Mids (ZS6 = creamy and present vs ZS5 = laid back and slightly recessed)
Bass (ZS6 = well judged; ZS5 = good but less agile)
Cables: Aside from being detachable, nothing special on either. Get an upgrade cable.

The ZS5 mids are more laid back and lack the presence and projection the ZS6 has in my opinion. The ZS6 mids seem more front and center though I find the ZSR's midrange to have a better sense of density.

I should also mention that the ZS5(v1) have a lower sensitivity than the ZS6. The ZS5=4.8Ω @ 1kHz while the ZS6=16Ω @ 1kHz. The ZS5 need more power to reach the same volume as the ZS6. On my Fiio X3i, with both the ZS5 and the ZS6 simultaneously plugged into a splitter, I need to increase the volume for the ZS5 when trying to match volumes. For instance a comfortable volume for my ZS6 is 17/60 whereas the ZS5 must be set to 21/60 to reach the same volume.

In comparison to the BGVP DM5:

The DM5 is a bit of an anomaly. If it weren't for the slightly aggressive 2500hz lift and the odd imaging the DM5 would have probably outperformed the ZS6. The DM5 has the uncanny ability to separate and cast instruments further out to the left and right leaving a gaping and unnatural void between the center stage and the outer stage as if the vocalist is centerstage while all instruments are at the stage's extremities. Everything is clean and clear but the positioning is just odd. I've no idea how BGVP achieved this but from time to time I have to revisit the experience out of sheer curiosity.

When the ZS6 was released there were very few IEMs in the sub-$50 price bracket that could touch it's price-to-performance ratio. Nine months hence and the competition is a bit more stiff with the introduction of the TinAudio T2 ($50), KZ's own ED16 and a handful of other one-hit wonders.

In my estimation the few Chi-Fi manufacturers that have the resources to compete and the capability to scale with KZ are UiiSii, Tennmak and perhaps KZ-defectors TRN.

UiiSii is still finding their footing with hybrids (notice their Hi-905 has vanished from the marketplace) and Tennmak charges nearly double KZ's asking prices while they seemingly remain stuck in second gear. I haven't seen anything new or noteworthy from Tennmak or UiiSii lately and it'll be interesting to see how things develop with TRN (who make excellent cables) but what will be even more interesting is to see where KZ goes from here.

It appears that KZ's sound engineers do possess the skills to properly tune a design as complex as the ZS6. The ZS6 is one of my favorite IEMs and I wholeheartedly look forward to KZ's future endeavors.They typically offer "entertaining" sound signatures and on rare occasions they attempt to offer a neutral sound signature. Sometimes a "neutral" IEM can be dry and uninspiring but I'd still like to see KZ release a well balanced and beautifully machined CNC aluminum IEM for the diehard and persnickety audiophiles. Sure, they'll howl and wail about how it doesn't compare to their $2,500 trophy IEM or they'll make patronizing remarks like "for its price" but let's be clear. Companies like KZ Acoustics, Fiio and a handful of others are bringing great sounding gear to the huddled masses at one tenth of what comparable gear would have cost you just a few short years ago. When they get it wrong they push forward. When they get it right they push forward. Every passing month brings more promise and my anticipation, though measured, remains unabated. If their goal was to offer up an in-ear monitor that delivers an improved presentation of my music while simultaneously offering me a thoroughly entertaining IEM then I hereby dub their endeavor a success.

If you were to ask me to define the ZS6 in one single paragraph I would offer the following:

KZ Acoustics ZS6 is a beautifully machined aluminum IEM with an anodized satin-like paint finish. The dual dynamic drivers (6mm & 10mm) in conjunction with the dual balanced armatures (mid-to-high & ultra high) offer up a highly resolute and spacious sound signature. The ZS6 separates each instrument and then give said instruments their own sense of space and positioning on the stage in your mind's eye. The presentation is somewhat akin to attending a performance at an amphitheate (vivid and defined imaging in an open and airy acoustic setting). The ZS6's beefy bass is well-regulated, it's glistening treble delivers every detail with poise & transparency while the midrange is neatly perched so as not to be ignored (despite the mild "V" shape sound signature). In summary, the $40(+/-) entry fee is almost comical when you consider that a hybrid of this caliber would have cost several hundred dollars just a few short years ago. In my humble opinion, the ZS6 is an absolute treasure that should not be overlooked if you're in the market for an entertaining set of in-ear monitors because times........ well, times are a changin' friends.

I can not close out this review without telling you that it took an inordinate amount of time for me to review the ZS6. It wasn't just because I was trying to pin this or that down; it was mainly because I simply got lost in the music. The ZS6 is a vivid and entertaining in-ear with exceptional layering, imaging, separation and detail from top to bottom. It's the very reason this reviewer owns several pair of ZS6's.

Note:
Given KZ's penchant for "adjusting" their IEMs with ne'er a whisper I wouldn't be surprised if KZ have quietly upgraded the ZS6 (current production only) with their newer graphene dynamic drivers and their newly refined 30095 balanced armatures. If the ZS6 is still being produced then I owe it to myself and perhaps to our community to order just one more pair of my favorite in-ear monitors to find out if this is so.

Resistance is futile.



Hope this was helpful.

p.s. - I'm still waiting for KZ to revisit the sound signature of their HDS1.

.......someday.
__________

Now that you've got a solid description of what the ZS6 sounds like in its stock form let's take a look at what kind of magic Slater (our resident modifier) has worked into the ZS6 for the treble-sensitive enthusiasts. I would intimate that I, Slater and perhaps a few of the KZ veterans consider the price-to-performance ratio of the ZS6 to be so good that it should be enjoyed by as many people as possible. Those are my words and not Slater's or anyone else's but indeed Slater has furnished me with a sample of ZS6's that he personally modified for the treble-sensitive enthusiasts.

Our KZ thread here on Head-Fi is littered with feedback from users whom simply find the ZS6 to be too bright an IEM for them. Reliable FR graphs do illustrate the ZS6's aggressiveness particularly at the 10khz range. My own feedback regarding the ZS6's 10khz spike was recorded in my original review (above), though I have no particular aversion to it except on occasion. I find that less than 10% of the recordings in my personal music collection cross the borderline as "too aggressive" in the treble region. Pat Benatar's "Precious Time" album, Bruce Springsteen's "Born In The U.S.A." album and a few others can sometimes push the envelope but for me the ZS6 in it's stock form ticks nearly all of my "boxes".

For the treble-sensitive, though, the ZS6 upper frequencies may well be too aggressive. If you've been searching for a well-built and clean sounding IEM but you're a little gun-shy, due to reports that the ZS6 is a bit treble-happy, then this addendum is for you.

One of the KZ thread's most helpful contributors is a seemingly inexhaustible wealth of information about minor modifications that one can perform to shape the sound signature of a handful of IEM's more to one's own preferences.

"Slater" is one of our very own modification gurus on the Chi-Fi threads. Did you find the KZ ZS3 to be slightly boomy or was that Blitwolf sound signature slightly askew (not balanced enough)? Slater has offered up slight modifications to assist in cleaning up the sound signature on both of the aforementioned IEMs.

Recently, Slater posted some helpful information on how to successfully modify the ZS6 to temper the 10khz region for treble-sensitive users. On offer are two different modifications you can perform so long as you don't mind performing a little minor surgery on your ZS6. The first modification will be hereby dubbed the ZS6(sm1) and the second mod the ZS6(sm2).

Link to Slater's ZS6 mods (post #25083):
https://www.head-fi.org/threads/knowledge-zenith-kz-impressions-thread.698148/page-1673

I will be reviewing the ZS6(sm1) modification now and the ZS6(sm2) in the weeks to come so feel free to visit this review from time to time or follow the KZ Thread to keep abreast of any new and/or relevant information.

For consistency in volume I plugged both IEMs into a 3.5mm splitter and plugged said splitter into a Fiio X3(i). The Fiio X3(i) specs are as follows:

Output Power:
＞540 mW (16 Ω/THD+N＜1%)

Output Power 2:
＞270 mW (32 Ω/THD+N＜1%)

Output Power 3:
＞30 mW (300 Ω/THD+N＜1%)

Frequency Response:
20 Hz~20 kHz

SNR:
＞105 dB ( A-weighted)

Output Impedance:
＜0.3 Ω（32Ω

Crosstalk:
＞75 dB (1 kHz)

THD+N:
＜0.005% (1 kHz)

MAX Output Voltage:
＞8 Vp-p

MAX Output Current:
＞250 mA (For reference)


Both IEMs were tethered to the Fiio X3(i) with KZ's 4-cord silver plated transparent upgrade cables (with black rings). Thanks to Hakuzen's diligence we know that the impedance of this particular cable is
0.35/36/40 (left/right/ground).



The ZS6 (Slater Mod #1):

The ZS6(sm1) modification was achieved by modifying both the mid-bass dynamic driver and the high frequency balanced armature. It is a work in progress and as things develop and get dialed in we'll provide further details on how to properly modify your own ZS6.

In the case of this "sm1" the result of modifying the BA is a very subtle but effective drawdown of the 8khz to 11khz range by about 2db. To my ears it sounds somewhat akin to how KZ slightly tempered the treble on their ZSR model. It is not an identical presentation to the ZSR's treble as the ZSR seems to offer a more natural presence. The ZS6(sm1) treble, while still present, sounds as though it is subtly softened when comparing it directly with the stock ZS6's treble. The difference isn't huge but it is noticeable and it will render the ZS6 more tolerable for the treble-sensitive who'd like to enjoy a fatigue-free listening session without sacrificing much of the ZS6's micro-detail.

One thing to keep in mind is that the ZS6 in it's natural state is an IEM that, due to it's triple-vented faceplates, presents everything as if you are listening to a semi-open set of headphones. I intimated this about KZ's ZS5(v1) but it is even more so with the ZS6. The ZS5(v1), despite it's more recessed midrange, is still one of KZ's best tuned IEMs to my ears (when coupled to a low output impedance source). Comparing the ZS5(v1) with the stock ZS6 one gets the sense that the ZS5(v1) has slightly more body across the entire frequency range. Unlike the ZS6's triple-vented faceplate the ZS5(v1) faceplate has no vents "on" the actual facia of the IEM. No, the vents on the ZS5(v1) are found precisely where the faceplate attaches to the main body of the IEM. The gap between the faceplate and main body of the ZS5(v1) was measured with precision; it was designed to give the IEM a full-bodied yet airy presentation. Some early reviews of the ZS5(v1) mistook the thin gap between the faceplate and the main body as poor workmanship or poor quality control. That's an understandable oversight if one approaches KZ's finished products with an instilled bias against inexpensive gear or if one isn't particularly the observant type but I find the vents on the ZS5(v1) are an ingenious design because they give the IEM a sense of warmth and openness all at once that really works in the ZS5(v1)'s favor. Again, the design of the vents lend an overall sense of extra "body" to it's sound signature. My hypothesis is that the ZS5(v1)'s solid faceplate is not only a full point of reflection but the material (plastic) tends to absorb a wee bit of the energy whereas the ZS6's metal faceplate absorbs less energy while the vented faceplates, in a sense, open a window. You can tell that the ZS5(v1) and the ZS6 are siblings but the triple-vented faceplates give the ZS6 a distinctly different sense of the presentation.

How so?

1) The instruments are positioned in a more linear fashion from left to right on the ZS5(v1). On the ZS6 the vocalist is positioned more toward the front of the stage while guitars, strings and percussion are positioned for a more supportive role. Guitars, strings and percussion do not sound recessed, necessarily, but in comparison to the ZS5(v1) you can tell that each instrument is positioned to give the vocalist more presence on the stage.

2) The triple-vents on the facia give the ZS6 a more diffuse presentation allowing the mid-bass and sub-bass to breathe and decay in a more organic way. The ZS5(v1) vent design may lend more body to each note but it's mid-bass and sub-bass lose some of the definition found in the ZS6 presentation.

So, why the dissertation, Doc?

Primarily to set forth in detail the nuances that separate the two siblings before making my proclamation that the ZS6(sm1) bass sounds more akin to the bass of the ZS5(v1). The ZS6(sm1) bass is full and present but the modification to the mid-bass DD renders it slightly less defined than the stock ZS6 bass. Slater and I have discussed how the mid-bass is effected with this particular modification and he has determined that perhaps it is best to forego modifying the mid-bass DD. However, if you're a fan of the ZS5(v1)'s less analytical presentation then perhaps modifying the mid-bass dynamic driver may be just what it is you're craving. The drawdown of the treble in conjunction with the softer bass response get the ZS6(sm1) closer to a ZS5(v1) sound signature though the soundstage will differ.

Oddly enough this modification in its entirety also effects the upper midrange. Apparently, the ZS6's high frequency balanced armature spans from 4khz to 12khz where both sibilance in the upper midrange is found and piercing in the lower treble is found. Modifying the high frequency balanced armature gently rolls the definition. You still get decent definition but it's different.

Listening to Sade's "Kiss Of Life" on the ZS6(sm1) it's as if there is a thin foam cover on the microphone that softens her delivery when compared to the stock ZS6. Likewise, when reviewing Van Halen's "Girl Gone Bad" the upper midrange leans more towards comfort as opposed to raw delivery.



If you will recall I mentioned that less than ten percent of the recordings in my personal music collection approach the "borderline" or push the envelope in the upper midrange and/or lower treble regions of the spectrum. When reviewing Pat Benatar's ode to the broken heart in "Promises In The Dark" I did appreciate the modified ZS6's presentation a little more though the resonance present at the 1:53 to 2:03 mark was exposed on both the stock ZS6 and ZS6(sm1) equally. The first sample is "Promises" remastered but I actually prefer the standard version. To my ears the remaster may sound more dynamic but it sounds more artificial. The standard version which is untouched may sound slightly congested in comparison but Pat's voice sounds more natural.



The modification doesn't necessarily mask the music; everything is just as present...... just a tad softer...... which you will appreciate on remastered recordings such as this.

In closing I'd say that the only minor drawback of the ZS6(sm1) is a minor loss of composure the busier the track gets (due to the slightly slower bass decay). To my ears the stock ZS6 deftly handles the entire frequency spectrum from top to bottom but those accolades are lost if you're treble-sensitive; your ears simply can't abide the energy present in the treble region. If you're pining after a ZS6 that you can tweak or refashion to mitigate said treble energy then perhaps your prayers have been answered with Slater's ZS6(sm1).

By the way, don't place an inordinate amount of weight on my "loss of composure the busier the track gets" remarks; the effect is very minor.

Yours truly is looking forward to Slater's ZS6(sm2) because it will likely be somewhere between the stock ZS6 and the ZS6(sm1). I am a micro-detail addict so more micro-detail is better in my book. My red, black and green ZS6's are all in stock form. The ZS6(sm2) will be my fourth ZS6 and a welcome varietal of my favorite in-ear monitor. Stay tuned for my feedback on the ZS6(sm2) in the near future.

Hope this was helpful.

Specifications:

• Driver(s): Hybrid setup, 2xDynamic + 2xBalanced Armature
• Impedance: 15ohm
• Frequency Response: 7 Hz - 40 KHz
• Sensitivity: 105db

Price: U$D ~45. Available in 3 colors, Red, Green, Black.

Upgrade cable: ~$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. Note: the provided eartips didn’t offer a good seal/fit, so most of the listening impression is based on using SpinFit and similar single flange eartips options.


Design

The ZS6 follows the same shape and design as the previous ZS5 model, with the main difference of being made of metal (aluminum alloy) instead of plastic and adds some grills on the outer side of the shells. Needless to say that both ZS5 and ZS6 are following a Campfire Audio IEM design but with a more simple and plain finish. Like the ZS5 and many other KZ IEMs, the ZS6 also utilizes the 2-pin detachable cable feature; a less standard connectors of 0.75mm instead of the more common 0.78, but KZ already has an upgrade cable. The connection is quite good, much better than any standard MMCX option.

The ZS6 has a fixed over-ear wearing fit with a rather ‘polygonal’ look, that may a bit larger than the usual sub $50 IEMs and have potential fit issues for some people due the sharp ends. Isolation is around average and fit is a bit shallow because the short and straight nozzle.

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


Sound

Having listened to the ZS5 (v1) I was expecting a similar signature with some improvements overall on the newer ZS6. However, it was not the case. While technically the ZS6 is better in most of the sound areas over the ZS5, they noticeably differ in their presentation. If the ZS5 has a more standard v-shaped sound, with a warmer tonality and thicker mids, the ZS6 has much deeper V type of sound with a more pronounced bass and treble response, that while better in control it also makes the midrange more recessed and colder in tone.

The bass is quite powerful, rather linear through sub-bass to mid-bass, with a less lifted upper-bass. The depth is good with above average speed with the two dynamic setup. The quality and texture are quite good for the price, but it is missing on the fun factor that would be nice to have on these budget IEMs.

The midrange is the less favorable point on the ZS6 and biggest flaw. While it has the higher detail over any of the few KZ IEMs I tried, and also better than other similar priced options, it is missing in the whole presentation. Not only it sounds very distant but also has a very cold tonality and dry vocals. The ZS5 is richer and easier to listen (if you can tame the harsh treble down), and even the ES3 is much more enjoyable, sweeter in vocals more fun overall. Pairing the ZS6 with a warmer source is recommended.

The treble is elevated to match the amount of lows, and despite being so abundant it has the best control of the KZ other options, ES3 and ZS5. It has a same balance from low to upper treble as the bass, and it’s less sibilant too. Extension is decent and soundstage is around the average levels, if just trying to give a wider effect with the so v-shaped sound. For instance, paired with the Aune M1s, the ZS6 doesn’t have the so epic improvement in stage or imaging as the Fiio F3 or A&D D2 achieved.

These are the first "serious" earbuds I've purchased. I was going to replace my AKG K240 headphones which are getting old, but wanted to try IEMs as this seems to be the direction that "mid-fi" is moving towards. After seeing how inexpensive these are, I figured why not try them. (I can always buy more over the ear headphones!) But I had read about the dreaded "treble spike" and wondered if I would be able to hear this, or if it would bother me.

So I received them, and WOW that's harsh out of the box. Extremely pronounced upper mid-range. Cymbals, trumpet, and upper strings seem front and center, and bass was lacking across the board. Ouch. I knew this couldn't be how these were designed to sound. My crappy Skullcandy buds didn't have this issue. On the plus side, these have a WIDE soundstage. Instruments are seperated very well, which allows you to hear new things from old recordings.


Here's how I fixed the treble problem:
1. Low tech fix first. I placed two tiny pieces of of electrical tape over the exterior "vents". Since the tape is the same color as the IEMs (black) its not noticeable. So now I have more of a "sealed" IEM. Not sure how much this helped however.

2. I hooked them up to my AUNE T1 Mk2 headphone DAC/amp. This helped give me some lower end balance. I have the Tube DAC running from my Samsung S8 phone using the USB connection, otherwise the Tube doesn't come into play. Amplification isn't really needed with these, its just to get that warm Tube sound we like!

3. Purchased the upgraded "silver" cable. Fancy. Wasn't sure this would make a huge difference, but everyone was complaining about the crappy stock cable. And now I have a spare.

4. Changed the stock eartips for Comply Comfort Plus Premium Foam tips. I got the assorted size package for $22. That's Half the cost of the IEMs, and you know what - totally worth it. These change the sound quality of the ZS6's more than anything. Highs are still there, but they behave now. Bass is MUCH more present, but not overbearing, except perhaps with hard rock / metal. They sound divine with Classical, Jazz, and pop.

I am now enjoying these IEMs as they were meant to sound - warm, detailed, full soundstage, and good with every genre of music I throw at them. They are more comfortable now, and that's very important for someone replacing a pair of on-ear headphones with IEMs. Do they sound like a $350 IEM? Dunno, but they sound better than the $68.00 total I invested. (Am not counting the cost of the Aune T1, had that for a few years.)

Cheers!

In audiophile world, the price over performance ratio has always been one of a buying factor. The recent price hike in audio world ignites the concern of most audio enthusiast and audiophile globally. Headphones like HiFiman Shangri-la, Susvara, and Sennheiser HE1 are the big names in the end spectrum and it does not stop there. Custom or high-end universal IEM could even go up to $3000 to $4000 range. There will be more brands that aim for a state of art headphones in justifying their price tag. Most people in audiophile society are a mid-class level that only had the opportunity to listen to high-end setup at a convention, audio shops and meet. Well, the general rule in this hobby is a more expensive gear tends to provide a better quality; however, there are numbers of brands that punch above their price and KZ brand IEM is one of them. KZs are well-known for They have high praised IEMs lineup like KZ ZST, ED3, HDS1, ZS3, ZS5 and many others. Recently, the company release yet another great flagship IEM called KZ ZS6, a better version of the already amazing KZ ZS5.



Order and Package

It took about a month from the order date and the day it arrived in my mailbox. Unboxing experience is regular, nothing fancy; you will get three sizes of S, M and L ear tips, 2-pin cable with in-line mic (if you choose mic option upon ordering), documentation and the IEM itself. The cable has a decent quality, not the best but not the worst, and the microphone is quite good; better than my KZ HDS1 at least. I ended up getting a silver cable for aesthetic and build quality purpose. Not expecting any change in sound quality but it might bring something to the table.

Build and Comfort

The design is pretty similar to ZS5, albeit ZS6 a slight bigger. Despite a little larger than ZS5, it feels more comfortable and has a better fit than ZS5; this might differ in person, but it has a good fit with my ears. However, after an extensive number of hours on it, I realized that the tip could come off easily. I am not talking about the Starline ear tips, I am using the JVC Spiral Dot, but it happens occasionally. The housing feels solid with a gorgeous color option: black, red and green. Personally, I love the color lineup compares to ZS5 and I go for red because it is one of my favorite colors. Build quality is amazing for its price; KZ uses aluminum alloy houses instead of plastic which is a great addition to this lineup. I am using them with the wire over my earlobe and I am pretty sure that you can’t use them under ears.




Specification

Shell: Aluminum alloy

Driver unit: 2 dynamic, 2 balanced armature

Impedance: 15 ohms

Frequency response: 7 Hz–40 kHz

Sensitivity: 105 dB +/- 3 dB

Noise cancellation: active

Cable: 47.3 in (120 cm) +/- 2 in (5 cm), removable 2-pin

Connectors: 3.5 mm info from KZaudio Aliexpress page

Included

IEM: KZ ZS6

Cable: original 2-pin removal cable

Tips: S, M and L sizes



Gear used:

IEMs: KZ ZS6, KZ ZS5v2, KZ ZSR, Westone 30, AAW Nebula One and Fiio F1

DAC: Holo Spring DAC Level 3 Kitsune Edition, iDSD Nano BL

Amp: ECP DSHA-0, Emotiva BasX A-100, Marantz PM8005, Aune B1S, Aune B1

DAP: Pioneer XDP-100r, Colorfly C3


Note: Review is made after more than 100 hours of burn in but constantly tested in 100 hours period. Mainly tested on Tidal Master > Singxer SU-1 > Holo Spring Level 3 > ECP DSHA-0 Balanced > KZ ZS6.


Review Song

Daft Punk – Lose Yourself to Dance

This song is quite complex and there are a lot of things going on in the song. Everything just mixes up to but in a harmonic way. The ZS6 breathe perfectly throughout the song and I can hear every drum, guitar, the vocal that came out from multiple directions with ease. I enjoy this song with full size as it gives more impact and faster transient response. The ZS6 lacks in speed with this song but the retention time filled with a flow of rhythm. I utterly enjoy this song with ZS6.

Melody Gardot – Our Love is Easy

Female vocal is the emphasis of the song accompanied by jazz and orchestral mixed background. Layering and separation is the strongest trait on ZS6 and as you would expect, it does not disappoint and in fact, it’s doing quite well with female vocal in general. The mids is engaging and the spacious sound let you focus on the singer performance. Although the midbass is somehow lacking, the overall bass is accurate and well controlled.

L’Aupaire – Dancing in the Moonlight

The song starts with guitar strumming followed with drum kicks that provide a relaxing but impactful opening. Every instrument that comes into play were there but somewhat hazy. What I meant by that was that it doesn’t sound too natural. However, I love the vocal because it gives a good presence of the singer without excluding the background instrument.



Sound
0 – 50 hours burn in

It felt a little muffled at first. I have the same exact experience with KZ ZS5 and after 3 – 4 hours, the sound started to come to life. It has natural and lively mids but bass is subpar with overwhelming treble extension; the treble might be a little too much for some. The vocal and upper mids sound harsh coming from Westone 30. The guitar player from Hotel California sounds over emphasis to a point it doesn’t feel natural. The soundstage has a good width and depth for IEM and it is above average. I personally feel like the bass has too much quantity but not punchy and less impact. It is great for most songs but sometimes the midbass is overstated that cause the sub-bass to roll off or not pronounced especially with a song like On My Level by Wiz Khalifa. The mids is the strength on the ZS6 and it never struggles with any female or male vocal song. Every word is pronounced accurately but there is a spike around 4 to 6kHz that exaggerate any word that ends with S. For long listening, if you don’t have any warm amp, it could be fatiguing.

50 – 100 hours burn in

Not much or no improvement ever since. The sound still retains, and the nasty treble is still there. I am not too sensitive to treble as how I used too but at times, the ZS6 treble does bother me. Although I am not a fan of EQ, I find that it might help if I tone down the 4 kHz for 2 or 3 db. I decided to add Schiit Loki to the chain and it does bring more pleasant listening experience. Not by a whole lot but it is noticeable. I also bump up the low end to few dbs and I love how it adds more quantity and texture to the bass.

After 100 hours

Honestly, I can’t remember when does this starts but I felt like the spike toned down a bit and the bass are more apparent; more body and enjoyable. Then, I use the ZS6 with my portable setup again to see if there’s better synergy. The first thing I noticed was the vocals; smoother but retains clarity. The bass is more articulate but still on the soft side and less impact. The ZS6 has a good tonal balance albeit the spike in the upper midrange. It is more on the neutral side and works perfectly for acoustic and classical song. For modern songs like EDM and pop, while they sound great on ZS6, I would personally go for other IEM in this regard.



Pairing

I have it paired with a few pairings from full-size desktop amp to portable amp. I am also using a third-party silver cable and change the ear tips for better results. I found that the best pairing is as shown below:

Desktop
Tidal Master/Foobar > Holo Spring Level 3 > ECP DSHA-0 > KZ ZS6

Portable
DSD > Pioneer XDP 100r > Idsd Nano BL > Aune B1s > KZ ZS6

Both setups tones down the nasty spike but at the same time maximizing the detail retrieval. It brings more holographic sound to the setup. I found that it sounds more musical with my portable setup but more detail and neutral with my desktop setup. It also has more bass response with my desktop setup. Although, I enjoy the ZS6 with both setups and mostly use the ZS6 with my portable setup because I have more capable full-sized headphones to be used with my desktop setup.


IEM comparison


Vs KZ ZSR ($28)

More neutral, better clarity and brighter. ZS6 is more neutral and good for audio purist that wants to avoid any coloration to their IEM. ZSR has more relaxed sounds with a larger soundstage. The tonal balance in ZSR is more to my liking as I can enjoy more songs with ZSR. Although, clarity is the tradeoff as I put ZSR in my ear. ZS6 has more detail retrieval and but also can be a little congested at the same time. ZSR has more space to breathe and the bass response does surprise me because it has more body and well-controlled compares to ZS6 that I find to be lacking in this regard. ZS6 is more on the brighter side while ZSR sparkle at the right amount but never roll off by any means. In my ears, ZSR has a better fit while ZS6 easily comes off. Overall, if I had to choose only one between them, I would go for ZSR because it suits more genre and good for a long listening session.



Vs Westone 30 ($235)

Better clarity and brighter. While I love ZS6, I don’t think that it can top off my most favorite IEM all times by far. ZS6 is a clarity monster but that might also result from the increase in the upper midrange. Westone 30 has better tonal balance and more articulate highs with well-extended bass. However, the mids on W30 sound recessed when both were compared together. Soundstage goes for ZS6 but imaging has a different presence on them; ZS6 tends to have more separation and it seems like you were in a front row of a show. However, in W30, it seems like you were on the stage with the performers. W30 has a faster transient response and more speed; that’s what I like with the IEM. ZS6 can be a little slow in dynamic response and less forgiving. It stays true with any track you throw in. Overall, they are different and in fact, very different. It is a matter of preferences and mine goes to W30 but of course at almost 6 or 7 times ZS6’s price.


Conclusion
There are times that I prefer ZS6 especially when I listen to acoustic or classical songs. But, I would go for different IEMs with another genre. Earlier, I mentioned that ZSR is the more capable IEM because it goes well with most popular genre. But for its price, ZS6 is a great IEM that competes in a considerably saturated market but managed to make its way up and well received by consumers. Note that, a setup synergy will be important to bring out the best from KZ ZS6.

This week I finally received the KZ ZS6 Quad Drivers to which I was really looking forward to. I noticed a lot of people were praising this pair of earphones, so I had to get them! At the moment I put these earphones in and start listening I immediately got blown away by its sound! Dam, these sound awesome. Its the combination of the performance on all frequencies together with the wide soundstage makes these earphones outstanding!

Sound
The KZ ZS6 are driven by 2 Dynamic and 2 Balanced Armatures on each side. Its like they put mini loudspeaker into this earphone, for all frequencies an independent driver. The Dynamic Armatures are designed to produce the low and middle range frequencies, whereas the 2 Balanced Armatures are producing the high’s. The lower frequencies produced by the KZ ZS 6 offers great depth and is punchy, without leaking and bleeding into the other frequencies. It makes them extreme accurate! The middle tones are very crispy and clear, which makes vocals sound awesome. You can really hear the benefits of the independent drivers is the different frequencies, each frequency sound really detailed, without the cost of other frequencies. Finally the high’s are just so crispy, without being harsh on your ears. Based on the performance of the frequencies it beats out earphones like Urbanfun Hifi, Xiaomi Hybrid HD and Einsear T2 (which were my favorite 3). Now, another part that separates KZ ZS6 from the competition is the amazing soundstage it provides! The sound is so open and wide, that it provides you the same feeling as listening to my floor standing loudspeakers! The different sounds of instruments are really placed into the air, which provides this open and wide feeling. This combination of the excellent frequencies and soundstage, makes this pair of earphones outstanding!

Design & Build Quality
The KZ ZS6 offer real premium design by the high quality materials used on manufacturing these. The earbuds built by Aluminum Alloy materials, which makes them feel really solid. Stainless screws are applied to keep the earbuds together. The cable of the KZ ZS6 is detachable, which makes it easy to place the cable when it get broken. Besides that its replaceable, you can also buy a bluetooth module that you can attach the the KZ ZS6. The headphone jacket is L-shaped, which is a win for me. Overall, premium build quality.

Comfort
The KZ ZS6 have an backward design. I used not to be really a fan of these kind of designs, due to my experience with the KZ Ate, that were really uncomfortable for me. However, I got really surprised that these were so comfortable for me! The good about this design is that they really fit secure and makes them sit on the place, when being active like working out or go out for a walk or run. The downside for me is that it takes some more effort to get them in and out. When I’m working I prefer having earphones that I can easily pull out, when I want to start a conversation with someone. The eartips included to the earphone are in small/medium/large, for which I am using large ones which are very comfortable (a lot of times I replace the eartips of the earphones, but not necessary for the KZ ZS6). When listening longer listening sessions to these they keep being comfortable, however sometimes I need to press a bit on the side’s of the earphones to get them back in the place where I wanted.

Conclusion
As the title of this review already mentions, I really got blown away by these earphones! KZ did an awesome job and set a new standard of high quality earphones in the market. These are really a step up of the current offerings around this budget on the market. It beats earphones like the Urbanfun Hifi, Xiaomi Hybrid HD and Einsear T2 if look at the whole package. It really feels these are playing on a whole different level! The excellent sound quality produced on all frequencies combined with it’s soundstage creates an amazing listening experience. The premium build quality makes them look and feel awesome. Finally, with being comfortable I have not been able to find any cons on these earphones! The backward’s design may be a con if you prefer earphones that you can easily pull in and out. These are definitely one of my new favorite earphones!

GearBest link: https://www.banggood.com/KZ-ZS6-HiF...adphone-p-1197912.html?p=8S0707520102201404E4

This review was originally posted on EarphoneKing.com

Please forgive me for the hyperbole. I couldn't help it. :-D

You can currently pick up the ZS6 for about $30 from a few places such as AliExpress(use the app!) and GearBest if you don't mind waiting a bit for it to arrive from China, or you can get it on Amazon for like $46.

Specs

• KZ
• Shell: Aluminum alloy
• Driver unit: 2 dynamic, 2 balanced armature
• Impedance: 15 ohms
• Frequency response: 7 Hz–40 kHz
• Sensitivity: 105 dB +/- 3 dB
• Active noise cancellation
• Cable: 47.3 in (120 cm) +/- 2 in (5 cm), removable 2-pin
• Connectors: 3.5 mm

Intro
Knowledge Zenith(henceforth referred to as 'KZ') first popped on my radar about two-and-a-half years ago. People were raving about their dirt-cheap budget offerings such as the ATE and ED9.

I popped for the aforementioned ATE, and when it arrived, I was mildly impressed. It was very good "for the price." But it wasn't Monoprice 8320 good-for-the-price if you know what I mean. I shelved them or gave them away, or fed them to a monkey or used them to help me diffuse a bomb MacGyver-style...I'm not really sure, I've drank a lot since then.

Anyway, fast forward a couple years and I'm looking to dip my toes back into the earphone game, and the KZ fervor seems to have escalated to an even greater pitch. Their hybrids catch my attention. Now, back in 2015 most hybrids were far from being affordable and even less were considered "budget." Remember the TTPOD T2? People were losing their minds at the thought of a triple-driver hybrid for <$100. Buuuuut it was more disappointing than the first time I had sex.

Techmolololgy has come along nicely however, as the KZ ZST was pretty good! Especially for the price. I wish I hadn't given it away to a girl who eventually played me. Anyway, cue the ZS6, KZ's current four-driver hybrid flagship. An evolution of the ZS5, it bears a striking resemblance to one of the sexiest earphones I've ever layer eyes on. So I had to have it. How does it sound? Read on. :-D

Unboxing/Presentation



KZ keeps things pretty bare-bones. I suppose that's one way of keeping costs down. It's just a simple white box, and when you remove the outer sleeve you're greeted by the earphones nestled behind a clear layer of plastic.

Accessories

Again, not much to talk about. I don't even know why I'm bothering with these first two sections. I suppose it will make my review seem more "professional." instead I will just tell a joke. Did you hear about the constipated mathematician? He worked his problem out with a pencil. OK, moving on.

Build, comfort, and isolation

I'm pretty confident that the ZS6 will stand the test of time. The shells are made of metal and the two halves are held together by three screws. At least I assume they are. If they're just there for aesthetics that would be a bit of a disappointment. The nozzle is also metal with a thin metal filter in the tip.


The cable the ZS6 comes with is a rubbery, springy thing that works just fine, but can be a bit of a nuisance in how it behaves. You can use a twist tie as a cable cinch and that will help it from bowing out on you while wearing it. I like the ZS6 enough that I decided to pick up something a little more subtle and aesthetically pleasing.

Comfort for me was, at first, terrible. The ZS6 isn't a small earphone and it has more than a few sharp angles. I couldn't use it for more than like 20 minutes at a time without my ears protesting. But, I got used to them. And now they're comfortable for much longer periods without any hotspots. They're pretty light too considering they're metal, so that helps. If you have small ears though, you might want to get them from a place that has a solid returns policy. Otherwise you should be fine. Oh by the way, for me these aren't sleepable. They jut out a bit too much and if you lay on your side the pressure can cause the sharp edges to go all stabby on your ears.

The ZS6 is a vented earphone, with one vent on the belly and the other three on the face behind a classy metal mesh. I'd say is isolation is pretty average. But I imagine for most people they'll suffice for the gym and jogging around the neighborhood.

Sound

Ah, the meat and potatoes. Did you guys know that really isn't considered a balanced diet? But I digress. Anyway, the ZS6 overall has a bright, energetic signature with clear mids, ample bass, and a big soundstage.

A lot of people have complained about the brightness, saying it's too much. It isn't for me. Maybe on the occasional track but not often enough to be an issue. In tracks like this, the treble provides plenty of sparkle without becoming overbearing(for me), nor does it steal attention away from the bass and mids. In Growing of the World by Jessica Curry the treble definitely comes on strong, overshadowing the vocals a bit but it does help impart a sense of air. Just maybe don't listen to too many songs like that in a row.

Regarding the mids...people refer to this as a v-shaped earphone, and I can see why. But the mids don't sound distant, or obviously recessed. The ZS6 is more balanced than say, the DM5. In songs like this the vocals come through loud and clear. Maybe a smidgen recessed.

Female vocals tend to have a bit more gravitas to them, but male vocalists sound pretty darn good through these boogers too. As far as vocal timbre is concerned they lose out to some more expensive models but the gap isn't as big as you might think.

These aren't bass monsters by any stretch, unless you compare them to something relatively bass-light like the Dunu Titan 3. The bass is rumbly and tactile with nice texture and good attack and decay. The low low bass in Losing the Light Explosions in the Sky will rattle your eardrums, but never gets in the way unless the track asks for it.

The soundstage is fantastic for the price point and up. It's one of the widest I've heard in a long time, beating out more expensive models in sheer width. Depth and height isn't as impressive but it's still pretty good as is instrument separation. I really can't speak highly enough of the soundstage of the ZS6. It's capable of throwing cues further outside your head space than something like the Shockwave 3, which is considerably more expensive.

Comparisons
Hope you guys don't mind some copy pasta...
DM5 vs. KZ ZS6


Two sub-$100 quad-driver IEMs!? Oh, what a time to be alive!
Both are two BA/two DD hybrids!
The DM5 and the ZS6 actually share a similar signature, although the latter is more balanced due to the mids being more forward in the mix. The ZS6 has a wider soundstage and as such sounds more spacious(despite the more forward mids). The ZS6 also has an elevated sub-bass response but less so than the DM5. Both have great, almost tactile rumble in songs like this.

ZS6 vs. Sony MDR EX800ST/7550 w/EX1000 cable


I know this comparison doesn't make a whole lot of sense, but I thought it could be interesting to see how the ZS6, with its very impressive soundstage, matches up against one of the soundstage legends.

Let me be clear - The Sony is better in pretty much every regard. Timbre, instrument separation, it's black background, etc. And overall, it has a better stage. It's deeper, taller, and almost as wide as the ZS6. Yeah that's right, almost. That should give you an idea of how impressive the ZS6 is.

Of course, the ZS6 will provide better isolation and a more stylish profile. Also, it's roughly ten times less expensive. So there's that.

Summary

If you like a bright signature I can't recommend the ZS6 enough. It is fantastic for the price, and then some. Comfort might be an issue for a few people, as might be the treble. You can always use foam tips to mitigate the former and as long as your ears aren't small I think you'll be OK with the latter. Not to mention they look dead-sexy. For me they are an easy recommendation and a 5/5 despite the cons.

Hoorah!

Unfiltered First Impression:

The KZ ZS6, $40 Quad Driver Balanced Armature IEM's, impressive in build and encapsulated in a simple but minimalist presentation upon unboxing. The second thing I noticed upon insertion is micro-detailing, I’d say this is the best IEM I’ve heard that creates a coherent presentation while putting details as the top priority, and thanks to the quad drivers, instruments separate themselves to boost an already revealing sound signature. True, I’ve never heard quad driver IEM’s before, as they often come in custom shells, and I’ve never really felt the motivation to go for ear impressions; but for $50, I’m genuinely impressed this has surpassed other earphones like my ER4S (single BA) and iSine 20’s (planar magnetic) to reveal this much in music.

Music and Sound Impressions

I would recommend these IEM’s for contemporary music, jazz, soundtracks, refined pop music (Bee Gees for example), classic rock and whatever music you believe has a refined treble mastering. Because believe me, these are not even close to forgiving. If you’re curious as to why I left out classical music, it’s because there’s quite a dip in the lower treble area that’s hard to notice until violins start playing along. In which violins sound congested and listening immersion is broken off at this point. That’s not to say these IEM’s are congested though, these sound very open. The soundstage is very wide with good imaging, vocals extend, bass can extend deep and has a bit of punch, and the treble of course is quite prominent but only sibilant with aggressive tracks. Another thing I’d like to add about the sound is that the ZS6 are flexible with equalization in which they respond well to mid and treble adjustments. Although with the bass... in hopes of adding a little more weight in the sub-bass department strictly to compensate for outside noise, I ended up with distortion, essentially mimicking fart cannons. During quiet listening sessions, I’ve had absolutely no problems with bass quantity. Or quality for that matter.

Efficiency and Amplification

On the flip side, the KZ ZS6 are very efficient and powering them through an amplifier pretty much destroys music with more treble. Ironically I plugged these into my Oneplus 5 after and I would turn my amp's volume knob left and right wondering why the volume wasn't changing. Suffice to say, these sound absolutely amazing powered by a phone and I’m confident enough to say the KZ’s can put my amplifier out of commission with no hesitation. I believe I should thank the 15 ohm efficiency for achieving this feat, and I’m surprised the ZS6 has an extremely low noise floor paired with this efficiency.

Design and Comfort

Design is above average for the cost, I’m grateful that KZ didn’t miss the minor details. Such as an L-shape jack for portability, a sleek design (that looks familiar elsewhere), and memory wire for over-ear. However I seem to have a tad of an issue with the memory wire, it sticks out from the housing quite a bit and isn’t flexible so it’s hard to get a wrap around my ear properly. However if you’re someone with relatively large ears and can wear ear hooks similar to the Monoprice M300 or iSine 10/20, these ear hooks will do just fine.

Thanks for Reading~

The manual says the KZ will benefit from burn-in, and I’m on the fence when stating my opinion to the public when it comes to this. But after my trip with burn-in last year with the Beyerdynamic Custom One Pros, I think I’ll give KZ the benefit of the doubt this time. A 4/5 with my ears at this cost, well done KZ.

Outstanding value for these 4 driver hybrid IEM's. I bought these to try out and I was completely taken off guard. The sound on them was really good almost as good as my UE900s.

These don't have the UE900s neutral sound signature but they do have a sound stage that is relatively wide and the ZS6 is able to pull out details nearly as good as the UE900s.

$40 and they're able to compete with the UE900s? Well not quite. They do have a bit of an issue with a treble spike somewhere in the 7k region, but a quick EQ will solve that. Oh and the mids are a bit recessed and could be better.

Overall a great value.

I must admit before I heard them I was totally open minded and wasn't expecting much. Ok the ZS5 has received pretty favourable reviews and the 6 was going to expand on that. By all accounts it has been a success. I went for the green finish as I thought it looked great and from a distance Campfire Audio esque in looks. Ok just to get the one negative out of the way. There is a nasty harsh treble Spike, it's there but look it cost €45. In some cases at low volume it can be really enjoyable, it's a breath of fresh air with it's energetic feel. However at high to mid volume it can become unbearable and also the fit isn't great they move about a bit in your ear. If you're looking for best in class sound insulation again you're going to be disappointed here. But above all I didn't think you could get this kind of quality for this price it's amazing for the money. Huge soundstage and infinite detail even on the most demanding of tracks are all attributes that the KZ ZS6 has in abundance. Just buy a pair. Christmas is coming and it's an amazing stocking filler. Sounds at least treble the price it is.

These are a great update to the ZS5, but aren't necessarily worth it if you already own the 5. The sound is nearly identical, including the harsh treble and boost in the presence range. If you broke your plastic ZS5, get these- they're metal and won't break the same way. They don't address any shortcomings except build quality.

Where the 5 was an amazing value, the 6 is that much more of a deal for being metal. That said, expect the same issues with SQ. Non-existent to poor imaging and brutally harsh treble zing, but for $35 shipped, zero complaints.

*UPDATE*

I ordered the silver cable ($19) and a set of Ostry tips ($12).

I can't tell if the cable makes a difference, but Ostry red tips tamed the treble. Keep in mind that these are no longer $35 headphones- they're closer to $70 after shipping. Was it worth it? Emphatic YES. You'd be fine just ordering Ostry reds ($8) instead of the variety pack. The new cable is way less microphonic, but is also missing the microphone and control button. I'm happy with it, but it's not necessary for SQ unless you lost the factory cable QC lottery.

If you want to give these headphones a shot, order the Ostry tips at the same time.

These are still a 4.0 out of the box and it's not really fair to hand them a 5 for non-factory upgrades which double the price. SQ is definitely a 5 now, but they should come sounding like this straight from the factory. Even with the upgrades they're still a tremendous value. Highly recommend!

Overall these are much better than their predecessor the kz zs5's. The treble control is way better and the bass is improved as well! I don't think that there are many earphones out there that sound this good for the price! I didn't expect them to be that good, given the fact that I was very disappointed with the kz zs5. They sound better than most of my earphones that are below £100

I got these earphones as a review unit from Gearbest.com, i specifically requested to review these in light of the very intriguing specifications of the ZS6.


Specific product page: https://www.gearbest.com/earbud-headphones/pp_770863.html?lkid=10690141

Notice that right now there's a code that cuts the price to 29.32$ !
Just enter code " 4ALL5 " at the "cart" page on GB.



Now on to the review:


Package\accessories:

The ZS6 arrive in a carboard box surrounded by white paper wrapping. Inside you can find the earphones, a 2-pin detachable cable and S/M/L sized silicone ear tips.




Sound:

In my ZS5 review I had a hard time rating the sound, mainly because they sounded different with each song.

This time, I feel as if I can grade the ZS6's more easily as they are more consistent in terms of sound and performance.


The ZS6 on the left, next to the ZS5 on the right.


I would describe the sound signature as v-shaped.
The bass is a bit emphasized, yet far away from being dominant or overbearing and the treble is sizzling and more emphasized than the Bass and the Mids.

This sound signature makes for a very enjoyable experience as it's quite energetic and gives the listener the impression of a detailed and clear sound.

It's hard for me to ask for anything more really, when i listen to the ZS6 I don't feel as if I'm missing anything in the sound spectrum.

I'm usually very sensitive to sibilance and High-mids yet i didn't have a real problem with the ZS6 in that regard, my only complaint this time is that the Treble is a bit dominant in certain songs (Ace Of Base – The Sign for example).

The Treble is not sibilant, it's just a bit dominant compared to the bass and mids sometimes, but I have similar experience with my Denon AH-D2000 and other famous full-sized headphones.





Soundstage wise, I would say the experience resembles sitting with the artist in a recording studio. It doesn't sound congested or dark, it sounds intimate yet more organic than previous KZ models I've tried.


Bass: Grade: 5/5
Just the right amount, there's enough of it to make genres such as EDM and rap enjoyable, yet it only plays a supporting role when listening to more acoustic oriented music.


Midrange (500hz-2.5K): Grade: 5/5
The ZS6 definitely has impressive abilities on this end of the spectrum! From vocals to pianos to electric guitars...i have yet to experience this kind of quality in Chinese earphones.
The ZS5 comes close, but the ZS6 are more consistent from song to song.


Upper Midrange (~2.5khz-5.2khz): Grade: 5/5
What can i say? if don't find this area harsh or cheap sounding i'm giving it a perfect mark.
Good job by KZ for paying attention to the tuning of this area.


Treble: Grade: 4.8/5 (a matter of personal taste)
Most of the time it's great, in some songs there's too much of it. Nothing that a bit of EQ adjustment can't fix though.



Isolation and sound Leak:

As these seem to use some kind of semi-open design, they don't isolate quite as well as the ZS3, but not many budget earphones can compete with the ZS3 in that regard.

When music is playing the ZS6 can handle street noise just fine, they're just not meant to be completely close and isolated.

This also means that those who will sit right next to you on the bus would also get a taste of that delicious treble.


Verdict:

If someone told me I had to pick between keeping the ZS6 or all my other wired earphones combined (inventory in profile), then I would pick the ZS6.

They are a level above every earphone that I own.

What I like the most about them is their versatility and ability to sound good across all genres.

If the ZS6 are within your budget, then I would definitely recommend buying them instead of buying one of the cheaper budget earphones and then upgrading non-stop.

If feel that the ZS6 are the real upgrade i've been looking for ever since i got my first "bang for the buck" budget earphones.
The ZS6 are not just another set of "budget earphones" – KZ is competing against the big brands now.

KZ ZS6 review



First off, a heart-felt thank you to George and Gearbest for providing these headphones. New gear is always fun and the opportunity to try out gear as it comes to market is indeed a privilege.

A short note about me: I am a music enthusiast, and audio hobbyist. I make no claim to have the level of experience of some here. I tend to be quite pragmatic and value oriented. This means KZ products are quite familiar and fit well in my usage patterns. I am a lover of blues, jazz, and rock music and listen to a very broad range as I am always interested in what is new. I have purchased the Zs5, Zst, ED12, Ed9, and the ATE v2 (most of them from Gearbest) along the way but was given the Zs6 in exchange for this review.



Review:

The Zs6 arrived in a typical manila padded envelope. The box is similar to the familiar KZ box with the black cardboard back and the transparent front but is a bit more upscale. It is now white with a slide off cover with graphics on the front and specs on the reverse as shown below. The transparent front displays the earpieces and a large KZ logo in a display tray with the cables etc. hidden behind. The display shows a very good-looking earpiece with three screws holding the side plate on instead of the normal glue. At first glance, the build quality seems a step above the expectation for KZ.




Accessories:

In a word, typical. Again, those of us that have bought KZ before will know the typical what comes in the box. It consists of a cable, 3 sets of tips in small, medium, and large, and a brief manual. While this has come to be expected, I had hoped with the step up in the IEM itself for KZ, the cables etc. would receive the same upgrades. This does not appear to be the case as no additional tips, cables, or accessories are provided in the box.




Build Quality:

Build quality is definitely a step above what I have seen from KZ before. The aluminum is anodized evenly with no visible gaps or discoloration. The screws are all snugged tightly but easily broken loose to dismantle them should you so desire. If there is a complaint on the build of the earpiece itself it would be that the screen on the barrel is pressed in rather than fitted. I am sure the glue will hold fine, but a machined part with the screen held in place would have been preferable (and probably a lot more costly).




The cable on the other hand, is the same cable we have seen KZ use on all their removable IEMs to date. The wires themselves seem to be coated in an almost plasti-dip rubber coating which does help keep noise down but also is borderline sticky. The two pin connectors are well marked L and R although the front and rear pin position (in phase/vs backward) is less immediately identifiable. They also retain the overly stiff memory wire from previous versions which I usually go about removing with a needle nose plier and a razor blade. The Jack is a 90-degree L shape and is a welcome sight as it is my preference vs the straight model.





Microphone:

The microphone worked well for making calls and didn’t pick up a lot of extraneous noise. It did suffer from the same issues with wind and rubbing on clothing as you walk that pretty much all in-line microphones do. My personal preference is for cables without the microphone but I’m sure others will find it useful.



Sound:

As mentioned at the top, I am a lover of blues, blues/rock, classic rock, and anything with good guitar work in it. For that reason, I use the following as my test tracks. (artist, album, track, thoughts)

Stevie Ray Vaughan – Texas Flood – Lenny (Guitar to die for but the thing I look for is the percussion.)

Lindsey Buckingham – Fleetwood Mac, Best of - Go Insane, Live (Probably the most complicated simple song you’ll ever hear, all about nuance and subtleties with this track).

Johny Lang – Lie to me – Lie to Me (Looking for tight bass, bleed over into the mids, and controlled sub-bass)

Tedeschi Trucks – Let me get by – I want more (Female Vocals, backing brass band)

The Blasters - Testament – Blue Shadows (Saxophone and piano with male vocals)

Vintage Trouble – The Bomb shelter sessions - Blues hand me down (Looking at attack speed and decay especially in bass and sub-bass. This track gets muddy quick if the equipment can’t handle it.)


Treble: I put treble first in this review which is not my usual sequence but it is the first thing you notice on the Zs6. The treble is over-stated pretty substantially in the 8-10kHz range. I find that I need to adjust the graphic EQ on foobar down 6db at 8kHz and 8db at 10kHz to help tone down what can only be described as a hot treble. Once tuned a bit, that extra treble does have good extension and plenty of sparkle. Cymbals are lifelike and well detailed and the flute on Jethro Tull’s pieces was very well rendered. Without the EQ adjustments, the cymbals tend to take on a metallic sound and the flute loses the softness Ian Anderson was known for. Those who love a treble forward IEM will truly revel in the Zs6. Those who like good treble extension and lots of detail will enjoy the Zs6 too, it just may take a few attempts to get the EQ setting where you want it.

Mids: Once you get past the treble, you are rewarded with what I think is easily the best sounding IEM KZ has made to date. Mids are well rendered. Instrument separation is good, and presentation is more open than most. Soundstage isn’t huge, but isn’t claustrophobic either. Vocals are particularly susceptible to poor recordings and it would be easy to blame a lot on the IEM if you are not careful in selecting well mastered and well recorded tracks. The Zs6 is not particularly forgiving of poor source material.


Bass: This is where I think the Zs6 really shines. It is not the typical consumer oriented, bass boosted, beats-esque pattern we hear so frequently. Bass is tight and present in proportion to the rest of the sound signature. Again, it would be easy to say these didn’t have good extension or slam if you chose the wrong source material as they don’t seem to add to what the recording presents. I had to listen to some older EDM to really test out the bass as a lot of the predominantly guitar tracks I listen too didn’t provide enough bass-line to really study what the Zs6 was doing. The walking bass line at the start of Duran Duran, A View to a kill became one of my test tracks for this reason. Sub bass is present in good quantity and is controlled better than expected as it didn’t tend to get sloppier as volumes increased as is a common problem.



Thoughts:

My first thoughts were that the piercing treble was going to keep the Zs6 from being something I could listen to for very long, but once EQ’d a bit, I must admit the Zs6 has enough detail and balance that I found myself coming back to them. They are really very good, except for that one treble spike. So, I began to look for ways to correct it.

First came the cable upgrade. I went to one of the silver replacement cables available on amazon as I had read from another head-fi member that he suspected the cable might be at fault for some of the issues with the sound. I can say that I don’t believe the cable made a bit of difference in the sound but I do like the microphonics of the new cable better so it will stay.




Next came tip rolling. I tried JVC Spiral dots, Comply Foams of two types, Rebound foams, spin-fits, and a mix of other KZ tips I had from previous purchases. All made some difference and when coupled with the EQ adjustments the Comply foams gave the best combination of comfort, isolation, and sound signature. The worst went to the spiral dots which actually managed to make the Zs6 sound even brighter than it already was.


Then the Ostry tuning tips (OS-100, OS-200, OS-300) I had ordered to test with arrived from amazon. This series of tips going from blue to red to black introduces a filter in the barrel of the tip that cuts sound in certain ranges by as much as 6-7 db as seen in the chart below.




To my ears, the OS-200 tips allowed me to make the same correction I had previously made with the EQ with the tips and for those who are extremely treble shy, the OS-300 really brings that spike down. My go to tip for the Zs6 is the Comply foam or OS-300 as I think it does the best job of leveling the sound signature and gives the Zs6 a very natural presentation. It doesn’t hurt that the size large Ostry tip is a bit smaller than the size large KZ tip too and is a better fit for my ears.



It should also be noted that the Zs6 is low enough impedance to work when run directly from a phone but to really get the most out of them, you really need to amp them a bit. I ran them on a Schiit Magni 2 Uber, a Millett Starving Student (Poor impedance match and not recommended), a topping NS1, and Fiio E07k amps. When I attempted to use the Zs6 with the Millett SSH, I had a low level hiss in every track that was extremely distracting. Since I don’t usually test IEMs with this amp, I traded out a few other sets and found that most likely it is an impedance mismatch for anything below 32Ohms as it produced that same hiss with several 16Ohm high sensitivity IEMS. The Schitt Magni was a good pairing with the Zs6 and really helped open up the mids.

Comparisons:

Inevitably these are going to draw comparisons from the other products by KZ as well as other products in the similar price point. I have attempted to compare them with some of the other IEMs I have in my collection that fit one or the other of these criteria.



**** DT - the **** fits the class as it is a dynamic/BA hybrid with a sub $50 price tag. The **** suffers from some of the same issue as the Zs6 in that it needs EQ to do its best. Unlike the Zs6, that tuning is pretty heavy rather than just a slight dip of the treble knob. The Senfers also suffer from bass bleed into the mids and just cant muster the level of detail or the bass extension shown by the Zs6.

Mee Electronics M6 Pro - These fit the comparison only in that they are roughly the same price point. The M6 pro is a single dynamic driver with what I have to call the most analytically correct but boring sound signature of the lot. If you want an absolute analytical piece of equipment – the M6 pro is for you. If you are looking for a sound signature with any sparkle and life to it at all, you’ll find the Zs6 way more interesting. The Zs6 also seemed to be able to pull more detail out of the same DAP and flac file when compared to the M6pro.

KZ ATE - This is probably the headphone in the KZ line that started it all for most of us. The ATE was super hyped as punching way above its weight and being priced at sub $15. While some of the hype was just that, a lot of the praise lauded on the ATE was deserved. Unfortunately, the ATE has now been through a series of manufacturing changes and may or may not be the same model people came to love. On its best day, the ATE is still not capable of the treble extension of the Zs6, nor does it render detail nearly as well. As much as I love the ATE and it is still one of my recommended cell phone replacement headphones, it isn’t going to compete with the sound signature of most multi-driver in ears.

KZ ZST - KZs first dual driver IEM. The Zst has become a daily driver for an awful lot of us and is an extremely good value. That is not to say it is without flaws and a treble that is over-stated is one of them. The Zst manages to provide a very nice sound signature if a bit treble forward but does not have the sparkle, depth of sound stage, or bass extension of the Zs6.

KZ Zs5 – My Zs5 is the Version 1 with a single BA driver in the nozzle. I state this up front as my musings may not apply to version 2. The Zs5 has a similar signature to the Zs6 once the EQ has been applied to the treble on the Zs6. Having said that, similar doesn’t mean same. The bass clarity is not quite as good on the Zs5 and the extension on both ends is lacking when compared to the Zs6. Soundstage is a bit more crowded on the Zs5 as well. This is not to say the Zs5 is a bad headphone, it is far from it, just when directly contrasting it to the Zs6 it begins to show the evolution of the design.

Urban-fun hybrid - The urban-fun has been my recommendation for a good near neutral sound signature in the sub $35 range. I still think these are a solid recommendation in that space and they do have a more neutral signature than the Zs6. They don’t present the level of detail of the Zs6, nor do they have as good treble extension. Bass quantity also goes to the Zs6 as the urban fun just cant muster as much slam on bass heavy tracks.

One More Quad - Ok, so these don’t fit the price comparison. I add them here as this is another story of a company bringing out several headphones that punched above their weight (Pistons anyone?) and then creating a more upscale branding and product. I think we can draw plenty of parallels between the Xiaomi/One More and KZ when we look at Pistons vs the ATE and then the One More triple and quad vs the Zst, Zs5, Zs6 line. Granted the two brands are at different points on the curve, but we can see enough parallels to suspect we might know where KZ will go next. The Quad is a big deep V sound with good extension on both ends and a lot of detail in between. The Zs6 is a bit shallower profile but lacks a bit of the refinement in the sound signature of the Quad. If there is one thing the Quad could learn from the Zs line, it has an un-natural transition between the dynamic and the lowest of the BA drivers that can result in an incoherent sound. It doesn’t show up often, but when it does, it can’t be ignored. Truthfully, I don’t think the Quad is $150 better than the Zs6 and with that being the difference in asking price, I’d be hard pressed to recommend the Quad when you could buy 4 pairs of the Zs6 and have one of each color and a spare (or a few extra cables and tips) for the same money.



The Zs6 is an evolutionary step from the Zst and Zs5 and won’t surprise people who are familiar with the line. It does some things better, which shows KZ is learning and listening and it hints at things to come. At this pace, the Zs9 might just be ready to compete with the Shure 846 and the Westone w60. That is possibly the best news of all because it means price competition in the market and we listeners are the ones who win. In the mean time, if you haven't listened to a KZ lately, give them a try. You'll be surprised how much sound quality $50 will buy these days.



PS> Had a question on which Jethro Tull tracks I used - Hunter Girl and Locomotive Breath.