Cayin YB04

General Information

  • Knowles/Sonion BA Combination
  • CNC Aluminum Enclosure
  • 8-wire Unidirectional Crystalized OFC x Silver Alloy cable
  • High Quality 3.5mm Gold Plated Connector
  • Hexagon Design Aluminum Spliiter
  • Gold-plated 0.78mm 2-pin Connectors



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Pros: Impeccable build
- Resolving treble
- Good micro-detail retrieval
- Not too picky with sources/very easy to drive
Cons: Stock cable has annoying memory hooks
- Heavy housings
- Bass extension is lacking
- Upper-Midrange can get shouty/harsh on high volume
Cayin YB04 Review
Opening Shot


Judging the “first ever” product in a brand’s lineup is quite perplexing.

There’s no precedence, so it has nothing to live up to (in a sense). Mostly there isn’t much expectation; it’s new, so you just don’t know what might come out of it. On the flip-side, if it’s a turd — that’s the end of said product line for the most part, and the company has to either bury the very existence of it (Amazon Fire Phone, anyone?) or just deal with the stigma forever (Microsoft Kin, darn).

Cayin’s first ever IEM, the YB04, faces that particular dilemma. If it’s too safe/bland in terms of tuning, it might not stand out and be forgotten over time; or if it’s too unique, there might not be a successor at all.
Note: the ratings given will be subjective to the price tier. Definitely the expectations from a $15 IEM won’t be the same as a $150 one, and that’s the approach taken while assigning scores. Cayin was kind enough to send me the YB04 (courtesy of Andy Kong) as part of the review tour.
Sources used: Questyle QP1R, LG G7, Cayin N6 II, E1DA PowerDAC V2
Price, while reviewed: $400.

Having already reviewed the TOTL Cayin N6 II DAP, it’s time to check out how well they’ve nailed the IEM tuning test at the opening shot. Bullseye, or bust?


Build: Cayin usually gets the build quality right, and they’ve hit it out of the park again. These IEMs are incredibly well built, as good as anything out there. I’m glad that they chose an Aluminium alloy instead of the usual boring Resin shells as it just feels more premium in hand.

The IEMs have somewhat of an oblong pentagonal shape, which is rather striking when viewed in person. The backplate is removable (it uses the same Torx T5 screws as Cayin’s N6II players) and it seems like a great option to either DIY the shell with spray-paints/custom prints, or just make repairing the IEMs easier if such need ever arises. The raised geometric patterns on the backplate also give an industrial vibe to the overall design language.

Opening up the backplate you can see the internal wiring and the (plastic) driver chamber, along with the crossover circuitry. The driver chamber also consists of the wave-guides (to help with the cross-over issues such that phase incoherence etc.).
I couldn’t find any visible vent-hole in the IEM, though that’s likely not needed due to these using a BA-only schema (and the Sonion Woofers are not of the vented type). Naturally that leads to high noise isolation, provided you can get a good seal.

Then on the sides you can see the Cayin logo tastefully etched on the upper portion, while at the bottom there is the 2-pin connector (Cayin supplies a QDC-type connector here). The channel markings are right beside the nozzle along with color-coded dots beside the 2-pin connector. The nozzle has a steel mesh acting as wax-guard.

To summarize: impeccable build and finish, and wouldn’t feel out of place in a kilobuck IEM.


Accessories: Before getting into the accessories, I should probably talk about the box it comes in first. Man, Cayin knows how to make elaborate packaging. It’s great to look at and you feel like you’ve definitely bought something worth the price-tag. The IEMs are very well-protected with more than enough padding to likely survive a 10-story fall. Don’t test that claim, please.

Inside, you get the IEMs themselves nicely laid out with the wire already connected (I couldn’t take a shot of that since my review unit had the wires separated). Then there are the 12 pairs of eartips, 9 pairs of them sorted as Vocal, Balanced and Bass eartips (3 pairs each), a pair of dual-flange tips, and 2 pairs of foam tips. Unfortunately the stem of the Balanced tips (sonically best of them, to my tastes) were too stiff and caused pain in my inner-ears, so I decided to switch to Spinfit CP-500 which provided a similar sound without the comfort issues. Your mileage, of course, may vary.

Then you get the most exuberant leather case you will likely see in a while. It’s large, impractical if not impossible to carry in pant pockets and has a magnetic clasp. Yet, I adore it. I do wish the padding inside was softer. It should also have a cleaning cloth, a shirt-clip and a cleaning tool inside.

Finally, about the cable. This might be a contentious point but I’ll be frank — this cable is subpar in its build quality and overall usability. First, the good stuff — it’s lightweight, supple, the Y-split and 3.5mm connector jacks look awesome with their geometric shapes and subtle branding, and it’s not microphonic. This is where the good stuff ends though. That memory wire, for one, is beyond annoying. It’s stiff and unless you outright remove it with a knife — it’s there to make your life difficult. Then comes the strain reliefs. The Y-split only has a bottom strain-relief (you also need one at the top for obvious reasons) while the relief on the 3.5mm jack is too stiff to be of any use. As a result, you may find that the braiding of the wire around the jack has come loose.

So yes, while the case is great, it’s not too practical to carry around. The eartip selection is good, but the stem is very stiff on the preferred Balanced tips. The cable looks good upon first glance, then you try to wear the IEMs battling the memory wires. The fancy points are scored at the expense of usability and practicality, and that’s a bummer.


Comfort: The YB-04 is heavy, and has a short-ish nozzle that’s also quite thick. The end result is obviously something less than ideal. It’s not an IEM you put on and then forget about. The stock cable with it’s horrible memory wires don’t help as well, so I often had to take a break every 30 mins or so. Swapping to a better cable helped, but didn’t make them as comfortable as, say, Meze Rai Penta. I also found out that they are not suitable for listening while lying down as the weight tends to loosen up the seal.

Now, onto the sound. This is a quad-Balanced Armature setup, with dual Sonion woofers (33AJ007i sealed variant most likely) and dual Knowles SWFK-31736 as the mid-to-high drivers. The crossover setup is a two-way crossover. The sound impressions below were mostly formed with the CP-500 or stock Balanced tips, and Cayin N6ii as the source (since Cayin advertises them to mesh well).

Lows: Cayin aims for a balanced low-end presentation with these, which obviously means a total lack of sub-bass rumble and a mid-bass that’s mostly there for immediate impact rather than substantial body/slam/whatever you may want to call it. Snare hits lack body, and if you’re a drum track aficionado this might not be the most ideal pair for you.

On the plus side, there’s no mid-bass bleed into the lower mids, so — hurrah? Moreover, the bass speed is fast with the typical unnaturally fast bass decay, which if you prefer the nimbleness of BA bass will be right up your alley.

Overall, there is not much to see here for those who prefer south of neutral bass, let alone the bass-heads. It’s a conscious tuning decision and as such might be the deal breaker/maker for you depending on your preferences.

Mid-range is in the front and center of the YB04’s tuning philosophy, and as such should be the most critically judged aspect of the signature. First up, the overall frequency response. The rise from the lower mids to the upper mids is smooth and very well executed. Thanks to the flat-ish bass response, mid-range doesn’t suffer from any bass-bleed, so you don’t suffer lower-mids congestion. However, due to the emphasis on the upper-mids, lower mids take a back seat for the most part and thus deep/baritone vocals sound distant, lacking the heft they should display.

Then comes the upper-mid tuning, and here I encounter some oddities. First up, it’s very apparent that Cayin is going in their own tuning direction rather than conforming to Harman 2019 or the DF target. Thus instead of the usual 3KHz pinna gain, we are met with a “sawtooth” upper-mid and lower-treble peak trio: one at 2KHz, one at 4KHz, and to wrap it up: one that 6KHz. The (un)holy trio if you are upper-mid and lower-treble sensitive.

Thankfully, it’s not so intense for the most part. While the ~8dB of extra boost in the upper mids and lower-treble regions might seem scary, they don’t sound as exaggerated in most tracks. This contrast between the upper and lower frequencies also aids somewhat in instrument separation with higher pitched vocals and string instruments being placed at the forefront.

Vocals have good texture, though the singers breathing in/out aren’t as natural as on certain other IEMs. String instruments sound especially sharp and will be right up your alley if you prefer a brighter string representation. Overall timbre is mostly natural though the upper-mids and lower-mids tend to be brighter in nature. Overall detail retrieval is excellent for the price-range and unless you are used to TOTL level of resolution — this should serve you really well.

All that being said, I’ve still encountered some harshness in upper-mids at high volumes, while certain tracks have a tendency to get sibilant (Lifehouse’s Somewhere in Between), or walk a fine line. It mostly happens in poorly mastered record, but certain well-recorded tracks also exhibit this. The YB04 can also be a bit intense if you are sensitive to 4-6KHz peaks so do keep that in mind.

This is the most favorite part of the YB04 for me. Cayin has tuned the treble masterfully and I can’t really find anything wrong with it. Cymbals crash with authority when needed, and then goes behind in the mix if the track is mastered as such. Violins sound smooth and the transition from one higher note to another is seamless. I do wish they put a bit more emphasis on the 8KHz, perhaps a linear fall instead of an abrupt dip, as it would’ve made cymbals strikes more prominent on certain metal tracks. But even in stock tuning I immensely enjoyed the cymbal strikes on Breaking Benjamin’s The Diary of Jane.

I do miss the shimmer and air that you get from some upper-tier IEMs with even better treble extension (e.g. Campfire Andromeda). Cayin has a small post-10KHz peak but then it rolls. At this point though, it’s basically nitpicking, and since the treble here can convey most of the details without messing with the FR too much — I am rather pleased.


Note: the following two sections may have varying perceptions for each individual due to a number of factors e.g. pyschoacoustics, insertion depth, ambient noise etc.

Soundstage: Soundstage width isn’t the best even when compared to some lower-tier IEMs, but the soundstage depth is really good. Loreena McKennitt’s Live rendition of Dante’s Prayer has an applaud section around the end of the performance, and it sounds plenty realistic on the YB04.

Imaging is fairly well-done, though I couldn’t quite get the 3D-holographic imaging I get on, say, the R2 Atens. The cardinal imaging (top/bottom left/right) were tad hazier and thus this didn’t seem to have the most accurate instrument placement.

Before I go on with this section, I should mention that for me ~$500 is the cut-off point for this bang-for-buck section. Anything more expensive will definitely sit on the diminishing returns spectrum. Since the YB04 is priced at $400, I will pit it against some higher-end stuff in the comparison section. I’ll just summarize it here: it can keep up pretty well in terms of mid-range resolution and vocal rendition even when pitted against higher tier stuff. Where it falls short: bass, treble extension, and soundstage/imaging. However, I’m still not amused with that cable and the stock tips so I need to consider people having to replace them.


Source and Amping: While the YB04 doesn’t need much power to run (most dongles and phones will get you to sufficient volume), it will pair better with slightly warm sounding source rather than the analytical ones. My LG G7 for example made the mid-range more shouty, while the QP1R and Cayin’s own N6ii tamed that into a more enjoyable presentation. A low output impedance is mandatory as well due to its BA-only design (higher output impedance sources will skew the frequency response).

Select Comparisons

Fiio FH7: The Fiio FH7 is, for now, the flagship of Fiio’s IEM lineup and has garnered quite a following. It is a five-driver hybrid, with 4 BA drivers taking care of the mids and highs while a large 13.6mm Beryllium coated dynamic driver is tasked with low-end/bass duties. Being priced similar to the YB04 at $450, this will make for a very interesting comparison indeed.
Both IEMs are incredibly well built, and both come with plethora of accessories though I’m more partial to the Fiio accessories pack due to the inclusion of Spinfit tips along with switchable filters and a soft carry pouch. FH7 is also more comfortable thanks to a more ergonomic nozzle design and angle.
In terms of sound quality, the FH7 pulls ahead when the low-end kicks in. That dynamic driver is too hot to handle for the mere BA woofers on the YB04. However, YB04 immediately delivers a counter-attack with the midrange rendition that’s more upfront and less recessed than the FH7. Cayin also delivers better timbre to the midrange instruments, though both fall short of perfection. Treble is also more accentuated on the YB04 and can exhibit more apparent micro-detail retrieval, albeit this can be a bit too much for long-listening sessions. FH7 is less fatiguing in comparison but pushing the volume high can make the treble harsh and exhibit some grain. YB04 also has more upper-treble extension. Soundstage is similar while imaging is slightly better on the FH7.
As it stands, the bass response is what you need to consider if your choice is between these two. The midrange and treble differences are less stark, while comfort is indeed FH7’s forte.

vs Meze Rai Penta: The Rai Penta is Meze’s 5BA TOTL offering, and costs more than twice of the YB04 at ~$1000.
Rai Penta is definitely a looker, and the fit/finish is even better than the YB04. The shell is smoother with a more ergonomic shape and you can wear them for hours without the slightest bit of discomfort. The accessories are also of higher quality but given the price differential it’s expected.
When it comes to sound, they are polar opposite signatures. The Rai Penta is a mellow, laid-back listen while the YB04 focuses on detail retrieval across the board. Mid-bass is more boosted on the Rai Penta, and it’s followed by a midrange that’s mostly similar up until the upper mids where YB04 boosts 4K region further, and Meze takes a down-turn and mostly plays it safe along the rest of the frequencies. The tonality of the Rai Penta is more natural with less shout in the upper-mids, but the lack of treble energy can cause lack of dynamism in many heavier genres. Soundstage is wider on the YB04 while imaging is about similar.
Despite being priced half as much as the Rai Penta, the YB04 definitely comes ahead in terms of technicalities. These two IEMs are aimed at different audiences/genre however and they complement each other rather than compete.



Cayin has got a lot right with their first attempt at an IEM. It’s impeccably built, the price-tag is mostly competitive and they do somewhat achieve their target of an energetic, detailed signature.

The biggest room for improvement is in the bass department, as right now it’s lacking both impact and extension. Another potential improvement can be done in the mid-range to make it less peaky and have a smoother low-to-upper-mids transition. Treble response is mostly fine and apart from slight reduction in the 6KHz region and have a bit more upper-treble boost, there isn’t much I can complain about.

The shell isn’t ergonomic however and might be the biggest point of contention for potential users. The eartips and cable need some work as well. Availability is another issue as I couldn’t find them on Amazon whereas Fiio FH7 is there for a while. If Cayin can address these issues with the next iteration, we may as well have a default recommendation in the $500 range.

To summarize, the YB04 is a good option if you want something mid-centric that will retrieve gobs of detail without fatiguing you constantly.

Test tracks (as Tidal playlist):
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Pros: Incredible build, comfort and styling. Soft and very relaxing sound. Beautiful cable and prideful unboxing experience. Surplus of tips available.
Cons: Doesn't have bass slam nor treble "shine" that many may want.
*To me at least, the format isn't showing my full review (even the HIGHLY shortened and edited one I had to post here thanks to Head-Fi's new 10k character limit). I have posted my full, unedited, review on the Cayin YB-04 forum page here.*

*Yes, I'm sure you've noticed but I used the wrong form of through in my video cover. Didn't even realize I did it until obviously too late. Oh well. We'll have a laugh at it together.*
The Opening Experience


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Pros: Natural, non-fatiguing sound. Excellent build quality. Good fit. Amazing IEM case.
Cons: Bass light for my tastes. Cable could be better (being picky).
Disclaimer: As part of the Cayin N6II and YB04 tour I was lent these IEMs to try in exchange for an honest review. I am in no way associated with Cayin.

The YB04 is Cayin's first IEM and is positioned as a mid-priced multi BA over ear unit with a premium metal build and engaging, powerful, natural sound. The market <£1000 is pretty crowded, especially with all the new gems coming from China so lets see how the YB04 performs (in my honest opinion of course)...

The YB-04 specification is as follows;

  • Driver units: 4 balanced armature drivers; Tweeter: Knowles x 2; Woofer: Sonion x 2
  • Frequency response: 18Hz ~ 40kHz
  • Impedance: 30
  • Sensitivity: 113dB @1kHz +/-2dB
  • Enclosure: Machined CNC Aviation Aluminium Alloy
  • Headphone Cable: Unidirectional crystalized OFC, Silver Alloy
  • Input connector: 0.35mm TRS Singled-ended
  • Earphone connector: 2-pin 0.78mm
  • Price: currently £449

In The box:

In the (quite large) box you get:

  • YB04 IEM
  • 8 wire Copper/Silver alloy cable, 2pin 0.78mm
  • 12 pairs of ear tips (2 flange, bass, balanced )
  • The fantastic Tan leather case (plenty of space for the IEM + cable + tips). I would buy this case alone for my current earphones.
  • Cable clip
  • Cleaning brush and cloth
  • User manual
Unboxing is a nice experience, getting to the IEM is easy and all contents well protected. The box is actually quite large for what's in it - good protection I guess.

I really like the selection of tips, but after top rolling found the medium balanced to be my favourites.

I love the Tan leather case which has lots of space of the IEM, cable, tips, cleaning brush etc. and protects everything inside. It looks great, feels great and I could get 2x IEM in the same box (Fearless S8f & YB04). I wish more manufacturers would provide this level of accessory as I mostly use earphones on the move and need a secure case.

YB04 Case

Build Quality & Design:

Much like the N6ii, the YB04's build quality is excellent. Machined aluminium shells with screw on faceplates feel solid in the hand and look great. I particularly like the red and blue dots donating Left and Right orientations, useful when both shells look identical (the cable has identical markings too). The nozzle has a mesh wax guard and a very pronounced flange helping tips to stay in place.

Cable connection is via the standard 2pin 0.78mm socket so you can use aftermarket cables. Remember the actual socket raises out of the shell so the best connector would make use of a recessed 2pin plug such that the plug housing slips over the raised socket - just like the supplied cable does. This gives a very secure connection for all those times you pull and push at the cable connection (in/out of bags, dropping your DAP etc.).

YB04 cable detached

YB04 faceplate

The YB04 + Cable (had my own random tips on there for the pics)

I am not one to really care too much about cable 'sound'. To me the only thing that changes is the impedance. But cables make a difference in terms of practicality and looks. The included cable is totally fine. Looks nice, seems strong and well made. Very few microphonics when walking with the YB04 and well shaped over ear bend (although I would have liked to see some memory wire in this section so I could mould the cable a little more). The plug is a 3.5mm straight metal type with a long neck allowing insertion past thick DAP/Phone cases. Cable stain relief is OK, nothing special. Y split is a metal unit with a hexagon shape and a rubber slider to tighten the cables up. Cable length is 1.3m, not too long but still allows me to hold my DAP in front of my stomach whilst routing the cable through my shirt.


The shells are of a medium size, quite similar to my Freedom S8f (maybe a little larger) and fit in my medium ears just fine with no pain or pressure points. I should state here that I was using medium silicone ear tips which suggests the metal YB04 nozzle diameter is an ideal size for me. Isolation with universals really comes down to nozzle width/depth and tip size. I found medium tips work best and provide decent isolation - can gently hear peoples conversations at normal voice level without any music playing.

Surprisingly the shell didn't feel at all cold to my ear even though it's metal on skin, which is nice as I often have earphones dangling around whilst outside in the cold e.g. queuing to board a plane, riding outside in winter etc. The cable bend feeds easily over the ear and can be slightly moulded in place. I did find the over ear bend would loosen up a bit after some time and I had to re-adjust (some memory wire would sort that out).

The shell fits fairly flush with my ear and I can lay my head on a pillow without much discomfort.

My wife has small ears and tried the fit with medium tips. Again, the fit was just fine and she obtained a good seal without any discomfort. I'd say the shell size is spot-on unless you have very small ears.


TL:DR: Lovely precise natural tuning, with fast attack and natural note decay. Great sound stage, kinda puts you a few rows back from the stage. Excellent stereo imaging and not at all fatiguing. Probably not for bass-heads.

I tested the sound using the Cayin N6ii with my preferred EQ setting using the same music files, stock cable and medium balanced tips.

Before we get into it, the included tips pretty much do what they say on the tin - bass tips = more bass, balanced = more balanced, vocal = more high-mid/high end, bi-flange = better isolation. After listening to them all, I found the medium balanced tips to be my favourite. I would have bet a lot of money that I would have proffered the bass tips before testing, but 'balanced' and natural seems to be the tuning for these IEMs and using the bass/vocal tips seem to make the sound a little artificial and break away from the IEM inherent tuning. Bi-flange is OK and sounds a little more bass heavy, but I have never liked the way bi or triple flange tips feel.

Tracks I used are as follows:

  1. AC/DC - Sin City (FLAC)
  2. Black Sabbath - Children of the Sea (FLAC)
  3. Portishead - Numb (FLAC)
  4. Infected Mushroom - Heavy Weight (FLAC)
  5. Nirvana - Where did you sleep last night (FLAC)
Music impressions:

  1. AC/DC - Sin City (FLAC) - Symbols at the start of this track sound great and pronounced alongside solid midrange guitar rhythm and not overpowered by the bassline. The bassline itself is there but not overly extended. It seems the more mid-centric tuning gives this track a natural flavour, but I would like that bassline to shine. Bon's vocals are front and centre here and appear layered right on top of the instruments. At no point does this track sound congested - which I have found happens when bass bleeds into the lower mids.
  2. Black Sabbath - Children of the Sea (FLAC) - Tony's beautiful guitar sounds airy and natural, almost like he's sitting next to me. Again, the bassline is there but does not power through like I have heard. Dio sounds wonderful even when he goes deep. Bill's drum rolls sound great and move L to R well (thanks to the stereo imaging) and the fast attack really brings them to life.
  3. Portishead - Numb (FLAC) - As a glorious bass track, I could have done with some more low end. Even then it still sounds very musical (musical and fun is my general taste) and Beth's vocals come flying through the ensemble. Those light symbol strikes also shine.
  4. Infected Mushroom - Heavy Weight (FLAC) - This is a very holographic track (loads of sweeping sounds L and R) where the sounds seem to come from all around. That aspect is very nicely presented by the YB04. Top end sparkle all there and but bass is a bit light, which does not benefit the track. I'm a big drum freak and at 04:34 the drum beat sounds fast and musical. Vocals and guitars both sound natural and are right up front when they come in.
  5. Nirvana - Where did you sleep last night (Live, FLAC) - NOW YOU'RE TALKING! Man, Kurt really did an exceptional job didn't he! and it's all good on the YB04. I listened to this track over and over, even without the deeper bass notes I can close my eyes and I'm in the studio with them. This track brings out the best in the YB04 and I wonder if they didn't listen to it when tuning :)

Bass: Bass is there but won't slam your brain - but certainly not 'thin' sounding. Saying that its very detailed probably thanks to the speed of the YB04.
Mid: Fantastic note weight and fast guitars are not lost or congested. Male and female vocals are equally great.
High: A combination of fast attack, natural decay and great imaging produce wonderful musical sound that moves around your head. Extension is all there and does not seem to roll off at all, giving a very airy quality.
Sound stage: Right in the middle of the stage, a few rows back.
Other: The natural mid-centric tuning (to my ears) shines for acoustic music and the YB04's speed definitely works on rock tracks, preventing them from becoming loose or congested.

I did listen to this with my Cowon PM2 which adds some bass but the result is quite similar to the above comments. Cayin achieved great synergy with the N6ii ad YB04, but that's not surprising.


The YB04 is probably No.1 from all the (what I consider) mid-centric IEM's I've listened to, from Empire Ears to 64 Audio to JH Audio. Cayin really has the tuning spot on if you love acoustic/classical/rock music or want a very non-fatiguing, natural sound. At this price range there is a lot of competition but the YB04 shines through when you look at sound, build quality and ergonomics. If you're looking for a natural sounding, non-fatiguing IEM with excellent build quality and top accessories, definitely listen to the YB04.
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