CCA Hydro (2DD + 8BA)

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CCA Hydro Review
Pros: -Build Quality

-Design is simple yet elegant

-Finally a better cable

-Tuning Switches are the best yet from KZ/CCA

-Very musical yet wonderfully technical

-Good note weight and texture throughout

-Very nice resolution throughout

-Big, impactful, punchy bass

-Melodic, detailed and airy midrange

-Treble is extended well with an open sound and good control.

-Big and open stage with good depth



-Very nicely detailed

-Great cohesion for a few 10-driver hybrid
Cons: -May be too large for some

-Some of you hate switches (con?)

-Possibly too much treble energy for some

CCA Hydro Review

CCA Hydro Featured Image

Full review can be found HERE

CCA Hydro Review


Hello, this review covers one of CCA Audio‘s latest iems, the CCA Hydro. The Hydro comes in at $115 to $120 depending on what options you choose at checkout. From what I’m told, the Hydro is to be considered one of CCA/KZ’s high-end flagship iems. I definitely wouldn’t argue with that considering the price. We’ve seen higher priced KZ/CCA iems in the past, but this has been the largest asking price since the KZ AS24 over a year ago. The Hydro is actually a 10-driver hybrid set consisting of two dynamic drivers and eight balanced armature drivers. I don’t know if any of you are counting but… that’s a lot. This may just be the most advantageous iem from CCA to date. You simply don’t see many 10 driver hybrids under $200. The fact that CCA was able to bring the price as low as $115 is pretty impressive. Actually, it’s pretty much unheard of. Ya know, KZ/CCA are both sister brands, which both work under the guise of crafting and creating the best audio possible for the least amount of money to the consumer. Call me crazy but I think the Hydro is a good example of this. So, I’m looking forward to checking this out.

A few reviews

I have reviewed a number of iems from these two brands over the course of the last few years. I’ve said it in many reviews that KZ/CCA seem to always get better. With every driver type, price point, and style, they get better. Eventually. It’s always incremental improvements and in doing so, they usually end up making some of the better iems you can buy at different price points. Here’s a list of some of the CCA/KZ sets I’ve reviewed recently:


AS16 Pro
PR1 Hifi
ZSN Pro 2
CCA Trio
KZ Symphony

Folks there really are a number of great sets listed above and each are the product of incremental upgrades, like I said. There are those who state that KZ’s iem production is akin to throwing spaghetti at a wall to see what sticks. I am not in agreement with this. I think KZ/CCA is very purposeful in their releases, and I feel they put a lot of work into making the best product possible for the least cost to the consumer. Every series within their enormous catalog of iems is a product of incremental improvement. Each one seems to upstage the last and usually the newer and better model will cost less than the previous, or so it seems.

The CCA Hydro

Well, I’m really curious about this set and looking forward to breaking it down. I want to see how well the Hydro stacks up against some other hybrids in its price point and above. I want to hear if the Hydro has what it takes to tote around the moniker “flagship”. So, I’ll give this set a good 50 hours burn-in and I’ll see you in about a week. The CCA Hydro everyone…

Non-Affiliated Purchasing Links:


I received the CCA Hydro from KZ as a review sample and in exchange I will conduct a full review and feature at I have not received any payment or any other form of compensation for this review. This set is a review sample iem. KZ/CCA has not requested to pre-read any review and doesn’t have any control over “what” or “when” anything gets published to All thoughts within this review are my own, though please take note that I will always have my own biases. This is impossible to get around. I try to be as objective as my subjective self can be, but this is an opinion piece folks. Thank you to KZ/CCA and thanks for reading.


Gear used
KZ AZ20 / Ifi Go Blu / Shanling M6 Ultra / Fiio Q15 / iBasso DX240 / EPZ TP50 / Hidizs S8 Pro / Aful Snowynight

Gear used for testing


Ifi Go Blu

-Hidizs S8 Pro Robin (not out yet)


Simgot Dew4x

iBasso DX240 with Amp8 MK2

Shanling M6 Ultra

Fiio Q15


Packaging / Accessories


Just like all KZ/CCA unboxing experiences, this really isn’t much of an experience. But also, who cares? KZ/CCA has long been known to put the money into the earphones themselves instead of adding a more elaborate box and better accessories. That said, they do provide a similar small black box as usual. Open that box and you’ll see the Hydro looking all handsome in foam cut-outs. Under the Hydro you’ll find the cable as well as the eartips and a switch tool. Like I said, not much to report here.

Hydro Packaging
Hydro Packaging
Hydro Packaging


Hydro Eartips

Within the packaging CCA provides four sets of tips in total. Three of those sets are the black KZ Starline tips (S, M, L). The other set is a pair of what I believe is a set of medium sized foam tips which come attached to the Hydro at purchase. Folks, I will always be a fan of KZ Starline tips. They are very good to have for any collection and I use them quite often. For those who don’t know, the Starlines are named this due to the Star pattern on the tip. What separates the Starlines are in their rigidity. They are a narrower bore eartip with a semi firm stem, firm flange and are slightly longer than most eartips. Great for really getting into the ear and sealing well. You get slightly attenuated treble, slightly boosted low-end as well. They really are great tips to have in a collection. For much of my listening I actually used the large sized Starlines. However, I ended up simply using the KBear 07 large sized tips after some time and kind of stuck with them. I feel the semi-wide bore of the 07’s does help the overall sound of the Hydro nicely.


Hydro Cable

Okay, so this is new. The package I received brought with it a big fat and juicy cable. Well, actually it is an option at checkout whether you want the usual KZ cable or the newer and more visually pleasing KZ cable. I was quite surprised actually. I say that because every earphone that I’ve ever received from KZ/CCA has been the same opaque white 3.5 single ended QDC style cable. It’s a decent cable in that it is a piece of the audio chain and does work. But that’s about it. I’ve said in every review that any set past ultra-budget would be great if we saw cables fitting to the earphones. Well, count me as surprised folks because CCA added in a fatty. Now, I’m not saying that this is the best cable on planet earth, but it’s a start. The cable I’m referring to is actually one of KZ’s own cables. There is no actual name, but it is very cheap at only $8 on Aliexpress HERE. At any rate, the cable is an 8-strand cable with 784 total cores, and it feels very robust for an $8 cable. Definitely an upgrade from the usual. KZ states that this cable is a silver & blue colored C-Pin or QDC style 2-pin cable, silver plated copper and it terminates in a 3.5 single ended jack. To get this cable the price jumps a little bit, or you could simply purchase the usual cable for a bit less.

What’d I use

So, for any 3.5 single ended listening I did use the better cable that came with the Hydro. However, I have a ton of balanced sources that I use and so it was imperative that I swap out cables for any of that balanced listening (which was most of the time). I used the KBear Show 4.4 balanced cable in white. Also, I used the cable which came with the Yanyin Canon as well which is also a gorgeous pearly white cable. Both did the trick quite well and I found the Hydro certainly responds to more power delivered through my balanced sources.


Build / Design / Internals / Fit

Build Quality

The Hydro actually follows in step the style of the CCA Rhapsody, both in design as well as build. These same design principles are also found in the CCA Trio. Both the Trio and the Rhapsody are tops in my book for best CCA earphones. In comes the Hydro. Now, CCA has a few different styles of earphones that they constantly use on repeat. They usually just switch up the design a bit. I’m referring to the actual shell style. The Hydro is identical in size and shape to the KZ AS24, KZ ZAT, CCA Rhapsody etc. Basically, they’ve used this mold on any set with a tone of drivers. It’s big! It’s very big. Smaller ear folks may want to keep looking, even though CCA does a good job with nozzle angle to help out as much as possible.

The build is made of a DLP 3D printed and tinted transparent resin shell with an alloy faceplate. Everything feels very robust in hand, very durable feeling. In my opinion, build quality is one of KZ/CCA’s strengths. They usually craft some hardy earphones. The nozzle is a longer nozzle, no doubt to get them as deep as possible. The nozzle width is roughly 6mm which is about average. On the back of the Hydro, you’ll see four dip switches which there are to switch up the sound to your own preferences. Also, there is a pretty large vent on the backside of the faceplate which does provide a nicely open sound. Again folks, one thing CCA does well is their builds.

Hydro Build
Hydro Build
Hydro Build
Hydro Build
Hydro Build

Full review can be found HERE

Tuning Switches

I never go very long into these tuning switches because it takes too long to describe something that you’ll play around with anyways. That said, CCA and KZ have been on a long kick now of adding dipswitches or “tuning-switches” to their earphones and I must say… they’ve only gotten better. Truly, their dip switches are some of the better switches I’ve seen, and they do make some noticeable changes to the overall sound quality. In top of that, KZ/CCA make their switches very easy to understand and use. I realize that many folks are sick and tired of the switches. To that I’d simply tell you too… maybe… not look at them. I don’t get the hatred, I really don’t. You can tailor the sound to more fall in line with what you enjoy. How is this a bad thing? Anyways, CCA makes it easy on us hobbyists and I’ll try to break that down for you now…

What do they do?

Tuning switches

Like I said there’s four switches on each earphone labeled 1, 2, 3 or 4. You can either push the switch up or down. For review purposes “on” will be represented as “1” and “off” will be represented as “0”. So, all switches on will look like this: 1111. Basically, the first two switches (1 & 2) add one “level” of bass each with the switch turned on. I’m assuming by “level” they mean about 1-2 db’s each switch by the way. The third switch brings the mids & highs up 2 levels and the fourth switch simply turn up the entire frequency making the Hydro a bit more sensitive and a bit more energetic.

Do they work?
I can see how adding switches is mindless and more troublesome than not when the switches don’t do anything productive to the sound. In spite of that, the switches on the Hydro actually make a huge difference. Quite literally you can semi-drastically change the entire sound signature. You can go from a basshead set with the switches at “1100”, or you can go with a more treble loving setting with “0011”. Those are the extremes, but I actually favor the setting “1110” due to the fact that the sound is more balanced across the mix with a healthy dose of every area of the mix. Still V-shaped and fun, but also technically very good too. For your info I did use “1110” for the entirety of this review. I will briefly discuss other settings at times as well but for all critical listening this is the orientation that suited me best. So, to answer the question in the header “Do they work?”, I’d have to say that yes, the switches do work very well, and you’ll find some of the biggest changes with CCA’s switches then you’ll find on most any earphone with switches.


I gotta hand it to CCA. I know that the Hydro has the same type of design theme as a couple other KZ/CCA sets, but the Hydro just looks premium to me. What a beautiful looking iem. The faceplates are shined to a mirror polish with a convex little wave going down the center. You’ll also notice the name “Hydro” imposed on the faceplate as well, written in a very elegant cursive. I really enjoy the look of this set. Like I said before, the CCA Rhapsody is very similar in design, but the Hydro is easily their best looking iem that I’ve seen. How cool is it that I can peer into the Shells and see the inner workings. Plainly visible I can see both DD’s, and I can see the four dual array BA’s as well. I can see the tubing too. I realize that I may be going pretty hard in this, but I have to give credit where credit is due. The Hydro is a very good looking iem in my opinion.

Exceptional Craftsmanship
Immerse yourself in luxury with Hydro’s high-tech DLP high-precision resin 3D printing and personalized light luxury appearance design. Its high-density lightweight metal material offers a delicate touch and stunning metallic texture.
CCA Promotional


Now we get to the interesting part…the Internals. Again, CCA chose to stuff 10 drivers in total into these gargantuan shells. That’s two dynamic drivers and eight balanced armature drivers. That is a very high number of drivers to try to coherently tune together. It certainly isn’t easy. Beginning with the DD’s, CCA chose to go with the much beloved 8 mm dynamic driver which can also be found inside of CCA’s awesome set, the CCA Rhapsody (Rhapsody Review). They also added in their equally enjoyed Xun-7 dynamic dual cavity dynamic driver which can be found in the CCA HM20. To be precise, that’s a 7 mm dynamic driver. As far as the balanced armature drivers, CCA went with the 31376 BA’s that they’ve successfully used a lot recently. There are eight of these balanced armature drivers and each is situated in a dual array setup. All drivers seem to be of a high quality to my ears. I’m no expert on every driver in the market but I don’t detect distortions and these drivers all maintain very good control too. Beyond the drivers, CCA added in a crossover and their four-way frequency division technology which obviously helps to partition certain areas of the frequency to certain drivers.

Professional Acoustic Hardware Configuration
Elevate your audio experience with CCA Hydro’s advanced hardware setup, featuring 2 dynamic drivers and 8 balanced armatures. This exceptional configuration sets a new standard in HiFi IEMs, surpassing the capabilities of traditional earphones.
Unrivaled Bass Performance
Dive into deep, powerful bass with Hydro’s specially customized dynamic driver units. Experience bass and sub-bass response that outshines conventional IEMs, delivering a truly immersive listening experience.
CCA Promotional

Fit / Isolation

Okay now this is a divisive section. This is not going to be an iem that anyone and everyone can get to fit right. It’s simply huge! Small ears should seriously take a 2nd look at the size. Again, just like the AS24 and others, the Hydro is large so that it can house those 10 drivers. One benefit is the longer nozzles as you can downsize your eartips if need be and shove em’ in a bit deeper for a seal. As far as I’m concerned, I feel the Hydro was built to fit my ears. I guess it bares mentioning that I don’t have huge ears and the Hydro fits so nice you’d think they grew there. Still, I know a few friends who had serious troubles with the AS24 and so I’m sure there will be just as many who have issues with the Hydro. Fit aside, I also detect very nice passive isolation. Obviously, the Hydro isn’t attenuating all noises, but for casual listening iems I’d say they are better than your average set of earphones.


Drivability / Synergy

The CCA Hydro is rated between 15-20 ohms depending on your switch orientation as well as a sensitivity of around 102 db’s give or take. What that means is that the Hydro is a pretty sensitive iem. Meaning, I can listen at good volume and dynamics even with a phone if need be. I know because I always check my reviews with my iPad just to check for sensitivity and the Hydro was easy to drive with it. So, I’m assuming you should have zero issues with whatever you use. Heck, I even used the KZ AZ20 many times out and about and I found this pairing to be much better than I would’ve thought. Actually, the AZ20 drove the Hydro with good headroom to spare, believe it or not. Those earhook Bluetooth adapters aren’t meant to be overly powerful so that was good to hear.

Beyond sensitivity, the Hydro also pairs very well with many different source tonalities. This is mostly due to the switches ability to change up the signature to match whatever source I’m using at any given time. If I use a cooler source than I up the bass switches and turn off the mid/high switch. If I have a warmer source, I can choose to turn off some bass switches and enable the highs. Pretty simple and it works. I feel the Hydro simply has one of those sound signatures which does well no matter the source. Also, the Hydro most certainly scales with added output power and obviously scales to the ability of the source. Basically, better sources mean better sound. Pretty self-explanatory.

Mobile Listening


For mobile purposes I mainly used the IFi Go Blu (CS43131 dac chip) using the 4.4 connection which was a great Bluetooth option for me. The slight warmth of the Go Blu and expressive dynamics played right into the Hydro’s strengths. Plus, it has a boatload of power for such a device. The EPZ TP50 (CS43198 dac chip) is an excellent source, as well as the brand new Hidizs S8 Pro (also uses the CS43131 dac chip) as both seem to mesh tonally with the Hydro in different ways. I find it very cool that the Hydro doesn’t really have a tonal color that it cannot at least sound marginally good with. The only caveat was the Fiio KA3. For whatever reason the KA3 just inflated or exaggerated the upper-mids through the treble giving the Hydro a more tinny or metallic sound and depending on the track it would come across rather shrill. Even a closer to neutral source device (dongle dac) like the Aful SnowyNight is a fantastic option using its wealth of output (300mw @32ohms) through the 4.4 jack and its CS43198 dac chips. Such a clean and controlled sound with really awesome detail retrieval. I actually have a blast picking a few songs and going through all my devices seeking out synergy and differences.

More juice

Now, when I use my more talented source devices it is pretty apparent that the Hydro does rise to the occasion. As it should. You have a better source sonically and you’ll likely have an earphone which reciprocates. There are three devices that I mainly use for my critical listening. Those being the Fiio Q15 (AK4499EX & AK4191EQ dac chips), the iBasso DX240 (ES9038Pro dac chip) with Amp8 MK2 attached and the Shanling M6 Ultra (AK4493SEQ velvet dac chip). Each one gives its own flavor and each one created nice synergy. I suppose for me, if I had to choose one that I feel really synergizes in audio euphoria per my particular tastes, I’d say the Shanling M6 Ultra is that device. What a silky, milky, and altogether resolving sound these two marry with. Just awesome. However, the other two which come across closer to neutral offered a fine contrast with the Q15 sounding ridiculously technically savvy with the Hydro attached.

What do you need?

I would think that whatever you have on hand will likely work. Just know that the Hydro does scale to a degree with amplitude, or power (in my opinion), and it does reward a more polished source. In most of my reviews I will usually tell you all that a decent Dongle Dac would suffice (with most iems anyways), and I would say that for the Hydro as well. All you need is a decently powerful dongle dac. I realize that we all have different financial situations, and some folks will only be able to afford the Hydro and the Hydro alone. So long as you have a 3.5 jack that you’ll be in business. If you can muster up a little bit more and get a $40-$50 dongle dac like the EPZ TP20 Pro for instance, it will be a drastically improved listening session from most smartphones (not named LG). I really enjoy the TP20 Pro (Review soon) with this set.


Sound Impressions

Note: I want to preface this entire section with a couple things. I did burn the Hydro in for about 50 to 60 hours. I simply put it in my burn-in station and let it play “burn-in” tracks meant specifically for this purpose. They provide white noise, pink noise as well as many different looping tones which range throughout the spectrum, and I play those on a loop for days. I did notice that the bass tightened up. Of course that could just be me dreaming that up. But it did seem to have an effect on the transient response of the low-end. Also, I only use flac or wav files which are saved to my devices for any critical listening. I primarily listen with the UAPP app which is downloaded on all my devices as well as Hiby Music and Poweramp (at times).

No hype…

The CCA Hydro seems to me to be the culmination of years of tinkering on KZ/CCA’s part. Years of hybrids within the budget sector have slowly and incrementally evolved into what I have before me now. I’ll just get this out of the way so that there’s no confusion; the CCA Hydro might just be the best hybrid iem that they’ve ever produced. It’s a fine set folks. I do believe the Hydro can and will compete with most hybrids within its price point ($100-$150). I didn’t say it’s better, but I did say the Hydro can compete and I’m sure that some would take that conservative statement even further. I’m not making any grand proclamations here, I’m not saying the Hydro punches above its price (it does… lol) or is the greatest thing since the invention of earlhones. I’m not doing that. This isn’t a hype piece folks. I’m not into that. I’m simply saying what I hear. This is a fine set.


The CCA Hydro comes across with very nice timbre for a 10-driver hybrid with a warm hue against a neutral canvas. The low-end & the treble region are emphasized no matter your switch settings. The tonal color of the overall signature does depend to some point on what switches you use. I told you I’m using (mainly) the “1110” setting. To my ears this setting provides a warm/neutral sound but tilting more towards the left (warm). I hear a very well-done V-shaped sound. Using the switches will change up the sound enough to make a noticeable difference in the overall listening experience.

The Hydro comes across with a good balance of smooth and crisp. Macro-dynamics have good energy on the Hydro as well. The Hydro does have a heavier presence down low, more full sounding and weighted. Hydro also has good energy and sprightliness towards the top end as well. Note weight is pretty nice too. There’s a certain richness to the sound while still feeling open and separated for instruments and voices. Transients are generally tight enough to cleanly contour most notes past the bass region and resolution is nice. It’s a pretty clean sound. Nothing grainy or muddy to my ears with “1110”. Possibly the more bass heavy settings can get a bit too full or bloated for some, but for the most part I don’t hear that. Furthermore, the Hydro doesn’t shy away from the technical stuff either as detail retrieval is very nice and imaging is nice too. The stage is big, round, pretty deep for a $120 iem with evident layering ability.

Condensed Sound Between the 20’s

Starting with the bass. The Hydro can absolutely BANG! No doubt about it. Can the Hydro become a basshead set? It can get close I suppose. Yet using my favored setting (1110) I hear a very mid-bass focused sound, punchy too, with decent extension into the lowest of lows. Timbre is great down low with good transient swiftness per the tuning.

The midrange has a nice lean-lush note body with a slight intrusion of the bass into the lower mids. There is a very slight recession in the low mids but they come across with good enough energy. The upper-mids are certainly the focus here. Female vocalists sound awesome with good tactility and instruments have a fine lined note definition that is both transparent and shimmery. The treble region does not lack energy at all. This is a vibrant treble that is very nuanced and textured. While smoother in the note body there is still a good bite and micro-dynamic control as detail retrieval is quite good.

Treble transients have a tight attack through release sounding energetic and full of pep. Extension is pretty darn good too. Now, at times the Hydro may come across a bit too bright for some, maybe a slight bit too shouty or shrill depending on your switch settings. Still, when I use the “1110” I do not hear that nearly as much as the brighter switch settings. The graph below shows the “0000” setting for reference, sorry I do not have a graph with every switch setting.

Graph courtesy of OB Odio, Thanks!


Bass Region

It Bangs!

The first thing I’d say about the bass region on the CCA Hydro is that it can flat-out GET-IT! It’s emphasized quite a bit with a big pregnant hump cresting out at the mid-bass and spilling over into the midrange adding a slight warmth. Like I said earlier, this set can bang! With a 9-12-ish dB bass shelf (depending on settings) the low-end carries a good amount of weight in any switch orientation. That said, using my favored switch settings I found that the bass is offset a bit better with the treble region, leaving a less bulbous bass than other settings. This is a low-end which can go from just shy of basshead, to pretty well balanced and everything in between. Certainly, on the heavy side which will provide heavy kick drums, bass guitars, synth, and provide some very meaty and fun bass drops.

CCA Nailed it!

I should also note that for the size and emphasis of this bass region… it isn’t sloppy at all. I hear very good tactility, texture and a clean impact. Perhaps a little soft at attack at times but not sloppy. The Hydro has very clean notes, clean hits, resolute and on point. The bass has a snap to it. Also, decay is on the tighter side of atmospheric, if that makes sense. Meaning, you have this forceful attack with a slightly lingering decay which I tend to enjoy. You can tell this is a good DD impact and decay. The body of the notes are dense, centered and authoritative, and the initial attack at the crest of a note seems to have a relatively hard snap to it. The Hydro has a controlled slam listening with the Hydro. There’s good depth in the bass with well-done layering of sub & mid-bass notes. Honestly, for a larger bass section, I think CCA really nailed this tuning down low.


The sub-bass comes through with a rigid and concrete-hard lower bass drone which gives off some nice haptic reverb and vibration. It’s certainly a physical bass and it really shows up on tracks which cater to that. Yet the sub-bass isn’t intrusive at all and doesn’t spread its influence past the bass region to an annoying degree. At least for me. It’s kept clean and tidy on the Hydro, which is really nice to hear. You find that on tracks like “Mancey” by Andrew Bird. You can hear it right at the outset of the song, it’s a low droning, air-moving, and sonorous bass guitar which serves as the foundation of the track. The Hydro doesn’t mince words here. It rumbles deeply and with nice sounding density (if you’re into that). Having said that, the sub-bass doesn’t really veil, cast a shade, or bloat the midrange. A cleaner approach against the deep rumble. It’s pretty well done. Also, the sub-bass is not the focus of the low-end as far as emphasis is concerned. I would never say it’s rolled off, but there’s a mild downhill slope from the mid-bass. Still, I don’t feel that anything lacks at all. Listening to “Heavy is the Ocean” by Bush it’s very apparent just how deep the Hydro can represent my music. This is a track that grumbles and growls right away progressively getting more intense and carries this deep pitched and solid rumble all the way through to the main verse. Like a lead-in almost. The Hydro doesn’t let me down and adds a tactile and convex type of guttural and very sonorous bass.


This is an area which slams with some good force on “1110”. Who am I kidding, it slams with any switch setting. Again, this is a more pregnant mid-bass that is kept pretty darn clean and doesn’t muddy up any other area of the mix at all. It’s hard to not at least be semi impressed here. The mid-bass notes never feel too muddied or too slow in my opinion. For me that is. You may feel different. Which isn’t the easiest thing to do with a more emphasized bass at $120. Granted, it’s not unheard of either, it’s just nice. Perhaps with the heavier bass settings you’ll have a slightly muddier experience, but in the “1110” I hear a pretty clean sounding low-end with a heavy but also concise thump and slam.

Mid-bass cont…

The track “All Night” by Big Boi (former Outkast member) has a very reverberant steady bass drop and the Hydro sounds really great. It’s deep, textured, and keeps the midrange almost untouched apart from some warmth given. Big Boi’s voice seems unsullied from the bigger bass section. “Privileged Rappers” by Drake is another track with a very concise, clean, and robust bass. “Peace and Love” by Red Hot Chili Peppers has some of the deepest bass guitar and the Hydro shows off on this track a little bit. Very deep in its pitch with good control. The Hydro is ductile in the way it portrays each undulating bass guitar groove, without sounding compressed or flattened. “Move Along” by the All-American Rejects also shows off the Hydro’s abilities with this track’s thundering kick drums. I hear a nice tacky wet egde on the initial strike followed by a cavernous hollow boom. This track has successive kick-drums beats and each one is satisfying. If you like a slightly bigger bass than I’d suggest at least looking at the Hydro.

Downsides to the Bass Region

Obviously, anyone who detest a larger bass section will probably not want to take part in the Hydro. It is a very much emphasized bass region although I don’t feel I hear exactly what the graph indicates that I should hear. At any rate, some folks don’t want that bulbous and rumbly bass and would rather have a tight and contoured BA style low-end. I get that. I could also say that in some switch orientations you will hear a slightly muddier presence. What I mean is that you don’t always have the counter of a more emphasized treble region with some settings like “1100” etc. Having said all of that I do want to state that I never consider this set a basshead iem. The graph shows this very convex hill within the mid-bass, but it never shows itself that excessive in real-world listening. Not to me anyways. The Hydro simply has very nice bass and a quality bass for an emphasized low-end. But I don’t consider this a basshead set. So bassheads may want to pass on it. Beyond that I think that most folks will be able to appreciate the low-end here and what these dual drivers can do.



The mids come across very well. No this isn’t some vocal-centric iem that will astound you with its ability to put vocalists on a pedestal. It isn’t quite that. This is a V-shaped set. Still, the midrange is very clean and very resolute. Even with a “slight” low-mid recession, I still hear a well highlighted and open sound. Never really foggy or veiled. Instruments are pretty much on point and imaged well, separated well and even crisp. However, it isn’t the type of “crisp” that sounds edgy or metallic. This is a clean crisp attack with a smooth body to notes. Note weight is a very nice version of lean-lush. There isn’t any extra fat on the bones, if you will. But at the same time each note does have a certain solidity to them. The midrange is also nicely detailed and nice resolution with good cohesion and good cadence for a set costing $120-$130. I hear nice vibrance throughout as well with a transient response that is pretty precise without sounding thin, anemic and analytical to my ears. Harmonics hang around just long enough but never overstay their welcome, so to speak. Also, timbre is close to natural. You still have that slight “balanced armature timbre” to a degree. Yet on the Hydro I really don’t hear that as I usually do. Granted…it’s there, but simply not an annoyance or a “con” for me. There’s an open and airy sound within the midrange with obvious layering as well.


Males come across pretty spotless in their note definition. Partly this is due to the low-end precision and the sanitized nature of the spectrum as a whole. Like I said, there is the slightest recession, but that recession doesn’t really come across as pushed back. It just isn’t as vibrant as the rest of the midrange. Males still have good note body. Not thin by any stretch of the imagination. They are a speckles version of warm, which is very good to hear. Again, I don’t want to come across as though I’m hyping this set to the moon, but it’s refreshing to hear a good hybrid sound that actually does compete with some of the better iems in the price point. The lower-midrange has a nice part to play in that.

Low-mids cont…

Tracks like “Rome” by Dermot Kennedy is a great example of how his voice cuts through so well with a nicely defined note structure and body. His voice is already harder and not as soft. His voice is edgy and composed and so the Hydro really creates a nice clean note edge in his vocals. What I like is that there is actual body behind his voice. The song “I Am the Highway” by Audioslave features Chris Cornell‘s (RIP) melodically raspy and gritty voice wonderfully. So many sets can and will lose their control with his voice. They’ll lose that edge. Grain and fuzz will be introduced into the sound at the outline of his vocals. However, the Hydro doesn’t really do that. This may be in part because of the warmth and body and smoother undertones. Even so, the Hydro does do those crisp inflections to his voice very nicely too. Instruments in this region sound natural and I didn’t hear anything which sounded off about them.


The upper-mids are where I feel that the Hydro excels the most within the midrange. This is a highly resolved upper midrange. However, that high resolution doesn’t steal the emotion from female voices like some sets can do. Basically, the Hydro didn’t necessarily have to sacrifice note body to get that resolve. It isn’t anything even close to analytical but the upper mids are transparent and highly detailed. Females like Rachael Scott from the band Lake Street Dive sound absolutely gorgeous. Obviously, there are sets which can pull off female voices better, but remember, this is a V-shaped iem here. Not vocal-centric. Anyways, in the Lake Street Dive track “I Can Change”, Rachael’s voice is simply beautiful. Her voice comes across full & open sounding with this lush vibrance against the rest of the melody. Perhaps some folks will feel that the upper-mids are too elated or shouty for them, but not me. Maybe those sensitive to upper-mid shout I suppose. The track “Stampede” by Jess Williamson is another example of a vibrant sound and a well delineated voice. Almost highlighted. Instruments around her voice don’t come across stuffy or too complicated. Tonality and timbre may be a bit less natural but not bad by any stretch. The layering in this track is nice as well. Front to back there is a 3d style depth to the song which is good to hear.

Instruments in the midrange

Instruments in this region don’t always come across perfectly naturally. Let me just start with that. Of course, I really enjoy how they do come across, but I figured it made sense to at least speak in that. Also, it isn’t like instruments (and voices for that matter) sound wholly unnatural either. That said, instruments also are very precise and pinpoint in their separation and imaging with good air between all instruments while they also come across highly detailed in my opinion. Stuff like finger slides on a guitar, breath on mics, different harmonics etc. They’re fairly easy to pick apart for me. Honestly, I don’t hear anything strident or metallic. Nothing too knife edged or grainy either. Strings have that controlled edge to them. Violin generally can sound anywhere between silvery and mellifluous. Piano has that harmonious tunefulness with nice weight to each note (depending on the track of course). Percussive instruments all have a certain snap to them. Good crispness at attack. Whether it be snares, cymbals, bass drum, triangle, they all have that last little bit of extra energy to make them pop. Instruments generally sound nice. I won’t sit here and map out 100 different examples as that is too much for anyone. But I will say that nothing is so out of whack that it’s a problem.

Downsides to the Midrange

One thing I would say off the bat is that the timbre isn’t perfect throughout. I should say that this is to be expected in a KZ/CCA set. However, I really don’t think it is as apparent as many sets from the brand. Having said that, this really isn’t an issue for me as the sound is still musical and very clean. Also, many sets from many brands display this with balanced armature drivers. Also, the midrange may be too bright or shouty for those sensitive to it. I know plenty of folks who would much rather have a warm to dark sounding midrange with an even richer note body. So, I could see how some wouldn’t really dig this set. Other than those two subjective issues (not really issues) I feel that the Hydro does a great job of balancing the technical stuff, resolute, tight transients, micro-dynamics, details, with at least some good musicality and emotion. Basically, KZ/CCA have come a long way in their balanced armatures and the tuning of those BA’s. The mids are nice.


Treble Region


The highs on the CCA Hydro can go from very bright to fairly bright depending on your switch selection. Using “1110” I don’t find them too piercing for my ears. In fact, I feel the treble fits the overall tuning very well. This is not the most crisp or crunchy treble I’ve ever heard, but it is very well detailed. I hear a smoother treble yet with very good transient attack through release. At least that I can tell. This is a nicely brilliant treble with very good energy, it’s sprightly, vivacious, and nicely controlled in that energy, it’s good. Of course this is my definition of “good”. I could certainly envision other people (who don’t want a brilliant and emphasized treble region) not thinking it’s very “good”. That said, I don’t feel this is one of those forced resolution situations either. Like I said, the treble fits the overall tuning scheme here with an appropriate level of emphasis that counters the bass region well. Of course, you can dial that in to better suit your tastes a little bit with the switches. I really don’t get that raucous or shrill sound from this set up top. I don’t hear anything shouty or too harsh. Side note, there is a slight metallic edge to notes in the treble region. Nothing that is bothersome to me, but I’d be remiss if I didn’t at least bring it up. Anyways, as far as the actual level of emphasis is concerned, I think the Hydro will fit many folks’ ideal brilliance. Again, you have switches to make some changes if you’d like.


There’s a refinement in this treble region which shows it face in the bite you get in each note. Now, I am in no way comparing this to much more expensive sets which perform even better. Nor am I saying that the treble equals better driver tech like EST drivers for example. I think my praise comes from the fact that KZ/CCA seem to have really dialed in their approach in his set. Think of all the KZ/CCA iems and on many of them the main complaint will be the treble region. So much so that when a set like he Hydro actually sounds refined, controlled and cohesive, it is something to talk about. The truth is the treble is pretty well done. You’ll notice many sets dial back this region on purpose. It’s better to have a decent warm to dark treble than to have a shrill and piercing treble that is hard to control. The Hydro seems to have done well in this regard. It is brilliant and treble notes do have that subtle bite. Details are easily illuminated and there is good spacing between instruments.

Speedy treble

This treble region is most certainly one which can handle complicated tracks rather easily. Especially when I listen with something like the Fiio Q15. Those two coupled together can take on most anything. Listening to Billy Strings in the track “Ice Bridges”, the Hydro literally hits every note with good separation to my ears. His tracks feature rapid fire banjo, mandolin and guitar play and Ice Bridges is no different. The Hydro truly stays at pace with this song very well. I use Billy Strings as an example often to try I get a sense of how review sets can handle those fast and precise notes without blending or meshing together. The Hydro does well folks.


Extension is also very good on this set. The upper treble misses almost no info at all and does so with a relatively good timbre to my ears. Of course, nothing is perfect, but I don’t hear splashiness from the secondary harmonics of a cymbal strike for example. Listening to “In Bloom” from Nirvana you’ll hear those defined cymbals crashing away and the Hydro really does keep a good body, they aren’t just a mess of treble sheen, and they stay fairly well controlled. It isn’t just cymbals though. There is texture in the upper treble (basically all the upper treble is), there’s air and openness in the upper treble and it isn’t artificial to my ears or glassy like so many sets can sound like. For example, the upper harmonics of an electric guitar sound intact and energetic without coming across shrill to my ears. Violin close to this region has that edge and tactility. So yes, the extension is pretty good and does well to complete the sound when listening to my music.

Downsides to the Treble Region

Of course, the biggest drawback of a larger emphasis of the treble region will be for those folks who cannot handle it. Some people are very sensitive to treble brilliance and brightness. Granted, I wouldn’t necessarily call the Hydro’s treble super bright, but even so it may be too much for some hobbyist’s ears. I understand this completely. I had to basically grow into enjoying a bright treble. Now I can very much appreciate it. Some people I know, audiophile people who really enjoy a good dark treble region. Treble that still has that highly resolving sound and treble punch and bite but simply comes across less enthusiastic. I feel that brightness is probably the most polarizing aspect of this set.


Full review can be found HERE



Folks, the soundstage is very well laid out. It sint some coliseum or stadium in my ears. It’s above average though in width and has a tall presence too. However, what I thoroughly enjoy is the depth of the sound field. CCA did a good job of creating actual layers to the sound. A psycho-acoustic front to back rendering of the sound which absolutely brings in an almost 3D sensation. This will vary by the recording, but the Hydro does have that sense of depth which to my ears is great to hear.

Separation / Imaging

Another string point of the Hydro’s tuning comes in its control over the spectrum. This control is a huge contributing factor in its ability to separate elements of the stage. Instruments and voices both seem to be well compartmentalized and delineated. Obviously, this can all derail on a poorly recorded track or a highly complicated track. However, for he most part the Hydro does very well. Transients are tight, the sound is very resolving and clean, the stage is nicely wide and deep too. Each of these attributes helps instruments to sound as though they have their own little space, partitioned off from the rest of the instruments and vocals. The same can be said of the Hydro’s ability to image the stage as imaging is pretty much pin point in this set. Layering is nice as well.

Detail Retrieval

When listening for the minutia within my music I rarely had any trouble with the Hydro. Perhaps this is close to the most technically adept iems that CCA has ever produced. I know that is an easily debatable thing to say. Still, the Hydro really does bring out the subtleties in a nicely refined way for the price. Really bass heavy tracks may mask things to a degree and tracks featuring a ton of treble activity may as well. Though for the most part I’d say that the Hydro is certainly a very good detail set. Is it the best in the price point? No, I don’t think it is. There are iems around that price and even under the price of the Hydro which are quite literally tuned to be technical beasts. That said, the Hydro does a very good job at detail retrieval. For all the reasons I outlined in the “Separation / Imaging” section before this the Hydro does a fine job.


CCA Rhapsody / CCA Hydro / Hidizs MS3


Note: I simply want to preface this section by explaining that these comparisons are not to establish which set is best. It is not a duel of the death. That is unhelpful to everyone. Plus, everyone is different in so many ways. The best I can do is try to establish some differences as best I can. Also, I am only speaking in very general terms. I am not going to go too in depth either as I do have to watch my word count. This is always a problem for me.

CCA Rhapsody ($68)​


The CCA Rhapsody (Rhapsody Review) from the same brand as the Hydro is truly a special iem at its price point. Easily one of the better iems you can find at its price. Heck, there are times you can find the Rhapsody for as low as $48. A truly special deal for what you get in return. The Rhapsody is a hybrid iem consisting of dual dynamic drivers and four balanced armature drivers. Folks, I really gave CCA it’s props for that set. An easy recommendation. This is a set which came hot on the heels of a string of very good sets from KZ/CCA. I realize it doesn’t make much sense to pit the Rhapsody against the Hydro, but I do think it may help some people to understand the Hydro a bit better because of it.


Aesthetically there really isn’t much which separates these two. They have the exact same mold of their shell. Exact same size, exact same shape, exact same nozzle length and width. The design is slightly different, but the materials are exactly the same. Same high polish faceplates, both have a minimalist approach, both have their names written in elegant cursive, both have a transparent housing, and both have four tuning switches. Obviously, the Hydro has the better cable but that’s only if you purchase the package with the better cable. Other than that, there really isn’t much difference thus far. Obviously, the driver configuration is similar but of course the Hydro has four more balanced armature drivers and the DDs in the Hydro are better. The Hydro uses the Xun-7 driver which is a quality DD along with the same 8mm driver as the Rhapsody. So, there are many similarities.

Sound Differences

Between the two the Hydro isn’t as warm as the Rhapsody with better note density across the mix and a more 3d style stage as well. The Hydro has a little bit more of a crispness to it whereas the Rhapsody is basically smooth at all times. The bass region hits a hair deeper and with a slightly more weighted boom on the Rhapsody. Though the Hydro has better clarity, definition, as well as a faster bass that can handle more while also having better control. The Hydro’s midrange has a much cleaner sound altogether with better detail retrieval and transparency. Rhapsody has a leaner note body and feels more recessed to the Hydro’s faster transient response but also more dense note body. Also, the Hydro has a bit more shimmer and vibrance in the upper midrange. Both sets have a nicely extended treble region, but the Hydro is certainly a step up in this regard. Hydro has more defined treble notes and details arise easier on the Hydro as well. Honestly, the Hydro is truly a step up in almost all ways. Unless you yearn for a slightly more bass heavy sound.


The Hydro wins out almost across the board here. Whether it be separation of elements of the stage, Imaging of those elements. The Hydro comes across with cleaner and more rapid transients throughout. Detail retrieval is simply better on the Hydro too. Lastly, the stage is close on both of these sets as far as width and height is concerned. However, the depth of field is better on the Hydro.

Further thoughts on this comparison

As if I thought this would go any other way when I set out to actually compare these two sets. It was very one sided to be honest. The Hydro simply has the more coherent replay while also having four more drivers on each earphone. It has better control over the frequency and the Hydro comes across with less of a metallic tinge in the upper portions of the midrange and treble region. I really do enjoy both sets and these differences are minor. However, we pay a lot of money in this hobby for small differences. Honestly, the Hydro is simply the more controlled, coherent, and polished iem. As the cost difference would suggest.

Graph courtesy of OB Odio, Thanks!

Hidizs MS3 ($120)​


Okay, now this is a much fairer comparison. I chose one of the best hybrid iems that $120 can get you in the Hidizs MS3 (MS3 Review). This is a set that really does compete well against any and every iem within its price point. The MS3 is a three-driver hybrid with a 10.2 mm dynamic driver covering the lows and mids and two Knowles balanced armature drivers taking on the highs. Hidizs really did a great job on this set, and it is a great one to just chill with and enjoy your music. They used quality drivers; it has a quality build and quality tuning was done to make a fantastic iem for the price.

Starting with the build, the MS3 is built like a tank. Made entirely of alloy it is simply built better. Not to take anything away from the Hydro either as it’s built very well. The design is different. It’s really up to you to decide what it is that you like better. For me I do enjoy the design of the Hydro better but the MS3 is a dope look too. Both are slick looking in my opinion. That Hydro is just elegant though. Internally, the Hydro has many more drivers to occupy the different areas of the spectrum which should be a major advantage. Still, Hidizs really uses quality drivers in its Knowles BA’s as well as its beefy DD. Without question the MS3 comes better equipped. Much better tips, much better cable, it has a pouch too.

Sound Differences

These two sets have a lot more similarities about them than I originally suspected. It wasn’t until I spent about an hour comparing them that I noticed those similarities. The Hidizs MS3 is easier to drive by a small margin, better for less powerful sources. To be honest, both sets are a hint warmer than neutral with the Hydro coming across just a bit warmer. Extension is better in the Hydro both ways to my ears. The bass on the Hydro is deeper, more robust, and also a bit better layered. While the MS3 has the tighter low-end, more defined. Also, the MS3 only has a hair less weight in this region. Mid-bass is just much more pronounced in the Hydro. The midrange of the MS3 is leaner, less solid in its note body while the Hydro carries just a touch more weight. Both sets have that slightly recessed low-mid with a more vibrant upper-mid. However, the Hydro is a bit more resolute, detailed and does have a touch better control over the mids. I noticed the MS3 has a slight bit more of a tendency towards sibilance. The treble region of both iems is energetic and extends well. However, the MS3 simply doesn’t have the resolve of the Hydro. The Hydro has better detail retrieval. That said, the MS3 has better timbre up top with less of a chance for harshness. I would say that the MS3 probably has the better timbre overall in fact. Closer to natural I would think. The Hydro has more energy across the mix too.


Looking at the soundstage, the MS3 is slightly narrower and has less of a 3d type stage featuring less depth of field. The Hydro has more of a holographic sense and does have better layering. Details retrieval is better on the Hydro, once you get past the bass region that is. Both sets offer good instrument separation, but the Hydro does edge out the MS3. Imaging is the same, both are very good for the price. Transient attack through decay is quicker and cleaner on the Hydro while the MS3 is more atmospheric to my ears.

Further thoughts on this comparison

I realize this looks pretty bad for the MS3, but honestly these two sets are much more alike than they aren’t. Even with 10 drivers against 3. I think timbre-wise the MS3 probably wins out along with low-end but in every other aspect the CCA Hydro does out duel the MS3. That all said, I truly enjoy both iems for what they are and have a great time listening to both.

Graph courtesy of Hi-End Portable, Thanks!


Is it worth the asking price?

I always hate answering this question. To be 100% honest with you all. I basically only review stuff I enjoy and so the answer to this question will almost always be yes. Unless something is drastically overpriced. However, most of the time it’ll be yes, because I like it. Still, I hate answering a question for you when the answer to this question is for me. Without question the CCA Hydro is worth every penny of that $120. Of course, there are some very nice hybrid iems at its price point and so there may be some sets which suit you better. That +$100 price point is a tough one. You have sets like the Simgot EM6L (EM6L Review), Kiwi Ears Quartet (Mahir’s Quartet Review), Fiio FH3, Sound Rhyme SR5, Juzear Flame, Celest Phoenixcall (Phoenixcall Review), Hidizs MS3 (MS3 Review), Rose Technics Star City 5 Pro (Star City 5 Pro Review), Tinhifi T5S (Sean’s T5S Review), Letshuoer Gizaudio Galileo (Mahir’s Galileo Review), among many others and yes, I know I left many out. That said, it would be hard to find anything that has even close to the driver count (not that driver count equates to good sound) of the Hydro. Also, you be hard pressed to find a set that is outright better technically as well. For me, the answer is a resounding yes.

The Why?

Because the CCA Hydro is equipped with 10 drivers in total, and it is the culmination of many years of trying to get this hybrid thing right. The Hydro is built very well and has a very minimalist but slick design and will look rad in your ears when out and about. Yes, the packaging and accessories aren’t the best, but you can pick up the better cable for the Hydro which is nice I suppose. Still, the real worth is in the sound and the sound does not lack on the Hydro. Truly this is a very good hybrid set. I’m not saying there aren’t some fantastic hybrids around its price point, but the Hydro does excel in many ways. You have that big, fun and deep bass that is well controlled and clean with good depth. The midrange has nice note weight and is very well detailed, separated well, and images very well too. The treble is sprightly, has nice brilliance, with very good upper treble extension and can handle just about anything you throw at it. Details come out of the woodwork with this set in my ears and resolution is very high across the mix. I’m not trying to convince any of you but for $120 I think this set is fantastic. Yes, the Hydro is worth the asking price.


Ratings (0-10)

Note: all ratings are based upon my subjective judgment. These ratings are garnered against either similarly priced sets or with similar driver implementations or styles with the unique parameters of my choosing. In the case of the CCA Hydro ratings below, that would be $100 to $150 hybrid driver earphones. Please remember that “ratings” don’t tell the whole story. This leaves out nuance and a number of other qualities which make an iem what it is. A “5-6” is roughly average and please take into consideration the “lot” of iems these ratings are gathered against. $100 to $150 is a smaller sized scope of iems yet it is very competitive. However, it’s also a small enough pool of iems that seeing a “9.0” for example, shouldn’t be too amazing to see. My ratings are never the same and each set of ratings tells a different story. Each time you read one of my ratings will be unique to that review. Basically, I create a Rating that makes sense to me.


Build Quality: 8.3 Built well but not tops in class.

Look: 9.0 Clean, fresh, simple, elegant.

Fit/Comfort: 8.9 Fit and comfort is great for me.

Accessories: 6.5 Accessories isn’t CCA’s strong suit.

Overall: 8.2🔥🔥

Sound Rating

Timbre: 8.9 Great timbre for a hybrid.

Bass: 9.3 Deep, robust, impactful.

Midrange: 9.0 Resolving, detailed, dynamic.

Treble: 9.3 Extended, detailed, precise.

Technicalities: 9.7 All technicalities are great.

Musicality: 8.9 Nice mix of musical and technical.

Overall: 9.2🔥🔥🔥

Ratings Summary:

To summarize the ratings above I decided to only include hybrid iems between the price of $100 and $150 US. I figured this rating made the most sense for anyone seeking out a hybrid set. Hopefully it’s helpful and if not then please comment. I never know if these ratings help anyone at all. You all know how I feel about ratings, they stink. They leave out nuance and rarely tell you anything useful. Looking at each rating I don’t see many that I feel I would have to argue against. Which is rare. Usually someone from the peanut gallery will chime in with his or her complaint. Oh well, such is life. We are all so different and how we perceive music can be drastically different among about a hundred other variables. So, as always… Grains of salt.

Explain Yourself!

Honestly, I don’t feel there is really a Rating that is very controversial here. If I were to pick one that may get some eye rolls it would probably be “musicality”. I gave the Hydro a “8.9” in musicality. I actually had a hard time with this one. By the way, musicality is a dreamt-up word which has no quantifiable standard and can mean just about anything to everyone. That’s it. It’s another ridiculous audiophile term that we like to think is an across-the-board understanding. Musicality to one may be polar opposite to musicality for another person. So yes, this is a Rating I could see someone thinking I’m crazy. Some folks think of musicality as though it has to be warmer sounding, less analytical. That makes no sense. Others feel that the word musical means the opposite of that…Yada, Yada, Yada. Folks, this is a subjective game, and we are all right 100% of the time. Beyond musicality, I suppose some folks may get on me about the “midrange” rating. Maybe its timbre isn’t organic enough for some, or maybe the midrange isn’t warm enough for another. Who knows. That’s about all I got though. This is a good set from CCA folks.



To conclude my full written review of the CCA Hydro, I must first thank the good people of KZ/CCA. Thank you very much for always letting me do my thing and never asking me to tilt my words in a more favorable direction towards your products. I have always had a good working relationship with this company because they let their products speak for themselves and when the dust settles, they don’t run even if I give a not so good review. I respect that quite a bit. So, no matter how you feel about the brand, I have no qualms with them. They make good products.

Different Perspectives

Friends, please check out other thoughts of the CCA Hydro. We are all very much different as each one of us has our own ideals, likes & dislikes. We all have different gear, different hearing abilities, and we all haven’t been down the same journey through audio. Each of these can completely skew our thoughts for any particular product. It will be very beneficial to you if you just click a few more links. Don’t simply rely on me. I’m only one man and while I do give you my absolute most honest take, the next guy may feel entirely different. So please check out other thoughts about the Hydro. I think I’m done folks. I hope you all are well and good. Please take good care, stay as safe as possible and always… God Bless!

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@dezzadk, With higher volumes I do not get excess treble harshness. In fact, I feel the Hydro actually gets better with higher volumes. Of course, I am a higher volume listener. Probably something I should remark about in my reviews. So the bass is really very nice. I try not to make any grand declarations about how good a thing is but I could see how Akros came up with this. No this is not the type of bass that will color the whole of the spectrum, add unwanted veil or become muddy in the right switch settings. Of course, some would probably argue that, especially if they are allergic to bass. Great for techno, edm, and any other genre which requires a deep, palpable and snappy bass region. It isn't sloppy at all.
@dezzadk, Now, if you choose the more bass heavy dip-switch settings than the bass will color the spectrum a hair more, but for the most part the bass is clean. I didn't know he compared them to the Top. I've always liked Akros a lot and respect him quite a lot too. I suppose I should've brought out some more expensive sets to compare against. I saw that you said you enjoy bass, but not the kind which will color the rest of the mix to a fault, basically. You want good, solid, tight bass from an iem which will take an already bassy track and not over emphasize that region. I get that. I can say this, the Hydro does have an emphasis in the mid-bass, a big one. However, while the sub-bass is lifted and deep, it isn't the type which gives too much weight to the mid-bass making it sound slow or too wide in its presence. If that makes sense. Bass notes have good contour to them and they aren't slow "per the quantity".
@Ceeluh7 thanks for the detailed explanation! Do you think this set is capable to compete with more expensive sets like say Yanyin Canon II or Aful Performer 8 from your reviews?


100+ Head-Fier
CCA Hydro Review: A Taste of The Top!
Pros: The most technical CCA/KZ IEM
Comes with a surprisingly premium cable (add $10)
Good coherency
Punchy but clean bass
Open, clean mids
Sparkly, well-detailed treble
Good technical ability
Tuning switches can drastically change your listening experience and fit your preferences (from basshead to somewhat diffused field)
Good scaling ability
Cons: Comfort (shell too big)
Slightly metallic-sounding timbre
Lacks bass tactility
Might be too bright for some

CCA Hydro Review: A Taste of The Top!​


PRICE: $120​


  • The most technical CCA/KZ IEM
  • Comes with a surprisingly premium cable (add $10)
  • Good coherency
  • Punchy but clean bass
  • Open, clean mids
  • Sparkly, well-detailed treble
  • Good technical ability
  • Tuning switches can drastically change your listening experience and fit your preferences (from basshead to somewhat diffused field)
  • Good scaling ability


  • Comfort (shell too big)
  • Slightly metallic-sounding timbre
  • Lacks bass tactility
  • Might be too bright for some


  • People who love the Rhapsody, Castor Bass and Trio
  • People who want the most technical sounding CCA/KZ
  • People who want a high driver count hybrid with good coherency
  • People who want a refined version of the Harman bass boost
  • People who want a fun yet detailed set


  • People who want natural timbre
  • People who want a very tactile sounding bass
  • People who want a smaller sized IEM
  • People who don’t like tuning switches
  • People who hate midbass tuck


  • Most genres (very versatile IEM overall)


CCA have their most refined and most technical IEM with the Hydro by far. The level of maturity while keeping the KZ’s fun and snappy sound is impressive and goes to show the work they did in this IEM. Very technical sounding with a refined version of their Harman Bass-Boost makes this a genuinely fun set. And while I do think that it struggles to stand out in the tough $100 market, it lives up to being CCA’s true flagship IEM. RECOMMENDED!


When David was pitted against Goliath, everyone thought that David had no chance. He was just a man after all and Goliath is a giant. But against all odds, David beat Goliath and proved everyone wrong. But what happens when David becomes Goliath? What happens when the giant slayer becomes the Giant? What happens when a company known for great value in-ear monitors comes out with a $130 flagship in-ear?

DISCLAIMER: The KZ Hydro was sent over by KZ in exchange for my honest impressions. I am eternally grateful for the opportunity. I was not paid. Rest assured, my thoughts and opinions on this product will be my own honest opinions and will not be affected by the facts beforehand.


KZ and CCA are often attributed to the best value in-ear monitors that you can buy in the market. They’ve been providing some of the best budget IEMs for years and non-audiophiles are probably aware of one or two of their IEMs.

What they’re not known for are flagship in-ear monitors. Particularly, anything more expensive than $100. Sure, there are sets that go beyond $100 like the AS24, but that’s the exception and not the rule. So when I found out that CCA is coming out with a $130 IEM, my interest was piqued and I wanted to know exactly what set this apart from the other CCA IEMs? Let’s find out!



The unboxing experience of the CCA Hydro is basically the same as other KZ/CCA sets. The difference is that this is closer to the unboxing of the CCA Rhapsody with a black box and a paper print of the details of the IEM. I guess we gotta save costs.

Here are the inclusions:
  • CCA Hydro IEMs
  • 784-core cable
  • KZ Starline Eartips
  • Tuning stick
  • Manual


To keep it short, the tips are fine and the inclusion of the manual and tuning stick is necessary


This is where the Hydro starts to justify its $130 price tag. Starting with the internals, the Hydro features 2 Dynamic Drivers and a whopping 8 Balanced Armature Drivers. The DDs are their patented XUN-7 and the balanced armatures are their 31736 that were found on the CCA Rhapsody a few months back.


Aesthetically, it fits the other CCA sets. Really nice-looking faceplate that is ruined by the typography. Please CCA, just go back to not putting stupid fonts on your IEMs. Do what you guys are doing with the ZSN or ZS10 where it’s clean and minimal.


Anyways, aesthetics aside, the fit is also quite reminiscent of the Rhapsody. Big, chunky, and hurts your ears after a few hours of wear. It’s to be expected considering this has SO many drivers packed into it, but still something to consider. Stability is VERY good and the seal is also fantastic. However, it unfortunately has air pressure build-up like the Rhapsody which means if you’re sensitive to feeling like your ears are being choked, then this will not be comfy. Otherwise, very stable and well-sealing set.


But arguably the most shocking aspect of the Hydro is the fact that it comes with a good cable. No seriously, I know I’ve expressed my satisfaction with the stock KZ/CCA cable but this is actually a different cable. This is a 8-strand 784 core beefy cable that feels quite premium and heavy.. This means adding $10 on top of the $120 price tag, making this a whopping $130 with the upgrade cable. But it’s worth it to distinguish this from the normal budget CCA set.


NOTE: As the Rhapsody has 5 official tuning modes, I will be describing the sound of the stock (ALL UP) configuration and compare the other tunings in their respective sections:

Sound Signature:​


The Hydro’s sound signature is the modern iteration of the KZ V, which is basically a Harman Bass-boost that they started with the Castor Bass Enhanced. This means big but tucked bass that minimizes bloat and midbass bleed, clean, open but somewhat recessed midrange and a forward, sparkly and snappy treble with good air extension. This is by far the more refined iteration of the sound signature and it should for $130, but still suffers slightly from a little bit of incoherency between the slower bass and snappier treble, but that’s to be expected from hybrid in-ears.


With an impedance of 15-20 ohms and sensitivity of 102dB, the Hydro’s are expectedly easy to drive. It’s harder to drive compared to their other, more budget-oriented sets which also allows the Hydro to be quite the scaler. On lower-powered sources, it sounds adequate and enjoyable. But throwing this into a more powerful and warmer source will give it the much-needed tactility and shift the treble to sound smoother and cleaner.


As a Harman bass-boost set, the Hydro presents bass in one of the cleanest yet most engaging ways that I’ve heard in any KZ IEM. It’s fast, it’s snappy but completely unintrusive to the midrange and still retains a solid sense of impact and punchiness. It’s not as big as the graph might make it look like and sounds more balanced with slight emphasis around the 80hz region over the 20hz region. This gives it more punch and less rumble which is both good and bad as too much subbass have the tendency to mask over the midbass when pushed too far. My problem lies with the overall tactility and the fact that it is tucked. The bass of the Hydro isn’t the most tactile bass in the sense that bass guitar riffs and kick drums may sound well-defined, but don’t have that extra oomph or texture on the attack of each note. The tuck is more of a personal preference, but the switches do actually shift the tuck quite a bit and this comment only applies to the UUUU, DDUU, and DDUU configurations. But in the stock configuration, it affects the body of the lower mids which I’ll be talking about later.

Listening to D’Anglo tracks, you get a very immersive sense of bass that goes quite deep but isn’t quite as textured. It’s smooth but to a respectable degree, nothing too problematic but I would’ve either preferred a deeper bass or a more tactile midbass.


To be expected from a Harman-bass boost set, the midbass tuck is quite evident with male vocals sounding quite thin and occasionally distant on certain tracks. It doesn’t sound as recessed compared to other IEMs that do the Harman tuck, but it’s definitely not the most bodied or natural-sounding male vocal presentation that I’ve heard. Female vocals fair MUCH better and sound absolutely lovely where they’re rendered with such energy and nuance that is often a highlight for KZ/CCA IEMs. The Hydro probably does this the best out of all the KZ/CCA IEMs that I’ve heard so far. This carries over to instruments with bass guitars still retaining a good body and note weight, but lacking tactility as mentioned earlier. Air instruments sound absolutely fantastic, particularly flutes and trumpets. I will say though that the transition from bass to lower mids doesn’t feel so drastic that I’d be able to tell where the bass ended and the lower mids started.

I found instrumental and orchestral tracks to really fit the Hydro’s midrange. Listening to Diving In by Vincent Diamante, the combination of the deep drums, the flutes, and the trumpets provide such a harmonious listening experience on the hydro that I was genuinely surprised by how nuanced the mids of the hydro were in the upper frequencies. The trumpets sang and the flutes followed beautifully in the climax starting at 00:30 where the ensemble comes into form. Such a beautiful listening experience!


The treble of the Hydro is surprisingly smooth despite being as bright as it is. It’s no EM6L smooth, but it’s damn smooth, especially for a CCA IEM. The level of refinement brought to the treble here is genuinely impressive as it sounds very energetic and lively while keeping it free from harshness or edginess. It might come across as a little too bright for some, don’t get me wrong. It’s no treble-sensitive sets, but that’s something you can expect from KZ/CCA IEMs. But this is the most refined that I’ve heard their treble sounded. My only gripe is that the metallic timbre here is quite noticeable, especially in the all-up configuration where they tuck the bass earlier which loses the midbass to contrast the treble. Nonetheless, it’s a very snappy yet refined-sounding treble.

Listening to Game of Love by Daft Punk, the cymbals sound absolutely lovely and compliments the basslines and synths very nicely. It’s definitely on the hotter side when you crank the volume to balance out the mids, but it sounds very satisfying hearing the splash of each hit.


This is, by far, the most technical-sounding CCA IEM that I’ve heard. Solid separation and layering ability, decently immersive staging and imaging, and crisp and pretty good transients and resolving ability. Probably the worst aspect about the Hydro is the dynamics as I find it sorely lacking, especially in the low frequencies. Bass nuances aren’t the most well-defined and don’t really provide that tactile sensation that I look for.


Casual Use​

Media consumption is fantastic on the Hydro. The combination of big bass and energetic treble makes watching movies absolutely fantastic here. It’s extremely immersive and I never feel like I miss out on anything. My problem is comfort. I cannot watch an entire movie without needing to take these off and give my ears a break. At the very least, these have great passive noise canceling that blocks off the majority of the sounds while commuting or in a noisy place and would be a great alternative to active noise canceling buds in my experience. It also has superb stability, so you won’t find these popping out of your ears while you walk

Gaming Use​

Like the Rhapsody, Castor, and Trio before, the tuning of the Hydro perfectly fits gaming mediums, both competitive and immersive. Competitive games want a lot of bass, but clean enough to not sound muddy. It also wants a shoutier set to bring out the upper-frequency details without being too harsh. The Hydro does that absolutely perfect and I genuinely loved using this for competitive gaming. Immersive gaming is also fantastic as playing games like Sky: The Children of Light (which is where the Vincent Diamante song came from) with the slow and relaxed moments followed by big set pieces are perfectly rendered on the Hydro. It’s a fantastic gaming set and I highly recommend it for that.


DDDD (0000)

  • This mode is basically the untucked version, a more v-shaped version of the KZ Harman bass boost. The bass is admittedly on the muddier side, but it smoothens the treble in turn. It takes a hit on overall cleanliness and separation ability as the bass tends to bleed into the midrange.

UDDD (1000)

  • This pushes the bass up very slightly from the all-DDDD configuration. Not that big of a change in my opinion, but it slowly starts being a basshead set

UUDD (1100)

  • Basically the basshead setting for the Hydro. VERY deep and engaging bass that is honestly perfect for hip-hop and other bass-heavy genres. If I was a basshead, this would be my favorite tuning. Otherwise, it’s quite muddy and bloated sounding.

DDUD (0010)

  • Closer to the UUUU configuration but takes the bass slightly down, similar to the UDDD configuration but in reverse. Not that big of a difference from the all-up

DDUU (00110)

  • The treblehead setting, aka almost my favorite setting. Due to the tuck in the lower mids, I didn’t enjoy this setting as much. The treble sounding a little bit metallic also made the midrange sound a little thin and stale. But this was the most sparkly and energetic tuning and fit the classical/instrumental/orchestral genres the best.

UUUD (1110)

  • Arguably the best setting that balances the bass energy from the DDDD setting with the energetic DDUU setting. Basically the most balanced setting out of all the tuning modes.


vs CCA Rhapsody​


In short, the direct upgrade to the Rhapsody. Better, more refined bass, cleaner mids, cleaner treble, better technicalities. The bass sounds a little deeper and more engaging on the Rhapsody, but is quite sloppy and lacks definition. The only thing they have in common is the balanced armatures as well as that ridiculously massive shell that also has air pressure build-up

vs CCA Trio​


Oddly, I actually find the CCA Trio to be better tuned than the Hydro. The bass is a little bit cleaner while having more body in the midbass and the mids generally don’t sound as recessed. However, the Hydro is considerably more technical and refined sound, especially in the treble region compared to the Trio.

vs KZ Castor Bass​


Basically the same comments as Rhapsody, but CONSIDERABLY more technical and more refined sounding. Oddly, the shell of the Castor Bass is more comfortable to wear than the Hydro

vs Celest Phoenixcall​


Two jam-packed sets in terms of driver count but varies in presentation. The Phoenixcall has a more bodied, richer, and more natural-sounding vocal presentation (odd I know) compared to the Hydro, but the Hydro is better extended on both ends with a snappier overall sound. Technicalities have to go to the Phoenixcall, particularly in how much cleaner the separation is on the Phoenixcall. The Phoenixcall also has less of a metallic tinge to the treble region compared to the Hydro.

vs Simgot EM6L​


The EM6L sounds considerably smoother than the Hydro, but both suffer from a lack of luster in bass texturing and a slightly metallic-sounding treble. Timbre is slightly better on the EM6L. Technicalities are similar on the EM6L, but with slightly cleaner separation on the EM6L

vs Simgot EA500LM​


The EA500LM sounds considerably more natural than the Hydro despite being quite bright on its own. Dynamics are also considerably better on the EA500LM and the overall coherency is better. The EA500LM sounds more technical than the Hydro overall but maintains a similar resolving ability with the Hydro.


In a vacuum, the Hydro is a fantastic IEM. Very engaging and punchy bass, open and clean sounding mids, sparkly and detailed treble, and a respectable level of technicalities. In fact, I’d even go as to claim that the Hydro IS the best CCA/KZ IEM that follows their modern tuning standards TO DATE. If you liked their previous Harman Bass-Boost set, I can guarantee that the Hydro is the best of the best with that kind of tuning. The fun yet clean overall sound makes it such a good performer in the entirity of KZ/CCA’s catalogue.

Unfortunately, it landed itself in a very awkward price range. You have sets like the Celest Phoenixcall being all weird but quite technical and the Simgot EM6L and EA500LM redefining how good IEMs could be around the $100 price range. Even for its barebones price of $120, I struggle to find anything that makes the Hydro stand out. And that’s my biggest gripe about it. Not that it’s a bad IEM, far from it. But CCA played it so safe with the Hydro, pairing their “flagship” IEM with accessories that literally come with their $5 IEMs, barring that cable. KZ/CCA has always been known for great value, and the Hydro, despite its very refined tuning and technical ability, lands itself in a very safe spot that doesn’t make it stand out in any way compared to other non-KZ/CCA sets. For $130, you start expecting more than just a well-tuned and technical-sounding IEM. If it’s not the listening experience being unique, it’s the package that it comes with. And that’s where I believe the Hydro falls short.

Regardless, I have to give CCA the props for creating basically their ultimate Harman Bass-Boost IEM. The most refined, cleanest, and most technical CCA IEM that I’ve heard by far. This outcompetes every single KZ/CCA IEM that has been released that follows this kind of tuning and if they keep this up and slowly trim the price, CCA might just have something that can spark a budget revolution like they did years ago. And I think that’s worth mentioning as it really lives up to its flagship nature in that sense.

Thank you for reading my review of the CCA Hydro. If you would like to order one, consider using the non-affiliated link below:
In your basshead settings 1100 and 1110 how do you feel the tuning scales with volume? Is there more emphasis on the treble and gets slightly too much then or does it stay controlled?