Cayin YB04 – Black belt

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.


  • 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


  • None that I can think of as long as you like a reference signature

Price : 399$
Product page :

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.

This review was originally published on :

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

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