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<b>COZOY HERA C103 technical specifications:</b><br /> <ul> <li>Type: single dynamic driver IEMs</li> <li>Driver unit: φ9.2mm, ultra-wideband dual layer membrane</li> <li>Sensitivity: 103±3dB @ 1kHz 0.126v</li> <li>Frequency response: 10Hz —...

Cozoy HERA C103

  • 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

Recent Reviews

  1. cqtek
    Remembering A Classical
    Written by cqtek
    Published Apr 28, 2019
    Pros - Sub bass.
    - Depth.
    - Sound Recreation.
    - Sweet, calm and natural sound.
    Cons - Cable, it's fixed and rigid.
    - Reduced treble extension.

    The Cozoy Hera C103 are the first IEMs of a brand created in 2014, which until now designed DAC/Amps. Following their own philosophy, they have been manufactured in metal, starting from a simple ballistic type design, with some personal touches on the back. They have taken special care in the internal design of the acoustic chamber, to contribute to reproduce a natural and immersive sound, that manages to extend both the low and high frequencies, reducing to the minimum the undesired resonances. The driver used is dynamic, built with a double layer membrane of high sensitivity and ultra wide band.

    Cozoy Hera C103 01_resize.jpg Cozoy Hera C103 02_resize.jpg


    • Driver Unit: Dinámico de 9.2mm de diámetro.
    • Frequency Response: 10Hz – 20kHz
    • Sensitivity: 103±3dB @1kHz 0.126v
    • Impedance: 32Ω ± 15%
    • Rated Power: 2mW
    • Jack Connector: Straight 3.5mm gold plated
    • Cable: Fixed, length 1.2m.

    Cozoy Hera C103 03_resize.jpg Cozoy Hera C103 04_resize.jpg


    The Hera C103 comes in a medium sized box, practically square and white, measuring 174x184x62mm. The exterior design is as simple and clean as the IEMs themselves. The box has an outer cardboard cover, with a photo of the IEMs, the brand name, slogan and model on the front. On the back, there is a box giving details about the design, the material used and the cable. On the bottom of the back side, on a red background, the specifications are written. There are also some small photos with the accessories.

    Once the outer cardboard has been removed, a black box is discovered, with the brand name on the front only. The box opens like a coffer and inside all the foam moulds are covered with a velvet fabric. In the lid part, the brand is shown again, as well as the web address. In the base part, the IEMs are embedded in the mould, as well as a rigid leather-coated box. This case is shaped like a flat flask, with the name of the brand inscribed on the front. It is quite rigid, opens like a coffer and has a magnetic closing. Inside there is a zip pocket with three pairs of tips, two are black silicone, small and large size. The other pair is blue foam. The third pair of silicone tips, of medium size, comes embedded in the IEMs. The tips have a wide inner channel.

    The packaging is great for what you bring, 4 pairs of tips is the minimum required. Thank you for the beautiful transport box, made of leather, both externally and internally. But when it comes down to it, it's not very practical to use, since it takes up more space than more classic and simple ones. In addition, storing IEMs, due to the rigidity of the cable, is not a quick task. We miss a Velcro tape to pick up the cable and facilitate this task.

    Cozoy Hera C103 05_resize.jpg Cozoy Hera C103 06_resize.jpg

    Construction and Design

    The design of the IEMs is the classic ballistic form, but with an L-shaped cut at the rear. This part is finished in red with artistic patterns. They are made of lightweight, finely polished metal. As I wrote in the presentation, the acoustic chamber has been specially designed to increase the quality of internal reflection and contribute to a brighter, more natural sound.

    The cable is made of high purity silver and copper alloy, oxygen free, reinforced with Kevlar fiber. It is fixed, has some rigidity and is prone to take shape.

    All parts of the cable are metallic, of the same quality and material as the capsules. The connector is straight, small, but with an ergonomic design that improves the grip of it. The splitter is similar and there is a conical piece to adjust the cables under the chin.

    The capsules have no channel indicator mark. They are in the cable, in the plastic cover that protects the connection with them. The letters R and L are inscribed on this case, in a very subtle and unnoticeable way. On the left side, at the other end where the letter L is, there is a protuberance, to contribute to the distinction of each channel.

    Cozoy Hera C103 07_resize.jpg Cozoy Hera C103 08_resize.jpg

    Adjustment and Ergonomics

    The adjustment is free and simple, requires no difficulty and, with the proper tips, the grip is firm, does not move or fall. The smooth, polished shape promotes comfort. Insertion may vary depending on the tips used, as it is possible to use double or triple flange tips. In my case, for the present review, I have used double bridle tips, because I get a somewhat deeper insertion and thus, a closer, fuller and more detailed sound.

    Cozoy Hera C103 09_resize.jpg



    The profile is balanced with a slight emphasis on the sub-bass zone. Thus, the result has a point of warmth, but without being too dark, although the highs are soft and moderate.

    Cozoy Hera C103 Nuevo.png


    The lower zone is characterized by the clear emphasis of the sub-bass, which gives a remarkable depth to the sound. The middle zone of the range has no hump, but descends smoothly to 200Hz. In this way, the Hera lack a pronounced bass hit, but their response is more contained and abyssal. Contented, because another good characteristic is the speed, it surprises the good control that Cozoy gets with these IEMs. This virtue can also be seen in the reverberation of the bass, which is not very noticeable, proof of the good work of the internal design of the capsules. The whole is finished off with a dry, compact execution, with a good degree of precision, detail and a quite natural texture, being able to appreciate a notable stratification of the frequencies and a clear differentiation between the bases and the voices, without any interference or clouding in them.

    Cozoy Hera C103 10_resize.jpg


    The midrange stand out in their low zone for their pronounced linearity, almost flat from 200Hz to 1500Hz. Thus, both male and female voices enjoy a notable presence, thanks also to the fact that the lower zone does not have a much greater gain over the mids, but that balance predominates. Therefore, there is no pronounced sinking or distancing, neither in the voices, nor in the mids, perceiving the whole as a fairly frontal block, although it does not stand out on the basses. But the great virtue of the middle zone, apart from the good balance with the bass, is its lack of veil, the absence of mud or any kind of sensation of nasal or tinny sound. On the contrary, the vocal range sounds very natural, present in its right measure, free of sibilances, with a very real and harmonious timbre, remarkably sweet, soft and with a good dose of warmth. The clarity and separation is good, but not excellent, the Hera are not analytical IEMs, although the resolution and detail are good, the refinement is very adequate, the sound turns towards a distinctly more mellow and relaxed than sharp.

    Finally, there is a slight emphasis around the 2kHz, guilty of a certain spark and flash in the upper zone of the mids, which benefits the whole, providing the sound with liveliness, dynamics and a push to the detail and definition of the zone.

    Cozoy Hera C103 11_resize.jpg


    Low highs begin with a smooth peak between 5kHz and 6kHz, but without exceeding the overall balance of the entire frequency range. The drop is then pronounced. The result is that the highs do not enjoy a special resolution or extension, but are quite measured and totally free of peaks, penetrating edges and sibilances. But there is a lack of more extension, clarity, greater definition and air, without the sound being dark and blunt.

    In summary, the high zone of the Hera perhaps is the least balanced due to its lack of extension.

    Cozoy Hera C103 12_resize.jpg

    Soundstage, Separation

    Despite the limited upper zone of these Cozoy, their extension at the other end is notable high and compensates a certain lack of resolution, with a great capacity for depth. The good balance is also noticeable in the spatial arrangement, resulting in a simple mental location of the instruments and their situation on a stage, which is perceived semicircular, with good distance in the distribution. Thanks to this sensation of space, the sound feels clear, without definition or detail overemphasizing.

    The Cozoy Hera C103 have a special virtue in the aspect of the sonorous recreation, in spite of its certain lack of extension in the trebles, they manage to stand out in this section thanks to the rest of technical characteristics, managing to generate a moderately big scene, with a realistic and natural distribution, well proportioned, with notable depth and a more than adequate height.

    Cozoy Hera C103 13_resize.jpg


    Dunu DN-1000

    The first IEM that came to mind after trying the Hera C103 were the Dunu DN-1000 classics. Their Frequency Response is very similar. The Dunu have more global presence in the lower zone, offering more punch in the mid bass, a more bassy sound and warm in general. But its definition there is not as appreciable as in the Cozoy, getting to sound thicker. The voices in the DN-1000 feel somewhat more congested, backward, with some darkness, due to greater density throughout the midrange and greater emphasis on bass. The Cozoy sound cleaner and clearer in that area, liberated in comparison, more open and spaced, showing off their greater depth, separation and scene. The upper zone of both is smoothed, but the extension is greater in the Dunu, although the sound is somewhat sharper, with a point of greater brilliance and better defined in the Hera.

    The Cozoy Hera, to have only one dynamic driver, seem an evolution in sound with respect to the Dunu DN-1000, they improve in resolution, balance and equilibrium. In addition, they are more comfortable, lighter and ergonomic. Even the cable is better, more resistant, even though it is equally fixed.

    Cozoy Hera C103 vs Dunu DN-1000.png

    1More Triple Driver

    Other IEMs with a warm sound and treble content are the 1More Triple Driver. In this case the 1More are even warmer, darker, with less detail, less brightness and a denser and less refined sound. In the lower zone the 1More stand out for having a more pronounced mid bass, but significantly less sub bass than the Hera. Thus, they do not reach the level of depth offered by the Cozoy. Both in the bass and low mids, the 1More offer a more congested and diffuse sound. The C103, however, have greater clarity and a cleanliness that differentiates them for the better. Voices also have greater definition, more presence, clarity, timbre and better resolution than Triple Drivers, which sound more distant, dark and blunt. In the rest of the mid zone the Hera have the same virtues over the 1More, especially a greater definition, a more analytical sound than the too soft 1More, with greater predominance of distance and instrumental separation, better detail and micro detail, a more refined sound, clearer and better resolution.

    The high zone begins very contained in the 1More and that is noticeable enough in the signature of the sound, that suffers of spark and brightness. The Hera have a slight peak in the first highs that favors the clarity, the detail and contributes to the sound a capacity of resolution and light that the Triple Driver lack. In addition, it provides a better balance, equilibrium and naturalness to the overall.

    The 1More have a more congested and dense scene. The Hera boast the highest separation and resolution to clearly win the game in this regard, both in width and height and instrumental placement.

    Cozoy Hera C103 vs 1More Triple Driver.png

    Ikko OH1

    Other IEMs, whose frequency response is very similar, especially from the lower zone to the central zone, are the Ikko OH1. Both IEMs have a fairly deep low zone and similar response and performance in this range. The Hera have a pinch of more sub-bass while the Ikko have a little more accent from the mid-bass onwards. Even so, the timbre of the lower zone is not the same in both, but the analytical profile of the Ikko and the warmth of the Hera leave their clear mark on it.

    But the real differences are in the central zone. Here the Ikko are the real protagonists, first, because they offer an obvious emphasis on the upper mid-zone, this characteristic has an enormous impact on their profile. Their sound seems more frontal, comparatively more aggressive and cold than that of the more relaxed and warm Hera. The OH1s offer a finer, more analytical sound, with greater accent on detail and resolution. This can also cause it to sound more penetrating and, over time and according to the recordings, more distasteful. The Hera sound much more relaxed in this area, offering a more natural, pleasant softness and more suitable for long listening.

    The presence of the voices is similar in both, although they sound closer and more frontal in the Ikko, but the approach is different, warm and mellow in the Hera, cold and analytical in the OH1.

    In the high range, the Ikko predominate offering more presence and extension. The treble are sharper, penetrating and crunchier in the OH1. The Hera have a good balance in the lower area of the highs, but then the presence decays comparatively compared to the Ikko.

    The clarity of the Ikko over the Hera is obvious, the level of detail is superior, as well as their resolution. But this doesn't make their scene any bigger than the Hera. The more frontal and explicit sound of the OH1 takes away some depth and their scene does not widen as much as that of the Cozoy, whose separation is based more on creating a greater instrumental distance than on a separation of details.

    Cozoy Hera C103 vs Ikko OH1.png


    The Cozoy Hera C103 has a clear tendency to become a classic, the form, the design, the construction, the materials used, the dynamic driver, the almost analogical sound, even the fixed cable ... bring that old air. But it really is a renewed classic, a good example of balanced and sweet sound, which is forged by combining the excellence of the driver used and the design of its acoustic chamber. Among its virtues, its naturalness, softness, warm balance and its remarkable scene stand out. The use of a fixed cable is not a current trend and the limitation in the upper zone produces a sound sensation far from the Hi-Res fashion.

    But none of this should tarnish a good start for the Cozoy brand in its first foray into the world of IEMs, because it is undoubtedly a good classic that never fails.

    Cozoy Hera C103 14_resize.jpg

    Sources Used During the Analysis

    • Burson Playmate
    • F.Audio S1
    • xDuoo X3II

    Cozoy Hera C103 15_resize.jpg


    • Construction and Design: 70
    • Adjustment/Ergonomics: 85
    • Accessories: 70
    • Bass: 80
    • Mids: 80
    • Treble: 70
    • Separation: 75
    • Soundstage: 80
    • Quality/Price: 75

    Purchase link


    You can read my full review in spanish here:

  2. IryxBRO
    COZOY HERA C103 — comfortable and relaxing
    Written by IryxBRO
    Published Apr 13, 2019
    Pros - blanced and close to neutral sound, good bass texturing, great treble
    Cons - cable is not detachable
    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.


    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
      cqtek and Moonstar like this.


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