1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.

    Dismiss Notice
  1. davidmolliere
    Black belt!
    Written by davidmolliere
    Published Oct 23, 2019
    Pros - Reference yet very musical and engaging tuning, not analytical with seamless crossover
    Outstanding clarity and transparency while remaining non fatiguing
    Remarkable pitch black background, highly distinctive and key to the overall signature
    Very wide and coherent soundstage with precise imaging
    Timbre are spot on
    Note attack and decay is very natural
    Superb fit for a universal IEM
    Cons - None that I can think of as long as you like a reference signature
    The YB04 provided for the review Tour is a loan sample and has to be returned. No incentive was given for a favorable review. This review is my honest opinion of the YB04.

    Listening notes
    I spent approximately 50 hours with the YB04, listening to Cayin N6ii (A01 and T01 motherboard ) with Dunu Hulk cable using balanced 4.4 plug. I also listened out of the AAW Capri cable (with 24/96 DAC and mini balanced amp) plugged into the iPhone.

    Special thanks
    Thanks to Andy Kong for organizing the Tour and allowing me to be part of it.


    The Cayin YB04 packaging is quite premium for a mid tier product, with a beautiful carrying case and a premium cable.



    • FR: 18Hz-40kHz
    • Impedance: 30 Ohm
    • Sensitivity: 113dB@1kHz
    • Enclosure: Machined CNC Aviation Aluminum Alloy
    • 2-pin and Single-ended (gold plated) 3.5mm termination, Unidirectional Crystalized OFC (30 core wire), Silver alloy (30 core wire) in the 8-wire cable

    Fit, Build & Isolation
    The YB04 build is flawless and the fit is superb for a universal. It looks sturdy, although I don’t know if the anodized paint is subject to scratch (I wouldn’t test this obviously). Isolation is good for a universal but as usual with aluminium, noisy environnement and lower listening level with let some exterior sound pass.


    Cayin doesn’t really need to be introduced as it’s a brand that has built a great reputation in audio for over 20 years, venturing in personal audio only later in 2013. Lately, they’ve been on a roll with a stuning flagship DAP in the N8 (the first featuring Korg Nutubes) and the N6ii (a modular DAP with switchable DAC/amp). Continuing the recent trend, the YB04 is their first IEM.

    On paper, a 4 BA IEM is rather uneventful in an era of trybrids and high count BA IEM. Still, when I had the opportunity to participate in a N6ii/T-01/YB04 Tour I couldn’t resist. Also, my experience is that tuning and implementation is just as important as any technical characteristics.

    On the YB04 product page Cayin claim « Outstanding clarity and musicality across the frequency band » and states « We don’t emphasis or enhance, we only reproduce the original. We don’t offer appealing resolution, we just put you there in person ».

    A very ambitious goal, let’s see if it holds its promises!


    The very first minutes listening to the YB04 were sufficient to see that the tuning intent of clarity and musicality has been very elegantly achieved. It’s a very open sounding unit with a wide and tall soundstage, depth being only average.

    The YB04 is all about balance between very strong technical foundations and a focus on musicality that doesn’t compromise its neutrality. This is harder to do than it appears and that’s why many IEMs that gave a shot at reference quickly ended up categorized as « boring », « dry » or « sterile ». The YB04 is anything but, as I found it highly engaging and lifelike in its presentation. We’ll dig deeper into this but I believe a lot of it has to do with a pitch black background.


    The YB04 bass reflects its reference tuning : sub bass extension is fair but if you’re looking or physicality you’ll definitely be disappointed. The mid bass presence is just as balanced, it does convey rhythm but lacks punch and weight. On the flip side you’ll get a fast, controlled and detailed presentation that conveys a lot of nuance.

    This is a general observation and since the YB04 is transparent to the source it can gain a bit of weight down low but don’t expect any kind of physicality. The YB04 will shine more on the subtleties of the double bass lower notes than the punch of percussive instruments. For this reason also you won’t get much coloration from the bass.

    The YB04 mids are seamless in the sense that separation is very good but the soundstage layout is not spaced in a unnatural way, it’s very coherent and natural against a pitch black background. This and accurate tone and timbre plays a great part in making the YB04 mids quite lifelike and engaging.

    Notes pop vividly against a black background, contributing to a very precise imaging, which is usually achieved with more separation and spread in the image layout. You get both a high degree of cohesiveness and separation, which is quite a challenge in my book.

    Lower mids have just enough presence and warmth to grant the YB04 a natural tone, but it’s very contained and some might find male vocals lacking a bit of power. The YB04 is not thin but it’s not thick either and the mids have a featherlike touch more than a voluptuous body.

    Overall vocal placement is slightly forward making for a clear vocal presence, and while I usually like my vocals with a touch of sweetness and warmth I found the crystal clear vocals were a treat on the YB04.

    Upper mids are nicely executed, not too much emphasis and I had a hard time finding any hint of sibilance or harshness : the YB04 is a fatigue free IEM which given its clear and transparent signature was not a given on every recording. You can find yourself to the edge sometimes but it’s staying on the free side of the edge for me.

    The YB04 treble is a good example of treble done right in my book, and a good indicator of the overall maturity that is found across the whole tuning. The product page says « We don’t offer appealing resolution, we just put you there in person ». The only thing I disagree with there is that the YB04 resolution is very appealing - just done in a way that isn’t relying artificially on boosted treble.

    Again, the black background is key to make this happen : think about it this way, you won’t need to push the volume in a totally quiet room. For the same reason Cayin didn’t have to push the treble, against a black background the treble notes contrasts greatly and shine without over emphasis. I think Cayin has done a great job of infusing enough energy in the lower treble section to make the YB04 exciting, but it’s a subtle and savvy tuning that can send shiver down your spine when called for while never becoming fatiguing.

    The upper treble section is seamless in the signature, it’s not the « in your face » technical upper treble presentation but rather the strong performer that shows restraint and stays within the goal of « We don’t emphasis or enhance, we only reproduce the original ».


    As I mentionner earlier, I came into this review Tour not really expecting anything extraordinary with the YB04. I was curious how Cayin, a mature audio brand, would address their first IEM. There already was a hint with the product’s positioning, firmly in the mid tier price wise, but the hint was not a clue at what the YB04 can bring to the table.

    You gathered it, I think the YB04 punches well above its price point and with some very distinctive qualities that sets it apart from the competition. It was a smart move to design an IEM with such an exceptionally black background (Black belt background ;P) that it doesn’t need to compete on the same basis as its competitors.

    Cayin showed across the whole tuning it remained true to the product’s intent, a sign of maturity that is quite impressive for a first IEM. Some manufacturers would have come out and make a statement with a pure performance or an eager to please signature. With the YB04 Cayin chose to be the best at what it aimed to do : reproducing the original, put you there in person and for this, they chose to remove any distraction from the background, keep the goal of a reference yet engaging sound, and in its own understated way show masterful restraint that makes it such an elegant sounding IEM.

    Quite a feat in my opinion, especially if you consider my own preference generally do lie in a thicker, warmer and more forward presentation. On top of this, my last review was such a special one as the FIBAE7 rocked me like nothing before it and the amount of time I spent with them before this review made me aware it would be a tough thing to review something afterwards. Call me impressed that the YB04 pulled me from my love affair and were able to shake me away from the F7 for a long bit! I am eager to see what kind of IEM range Cayin is going to build in the future… if this is mid tier, what would be a Cayin flagship IEM? I already have a big smile at the prospect!

    If you’re looking for a natural sounding and engaging reference IEM, with an exceptionnally black background that allows its distinctively elegant tuning to shine, you’d be hard pressed to find a better candidate especially at this price point! If you’re looking for a reference tuning with stronger bass foundations, the pricier Penta might be a better candidate.


    1. E0B5D6EF-C002-490F-9C4F-F80972CF0820.jpeg
    2. 80C2821F-9920-4360-9C60-D55B79F3AAD0.jpeg
      nappoler, josesol07, Dsnuts and 2 others like this.
    1. jeffhawke
      Nice review. It would have been useful however to have a few comparisons, the passing comment about the Fibae 7 makes one just wonder...
      jeffhawke, Oct 23, 2019
    2. davidmolliere
      Fair point. I’ll post comparisons later, just like source matching and cables... main comparison is to the Penta, the FIBAE7 are radically different tuning and on top of this a custom IEM.
      davidmolliere, Oct 23, 2019
  2. twiceboss
    Musical Reference Tuning
    Written by twiceboss
    Published Nov 3, 2019
    Pros - -Reference tuning with a touch of warmth in the mids
    -SQ punches above its price
    -Highs are well extended without being harsh
    Cons - -Not enough bass for basshead but again this is a reference tuning IEM
    Before I start my review, thanks to AndyKong for sending me YB04 with N6ii for a review!

    Build and comfort: These are outstanding! Metal build I believe. This set is really comfortable and it comes with many tips; balance, vocal, bass, double flange, and foam.

    Sound signature: Interesting tuning. This is almost like etymotic reference tuning. I will give two different sources here; apple dongle and n6ii pairing

    1. Apple dongle: The bass is lean. The mids is smooth and lush. Highs are well extended and really musical.

    2. N6ii 3.5mm T01: Straight up very musical. N6ii is indeed a musical dap that has a touch of warmth by giving bigger note weight. I certainly believe that there is a slight bump on 150Hz-250Hz for the warmth. With this warmth, there is like a perfect weight on vocals. Very crystal clear and musical mids. The bass is still in the leaner side but this time it is just better. More weight. For the highs; again, this is very well extended and very musical. Really musical pairing. I have an eq preset for Spotify Apple to mimic the N6ii, it’s not 1:1 same but you will get an idea at least! (Spotify EQ below for you to try)

    Spoiler: To me personally, I happen to like 3.5mm on N6ii rather than its balance. The single ended seems more airy and open. Very wide soundstage than the 4.4 out. Weird. 4.4output happens to slam better but it has significantly narrow soundstage. Choose which you like the most.


    Sonic presentation

    Bass: The subbass is not really well extended but the mid and upper bass are well executed to give weight for vocals. This is not for dance/EDM type of song if you are into it.

    Mids: With N6ii pairing, this set is AMAZING. Crystal clear and very lush mids. Separation of the mids is really pleasant and beautiful. Without the n6ii, just take this as less musical but the crystal clear retains.

    Vocals: Both male and female vocals are excellent. It is almost like this set is designed for vocals. Lush and clear vocals with perfect weight. Regarding the tonality, by having n6ii, the tonality is excellent. Without n6ii, you need to increase the note weight a little bit in eq.

    Highs: Very well extended! To me personally, this is a better set of Empire Ears EVR if you compare the highs. Straight up beating Rai Penta and EVR in terms of highs iirc.

    Staging and Imaging: pinpoint imaging but not exceptional.

    Soundstage: Width; very wide! Depth; Average :)

    EarTips: I prefer best with balance tips that comes in the box. Yes, with N6ii pairing or EQed Spotify to mimic N6ii signature.

    Test Track

    13 Test Track Spotify Link: https://open.spotify.com/playlist/1NDXTjaSGKqIAO5vz4yTEl?si=MxnBiWh0RleJ7aAqo7I-ow

    Paint by Moonmoon: (Male vocal centric)
    No doubt, no problem for male vocals. Pleasing sound, has a great weight for male vocals. The clarity is great too! The ending part with multiple male vocals is also very musical and well separated.

    Love Alone by IU: (Female vocal centric)
    Beautiful female vocals! It has weight, air, and clarity. There is no bass bleed at all to my ears. It is not even “too forward” kind of vocals and I like how it placed the vocals.

    Angel by Chancellor and Taeyeon: (Duet Male and Female vocals)
    A very well recorded track and hence YB04 delivers it beautifully. Male and female, both sounded very good. Very airy and musical at the same time. Layering is excellent too!

    Every End of the Day by IU: (Female vocal centric with complex music)
    Hard track and happily I would say this set did well. The layering capabilities with the soundstage performance helped a lot. The vocals is again smooth and does not sound strained at all.

    POPSICLE by UHSN: (Imaging, complex, separation song)
    Imaging is excellent but not outstanding as KSE1200 but again this is super great considering its price. It handles the complex and crowded part very well. Not harsh at all and very musical.

    Occupied by Rich Brian: (Subbass and imaging track for male)
    Again, this is not a sub bass oriented IEM. However the subbass is very clean. The male vocals here are really well pronounced, crystal clear and smooth. Such a pleasing tone and the imaging is great!

    Your text by Sundial: (Soundstage and pinpoint imaging test)
    The soundstage is wide. Everything is separated well and being placed at the right places. Very beautiful tone and the male/female voice is gorgeous too. No bass bleed at all. Pinpoint imaging great.

    Bad guy by Billie Eillish: (Subbass and layering for female)
    The subbass is controlled and lean since this is not a sub bass oriented IEM. The layering of multiple female vocals is flawless. Again, the vocal performance on this set is beautiful. I stress this again, with N6ii pairing or EQed Spotify to mimic N6ii signature.

    Psychosocial by Slipknot: (Multiple metal instruments track)
    The separation of guitars, drums, etc are well presented. The vocals are well presented. There is no any weird peaks on highs that can ruin your experience. I like how it sounds.

    Feel Special by Twice: (Pop electronic music)
    Very good sounding. I love how YB04 handles electronic music without sounding harsh at all. The N6ii also helps a lot making this set even more musical.

    Blah Blah Blah by Armin van Buuren: (EDM, almost dubstep but not a hardcore dubstep)
    Not the best set for you to dance in the club however the highs are well extended without sounding harsh. It has a minimal amount of bass for you to enjoy it but other sets can do better for you if you are an EDM banger. Imaging is very good though.

    Cumbe by Rodrigo y Gabriela: (Can be a “typical” audiophile track?)
    Excellent separation for all instruments. The guitars and the drums do not sound congested at all. Bass is controlled and hence the guitar sounds clear. The imaging is excellent!

    Chicken Noodle Soup by j-hope and Becky G: (Pop Hip Hop Top 40 Hitz kinda of track)
    Sounds great on this set though it can be better with bass impact if you want to enjoy this kind of track. However, the vocals performance is always on point!


    YB04 vs EVR:
    This has been a few weeks since Ive heard EVR so, take this with a grain of salt. However I can remember that EVR vocals presentation is superb. However, the highs are a bit veiled as in it rolls of pretty early before creating airy kind of feeling. For the bass the department, I can recall that both of these sets are almost equally the same. It doesn’t have much impact on this region but lean with warmth. YB04 excels on highs since the iem extends quite a bit and give the airy feeling.

    YB04 vs Rai Penta:
    Even Rai Penta is a hybrid with a DD bass, Penta doesn’t emphasis on bass. The bass is lean and just because of it is a DD bass, I can feel the DD texture in the bass region even though it doesn’t slam that much. For the mids, I think both sets are great. The mids and vocals can be a be a little difference but both are excellent. And again for the highs, YB04 exceed the highs of Penta. It has more details but still retain the smoothness and deliver music in a musical way.

    YB04 vs IER M9:
    Straight up M9 is a fuller sounding IEM. M9 with hybrid tips sounds intimate and engaging but not really open as YB04. However, with a bigger bore tips, M9 performs outstandingly good with amount of warmth and kick and still maintain the crystal mids and highs. Pairing it with N6ii is so musical and full of emotion. YB04 on the other hand tends to be a leaner side and still have tons of warmth to make the music rich. Just the A B comparison makes the M9 fuller than YB04. Without A B comparison, I can easily say YB04+N6ii pairing is full and musical and still a great set for a detail pickup. Plus, YB04 has above average soundstage!

    The unique/Conclusion:
    This is a good example of reference tuning that still carries musical emotion to it. It has warmth in the mids and vocals that made this set sounds emotionally engaging. The soundstage in term of width is really one of the factors for this IEM, really wide and well separated sound. However, it performs the best with N6ii. Hence, I tried my best to imitate the signature of N6ii into my Spotify Apple equalizer in order for you try it. Again it is not 1 to 1 sound but the idea is there at least. Picture attached; you can try with any eq app if you have it. Also, I love to bring Ipod/Apple dongle here because that's one of the most clean neutral source for me to know the benchmark of a specific IEM. Again, YB04 is a reference musical sounding with excellent vocals delivery!
    -EQ for Signature imitation-
      project86 likes this.
  3. skedra
    A take on reference tuning
    Written by skedra
    Published Nov 10, 2019 at 4:11 PM
    Pros - Well balanced mids and highs
    Wide and airy stage
    Good timbre
    Great accessories
    Cons - Lack of subbass extension
    Not enough bass in general to be an all arounder
    Average fit due to size
    Big thanks to AndyKong for sending the YB04 over for review.


    The YB04 has been burned in for 100h prior to critical listening. Majority of the listening has been done using Cayin N6ii with both A01 and T01 boards.

    Packaging & Accessories:
    The IEMs come in a fairly big box with a fair bit of weight to it.

    The presentation feels very premium, with everything being well secured and thought out.

    The amount of accessories is quite impressive, especially when it comes to tips choice. Having 5 types of tips to try with the IEMs is a very good starting point to both get a good fit and tune them sonically.

    Build Quality
    The build of the IEMs is solid, the shell is smooth and well machined. The coating feels and looks premium and should last the normal usage without issues especially if they are kept in the provided case.
    The case itself while big is very well built, needs a good amount of tension to open and close so it shouldn't open accidentally.
    The cable is a bit weighty but the ear hooks help to relieve dissipate both its weight and the weight of the IEMs.

    Unfortunately for me, the fit was average at best. The size of the shell made it quite finicky to get a good seal and keep the IEM comfortable in my ear. This is obviously something that will vary from person to person but you should consider those are fairly big.
    For reference pictures next to CA Andromeda:



    Subbass extension is fairly limited, listening to songs like "Bonefield - Window" you can tell the notes die out way too early and don't fill the stage the way they should. The midbass is quick and snappy but lacks the punch and can feel anaemic at times. This definitely doesn't render those IEMs quite genre-specific and if punchy bass or good subbass extension is needed then they aren't a good choice.

    Sweet and clear. No matter the source those two characteristics were always present. Timbre was very good across the instruments, notes had a decent amount of weight to them. With the N6ii, the midrange gained a nice sense of warmth and fullness which translated into making vocal-centric music extremely enjoyable. The detail was present but not overbearing or in your face.

    Well extended, smooth and detailed. Again very good timbre and transients, cymbal hits had a nice bit of sizzle to them. There was no sibilance or harshness to be found. They also produce a very nice sense of air no matter how complex the tracks are.

    Imaging & Soundstage
    The stage is probably one of the biggest strengths of YB04, It's wide and airy, with very good separation and imaging across. It's not the deepest but the width partially covers for that.

    While the tuning of those isn't something I would call mainstream, they are still an interesting offering due to their midrange and highs and general coherence to the sound. They also offer a wide range of accessories and good build quality. My main problem with them is the bass, I can understand the tuning nature of it however, the subbass extension is quite disappointing at this price point. The fit could also prove problematic for certain people so I recommend you demo those before purchasing if possible.