COZOY HERA C103 — comfortable fit and relaxing sound



HERA C103 — first and the only IEMs from COZOY — a brand known for good portable DACs and AMPs with great crafting and premium materials. HERA IEMs follow the mainstream of the brand design guidelines — look pretty, fit comfortably and perfectly build. Main intention of my review is to go into details and investigate whether HERA C103 can compete with other IEMs more oriented towards this kind of products. Personally, I have no doubts that it would — COZOY is a good brand according to the feedback from customers about their DACs — just want to check and share the thoughts about their first extrinsic try.


Buy COZOY HERA C103 at PenonAudio store

COZOY HERA C103 technical specifications:

  • Type: single dynamic driver IEMs
  • Driver unit: φ9.2mm, ultra-wideband dual layer membrane
  • Sensitivity: 103±3dB @ 1kHz 0.126v
  • Frequency response: 10Hz — 20kHz
  • Impedance: 32Ω ± 15%
  • Rated Power: 2mW
  • Audio cable: 1.2m, OFC, copper silver-plated, teflon skin
  • Plug: 3.5mm


Packaging, design and materials:

HERA C103 IEMs come in folding black matt box with white cardboard slip cover. Cover contains product name, picture and full technical description at the back side.


Box itself is more strict, with only a brand name filled by silver paint. Top cover is retained by a strap at little more than 90 degree angle when unfolded.


All inner compartment is covered by black velvet fabric.

Box contents:

  • HERA C103 IEMs + Audio cable
  • Protective case
  • 3 pairs of silicone eartips
  • 1 pair of memory foam eartips


Leather storage case is quite unique in terms of design — haven’t seen the same from other manufacturers. Very neat and the build quality is excellent. Large enough to carry IEMs together with all set of eartips and many more…


HERA C103 IEM shape remind of ancient vase if placed vertically. Shells are made of two pieces of polished steel, perfectly aligned together. One of the design elements that greatly improves the overall look is a pattern of lines at the bottom and side notch filled by promegranate color.


Without those elements HERA design would not look that interesting and complicated. There are 2 compensational openings on the shells: one is close to output nozzle and another one is on the edge of the shell notch.


Ouput nozzles have unibody construction with top part of the shell and also feature special grooves for retaining eartips. Nozzle openings are protected by metal filter grills. Build quality is decent, shell elements feel solid and durable.


Stock OFC, silver-plated copper wire features steel Y-splitter, limiter and audio jack housing.  Unfortunately, this cable is not detachable but seems to be durable enough to survive some neglect use. I really don’t know what drives companies to introduce IEMs nowadays with non-removable audio cable…



Had some doubts about the fit due to heavy and shells plus the bullet-like shape. First attempt made those doubts fade away — fit is very comfortable with the right choice of eartips. The only two concerns for this type of shape are the absence of earguides and quite a protrusion from the ears. Helmets and hats should pass by… At the same time — surprisingly tight fit with no irritation. Not as good as pseudo-custom IEMs like Kinera Idun, HiFi Boy OS V3 or Magaoi K6Pro but still very usable.


Sound quality:

Tested with HiBy R6Pro DAP

Lows and midbass:

Lows in HERA are a little bit more accented than mids but since the bass is fast, tight and accurate — this accent is not producing negative effect. I would say that lows are in a perfect balance and there is no need to either reduce or increase the amount. Texturing is on a better side making you pay attention to micro details of bass notes. The extension is not that great but compensated by resolving power and speed. Separation with other ranges is decent with good quality tracks. If the quality goes down — there is some mixture with and shadowing of mids.

Midbass sounds powerful, tight and punchy with a bit more than necesary treble influence that makes smaller drums stand out of the mix. Far from being distructive but noticeable in the tracks that are prone to such sounding. Example: Dire Straights — You and your friend (main tempo beat).


Mids and vocals:

A little emphasis on lows that was mentioned before is doing a good job and adding a touch of warmth to the mids. This improves the perception of both — male and female vocals in terms of thickness and also masks out female vocal harshness and lisping. As the result — tracks which would usually sound annying at higher volume due to striking female higher notes gain get the appropriate treatment and perceived more neutral and calm. Calm — is a good definition to describe the sound of HERA in overall. Just a tiny portion of V-tuning to make it sound more engaging but the entire picture feels quite even. Moreover, mids are not evidently recessed and playing the main role in many tracks. Some instruments like guitars are more exposed and stand closer to the stage front which is good for many genres like rock, blues, jazz, etc. Resolution is not that impressive, just moderate, but the fact that mids are not recessed helps to pull off the attention from that.



Treble range is quite thin, clear and icy as for the dynamic driver IEMs. This is another good example of how good treble can be with the dynamic technology (first one was TFZ Tequila 1). Lower treble in HERA is more emphasized and obviously sounding more exposed than mids… but again — the complete sound picture is not suffering from that, feels balanced and not tending to brighter or thinner side. Extension and feel of trasparency is one of the best in the class. Balance with lows is perfect.



Want to warn you again — HERA are very quality-sensitive and very demanding IEMs. When the track is perectly recorded expect excellent layering between ranges, instruments and voices. Scene feels wide and deep. If the quality is not that great — depth narrows down due to mids starting to mix with lows.


Sound in overall:

COZOY HERA C103 sound could be described as well-balanced, having slightly warm timbre and a tending to darker tonality. It is perceived as being more neutral than many other rivals with more evident V-shaped tuning or heavy bright or heavy dark sound. Bass is quick and textured, mids are well exposed and moderately resolved while treble is very good for dynamic IEMs.

Compared to Whizzer Kylin:


Kylin have similarly well-exposed mids but are perceived brighter and crispier. Treble is more pronounced and extended. But lows are slower and feel to perform apart from everything else. HERA sound more complete, balanced and put together (I mean — more congregated). HERA also have much better fit.

Compared to HiFi BOY OS V3:


OS V3 are very close in sound to HERA and it is really hard to choose among those two models. OS V3 have much better fit due to excellent pseudo-custom shape, balanced and neutral picture. For me, the main difference is in better reproduction and texturing of lows with HERA and better layering and extension of treble in OS V3.

Compared to Moondrop Kanas Pro:


Another tough choice but with more evident difference in sound. MKP are great IEMs in all respects (maybe, only the fit is not that good) and one of my personal favorites. But again, as in case with Oxygen — I would prefer more calm and neutral sound, with more thickness to mids and less influence of treble. This describes the main difference of HERA IEMs which stand closer to Oxygen rather than MKP. Pity is that the resolution and extension to the both sides is not on par.



Always believed that dynamic IEMs are yet to surprize in many different ways. Some recent models based on this technology from different brands occupy the leading position in the respective classes and become bestsellers on the market. COZOY HERA C103 is not an exception — a good choice of balanced performance suitable for many genres, although quite hungry for the quality of the recordings. Some advices like detachable audio cable should be considered by COZOY in future but their first attempt towards universal IEMs is definitely very positive.

Buy COZOY HERA C103 at PenonAudio store

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