7Hz x Crinacle Zero 2 English Review


Music for the Masses




Construction and Design




  • Smooth, fun, all-round profile that can delight the masses.
  • Musical, organic, full, rich, dense, clear and quite detailed sound for its price range.
  • Exceptional value for money.




  • Treble may be too soft for some.
  • The cable is a bit rigid and tends to get stiff.
  • While the design may be pleasing and attractive to many, it has a certain toy-like appearance.


Purchase Link




Link to the Store






The already famous 7Hz brand is once again launching a new collaboration with the famous In-Ear Fidelity founder and YouTuber, Crinacle. Of course, it’s the new 7Hz x Crinacle Zero: 2. This new model features a 10mm dual-cavity dynamic driver with a PU+Metal composite diaphragm. The result has been an improvement in bass and midrange, as well as faster diaphragm movement, giving a clearer, more accurate and punchier sound. The standard cable has also been improved by using a high-purity, silver-plated, oxygen-free copper conductor. Arranged in a coaxial structure, each wire is interwoven with 140.06 and 250.06 windings to strengthen the cable and provide better audio transmission. In this new version, the profile has been subtly changed, adding an additional 3dB in the low frequencies to gain presence in the lower range, offering a more attractive sound compared to the first version. With this, it gains in warmth, body and texture, generating more physicality and base in the fundamental frequencies, as well as avoiding bass bleed. Let’s see how much of this is true in the following review.





  • Driver Type: 10mm dual-cavity dynamic, with PU+Metal composite diaphragm.
  • Frequency Response: 10Hz-20kHz.
  • Sensitivity: 108dB/V@1kHz.
  • Impedance: 32Ω.
  • THD: <1%/1kHz.
  • Jack Connector: SE 3.5mm gold-plated.
  • Capsule Connection Type: 2Pin 0.78mm.





The 7Hz x Crinacle Zero: 2 comes in a small white box with dimensions 105x75x34mm. On the front side you can see a realistic photo of both capsules without cable. At the top you can read the model name ZERO:2 in large letters. To the right is the Crinacle logo next to the logo of the brand itself. Underneath is a short description of the model and in the lower left corner the Salnotes logo. Many elements are repeated on the back, only the photo of the capsules is smaller and underneath are the product specifications, in Chinese. At the bottom are the brand details. When the cardboard is removed, the capsules are shown in a foam mould with a cardboard decorated in almost the same way as the box. It is protected by a transparent plastic sheet that acts as a lid. Underneath this layer there is a bag containing the cable and a bag containing the silicone tips. In summary, the complete contents are as follows:


  • The two 7Hz x Crinacle Zero: 2 capsules.
  • One cable with SE 3.5mm plug and 2Pin 0.78mm interface.
  • Three pairs of spherical silicone tips, sizes SxMxL.
  • Three pairs of narrow silicone tips, sizes SxMxL.
  • One instruction manual.


For a price of $25 you can’t ask for much more. According to the brand itself, the cable and the driver have been improved. There is no bag or case to store the headphones. However, there are two types of colourful tips, the size differences of which are not very obvious.
The Zero:2 is available in three colours: Silver, Orange and Blue.



Construction and Design


7Hz repeats the shape and construction of its first Zero model. This time, however, there are fewer colours to choose from and the casing is transparent. It still retains the triangular stepped shape reminiscent of a transformer. Also the external metal plate on which the model name is displayed. The Silver version has a metallic plate in the same colour and the capsule is transparent. This is the model I am describing. The Orange version has a dark outer plate of the same colour and a dark body. Finally, the Blue model has the body in that colour. It is clear that this model has a rather peculiar shape, with the thin metal outer plate, with the letters of the model in white and a kind of pin embedded in the top corner. The capsules are made of transparent plastic, with a rather rounded shape on the inside. They allow the entire inside of the headphones to be seen, with the dynamic driver located close to the nozzles. There is a separate hole in the centre of the driver, further away from the nozzles. The entire inner face is formed from a single piece. There is a shallow letter inside a circle to indicate the channel. The nozzles are not very long, although they have an appropriate taper. They have the classic shape of two steps on a base of larger diameter. The narrow diameter is 5.4 mm and the crown is 6 mm. Their bore is protected by a metal spiral grille with a large hole in the centre. Underneath is a white filter that looks like a textile. The 2Pin 0.78mm interface is located at the edge of the capsule, fully integrated with it. The gold-plated connections are located inside a black plastic cylinder. A red dot indicates the polarity of the connection.
The cable consists of two joined strands coated with dark translucent PVC. The plug sleeve is a black, metallic cylinder with a micro roughened surface. Salnotes can be read longitudinally. The splitter is a kind of biscuit with a plastic border to match the cable, the faces of which are two mirror plates. On one is the brand logo and on the other is the model name, although the model name is barely legible. The pin is a custom-made piece in the shape of a ring, the inside of which is just the right size for the two cables joined together. It slides correctly and performs its function well. The cable has over-ear guides, but they are relatively soft and not too stiff. The sleeve of the 2Pin 0.78mm connectors has a slight curvature and its diameter grows subtly towards the connectors to end in a circular black plastic base on which protrude rectangles containing the two gold-plated pins. Each sleeve has its lettering to indicate the channel, embossed on the surface.
As a whole, the capsules are very light, and still look more like a toy than an IEMS. But I can’t say that the construction is bad, as the capsules are sturdier than they look.
The cable is somewhat stiff, though it is soft and seems sturdy. The channel lettering on both the capsules and the cable is not very noticeable.
What more could you ask for at this price? In terms of build quality and capsule design, there is a noticeable element of differentiation from other models. It is clear that its appearance is the most controversial point, but both the shape and the weight help a lot in the following section.



Adjustment and Ergonomics


As I said before, the appearance can be a bit of a criticism, it looks like a fragile toy. But its very light weight and shape fits perfectly in my ears. The nozzles are not very long, maybe they are the weak point and the insertion is only superficial. Depending on each morphology, this can be a good thing or, on the contrary, it can be a problem that prevents a correct seal. In my case, with the large foam-filled home-made tips, the fit is very occlusive and the capsules are completely integrated in my ear. Even so, I find that the mouthpieces are a bit short, as the inner side is in contact with the parts of my ears, something that, in the long run, can cause some discomfort due to the pressure exerted. Despite this, the angle of the nozzles is adequate and adapts correctly to my ear canal. The fit is immediate and there is no movement of the capsules. This adjustment allows intensive daily use, it is suitable for sports and if, as the hours go by, the rubbing I mentioned earlier does not prevent it.
With so much contact and thanks to the size of the tips I use, the isolation is quite high.







It is curious that the frequency response is much more in line with Bad Guy’s target than Crinacle’s. It even has more sub-bass than the one proposed by Bad Guy. In my opinion, the Zero 2s have a W-profile with an emphasis on sub-bass, rounded midrange and mid-treble. The midranges are not too sunken, as I say, the pinna gain is rounded and not excessive, while the treble starts with a controlled roll-off, to rise slightly later on. Overall, there is a more powerful low end that is intended to win over those who found the first Zero thin and lean in the lower range. The transition between high-mids and early treble has also been smoothed, perhaps slightly too much so. As a result, the current sound is warmer, with a more physical base, softer treble and a more limited, subtle brightness.





It’s important to put the sound of the 7Hz x Crinacle Zero 2 in perspective, knowing that they cost €27. And it’s not just because they sound good, but also because of their behaviour and level of bass performance. Without having been able to enjoy the first version, I like their tuning and I’m glad that the Zero 2s move away from Crinacle’s preferred profile. I must comment that, in general, it is not my preferred curve either (I am still shaping it…), but it is true that I prefer them as IEMS in this price range, whose use can be very all-round, daily or battle. In this sense, the sub-bass is the star and the mid-bass feels a bit bloated. Still, it saves power and the whole low end, has a remarkable presence, occupies very good volume and is fun, without reaching Bass-Head territory. It is true that its texture level is low because its development is much smoother. However, it has a good level of elasticity, without being too rubbery because it is quite compact for what it costs. It dissipates quickly, recovers quickly and has a remarkable level of dryness. It is in these aspects that the Zero 2 stands out, this behaviour is very admirable for its price. And this is confirmed in the pure tone test. The 20Hz LFO reproduction is very pleasing and enjoyable, the tone is very realistic, deep, with a good physical and sensory blend. I’ve seen much worse performances in $100+ IEMS. The Zero 2’s execute pure very low frequency tones naturally, there is almost no colouration, giving a punchy, punchy impression, as well as holding quite a bit of power without suffering. In this aspect, the Zero 2 are not intimidated by their small size and are ready to support a good volume of the connected source without complaining or suffering. This excellent behaviour, translated to real music, means remarkable performance. It may not have the level of resolution to discern all the detail, layer all the layers or accurately describe the most complex bass lines. But it can boast great performance for a ridiculously low price. Limitations also exist and these are concentrated in the fact that its technical ability is restricted, I would rather say simplified. In complex passages the Zero 2 doesn’t suffer at all, but it doesn’t show a fully reliable descriptive ability either, as it suffers from a certain level of resolution that prevents it from following bass lines in detail. It’s not fast enough to reach those analytical levels, but its representation is very convincing and, most importantly, flawless. The result is powerful, punchy, powerful, fairly clean, realistic, natural, with plenty of oomph, compact and smooth bass, which you can’t ask for anything at this price.





Once again, the Zero 2 have surprised me in a very pleasant way in the midrange performance. During my first listens I had detected a simplistic execution of the central range, without too much level of resolution. I had perceived a midrange descriptive behaviour, without too much detail. But with more selective, careful and critical listening, I have realised the great level of detail they offer for their price. First of all, the Zero 2 is not opaque at all, it has a remarkable level of separation and is capable of describing micro details in a partial way. While it is true that it is not able to develop them fully, they can be intuited in the midrange. And this is something I didn’t expect at all. It is worth noting that it does not have an analytical sound, on the contrary, its representation is smooth, as is clear from its rounded curve of midrange and slightly sunken first treble. With this fairly controlled level of brightness, the notes do not appear too thin and it is easy to detect a certain thickness in the music. However, the sound is far from being homogeneous, congested or continuous. There is more than enough technical ability to demonstrate good clarity, in a profile with a warm tendency, where the bass has a notable prominence. And, in this case, that is not achieved by energising the midrange, nor by saturating the treble. Quite the opposite, as I have already mentioned. In this scenario, achieving this level of clarity, precision and detail is only possible by creating a dynamic driver that is sufficiently resolute to offer all these sensations. And here I come back to the price, which is $25. The Zero 2s have managed to recreate a sufficiently rich sound without falling into the facile trap of advantageous tuning in that regard. And this is something that is normally reserved for much higher priced IEMS.
Returning to a more traditional description of the midrange, the first half is slightly sunken. The male voices are presented at a midrange level, though clean. The physicality of their body is relatively low and they are somewhat lean. They don’t show exuberance or too much complexity. But they are still able to deliver a certain level of punch at their base. Again, texture is not its strong suit, nor is the level of nuance, due to its smoothness. Despite this, this first half proves to be quite transparent within an inoffensive and gentle profile. In the second half there is a clear excitement, which is very much controlled by the midrange limiting of the first treble. In this way, the female voices are neither shrill nor completely dominant. In addition, the overall timbre is somewhat dry, relatively analogue, but never brilliant, on the strict and restrained side of its harmonic extension, but quite natural after all. The result is a balance that is more obvious than one might expect looking at the chart. There is a good projection of the details and nuances of this second part, but without being explicit or splashy, keeping a very appropriate level of blending, both with the vocals and the instruments, so that there is no predominance of one or the other. In this way, the aforementioned balance is maintained, as well as a sense of cleanliness, transparency and separation, without there being a clear predominance of any of these characteristics. None stands out clearly over the others and I think that the good synergy between them helps to enhance the visibility of the midrange in a quite realistic way.





The entry into the high zone is inverted, generating a slight drop that turns into the classic sibilance and brightness control phase. It continues to subtly recover and persist until the air zone. In this sense, for a dynamic driver of this price, the extension is quite good, although the treble presence is subtly nuanced in the initial phase. The result is a controlled initial sparkle but with good extension in the mid-treble. In this way, the harmonic register is enriched and the sound is dynamised so that it is not completely smooth, but with a slightly displaced, but still controlled brightness, so as not to lose balance.



Soundstage, Separation


Perhaps the Achilles heel of the low-budget IEMS is the stage and separation. In this respect, I am very satisfied with both features with these Zero 2s. Again, knowing how to relativise their outstanding price/performance ratio, the soundstage is quite spacious as it doesn’t sound congested, concrete or intimate. There is a good level of laterality, although the exposure is clearly frontal, with an average height and a good level of depth. The level of detail is not quite micro, but there is enough subtle capacity to sense an initial development. In this respect, there is also good layering of sound and nuance, which helps to recreate those midrange details. Separation is obvious, achieving a good level of clarity and transparency. It will never show an analytical character, but it has the virtue of sounding smooth, balanced, powerful in its low end and rather more resolving than the price, profile and frequency response might lead one to believe.
The positioning and imaging is more than adequate, without too much more to comment on.





Kiwi Ears Dolce


In the same price range are the Kiwi Ears Dolce. They have a similar level of construction, with a transparent inner housing and an opaque outer plate in both cases. The clear difference is in the trapezoidal look of the Zero 2, with a semi-custom shaped capsule of a very restrained size in the Dolce. The Kiwi’s look is more mature and neutral, while the 7Hz’s «transformer» design gives them a more toy-like appearance. Ergonomically, the Zero 2 has shorter mouthpieces and a rim geometry that can be uncomfortable due to direct contact with the apexes. The longer nozzles and much more rounded shape give the Dolce a higher level of comfort.
The Dolce’s cable is thicker and perhaps less stiff, although both seem to be prone to shape.
Los Kiwi vienen con lo mínimo, mientras que los 7Hz ofrecen un segundo juego de tips de silicona.
In terms of profile, the Dolce offers a more polarised mid-high profile, with a greater imbalance between the upper midrange and the upper end. They also have a slightly more bloated low-midrange and less sub-bass.
Right off the bat, the Zero 2s offer a more balanced and fuller sound across the entire range. Starting with male vocals, the difference in presence is clearly higher in the 7Hz range. The Kiwi’s, on the other hand, have a distinctly sunken sound, as well as a certain hollowness in the midrange.
The Zero 2’s bass is richer and fuller, with a more pronounced sensory capability, more power and volume, and better texture. The Dolce’s bass is leaner and more subtle. Behaviour is more realistic and natural at 7Hz. There is a clear difference in the overall tone of the two low end, with the Kiwi’s sounding slightly duller and darker.
While the high-mids are more present in the Dolce, something that enhances the presence of female vocals, as well as providing a more forced clarity and a more splashy sound, the details feel pushed, albeit less natural. There is an imbalance between the profile of the two IEMS, with the Zero 2s benefiting. The 7Hz are more homogeneous, fuller, richer, denser and plusher. The Dolce are more polarised and there is more presential distance between the elements. Meanwhile, the Zero 2 are better harmonised and show no hollowness in the sound, being more musical and natural.
The Dolce’s treble is clearly crisper than the 7Hz, which feels more controlled and nuanced. There is a more obvious brightness in the Kiwi’s although they also possess a clear control zone, but their greater presence in the midrange and longer extension into the air zone provides greater exposure and predominance of the high notes in the Dolce.
At the scene level, the Zero 2 is closer, but also fuller and wider. With no gaps and more fullness, they present a denser, more filled, but also more extended soundstage. There is good depth in the Kiwi, but the Zero 2s have a little more transparency and separation, a more defined and resolving sound, with no hint of darkness or veil, something that is a little more present in the Dolce.
In my opinion, the 7Hz x Crinacle Zero 2s are a step ahead of the Kiwi Ears Dolce musically, offering a more mature, fuller, balanced and homogeneous sound, with a more all-round profile, achieving better separation, transparency, resolution and detail. It’s also worth noting, though, that they are softer and more muted in the treble.





The 7Hz x Crinacle Zero 2 would be the first IEMS I would recommend to those who want to get started in this world, but without spending much money. They are the gateway to something bigger. With a very solid base, quite comfortable, with a very low weight, with very well executed and resolved bass, with a quite full and complex midrange and a moderately extended, but soft treble, the Zero 2 are in my top of very low budget models. To say otherwise would be to say too much.



Sources Used During the Analysis


  • Aune Yuki.
  • Tempotec MARCH III.
  • Hidizs AP80 PRO-X Red Copper LE
  • Hidizs S9 Pro Plus.