7Hz Sonus English Review


Hybrid Attraction




Construction and Design



  • Very good profile, with very clean bass.
  • Very clear, transparent sound, full of detail, resolution and definition.
  • Very good technicalities, analytical and descriptive ability for the whole range.
  • Good cable making replacement unnecessary.
  • Compact size of the capsules.
  • Low weight of the capsules.




  • The flat cable may not be to the taste of some enthusiasts.
  • It is possible that the protrusion at the end of the inner side may cause some discomfort.


Purchase Link




Link to the Store






Everyone knows 7Hz for its IEMS Timeless, one of the most famous planar IEMS on the planet. It was not their first model, but it was the one that made the brand known and positioned it in the market. From that model came other similar ones, planar variations like the AE, others similar in shape like the Eternal, even Crinacle contributed with the Salnotes Dioko model. Although it also has different IEMS such as the economical Salnotes Zero and the bassist Legato. On the eve of the worldwide launch of the Timeless II, 7Hz has come up with a new model in the sub-$60 range, which happens to be the first 1DD+1BA hybrids. Let’s see what the Qingdao brand has to offer in this hybrid IEM model.





  • Driver Type: 1DD 11.3mm + 1BA
  • Frequency Response: 10Hz-20kHz
  • Sensitivity: 109dB/V@1kHz
  • Impedance: 30Ω(@1KHZ)
  • Channel Difference:
  • THD: <1%/1kHz
  • Jack Connector: SE 3.5mm gold plated
  • Capsule Connection Type: 2Pin 0.78mm.
  • Material: Medical grade material capsule interior + aircraft grade aluminium rear face.
  • Cable: High-end silver-plated OCC (49 wires per core, 4-core stranded cable).





The Sonus 7Hz comes in an elongated box of size 170x112x47mm. The front side is divided into two colours, the left side is matt red, with the model name in large vertical white letters, as well as the model description in the same direction but much smaller. In the centre you can see a real capsule, without cable. The right side has a white background. The brand logo is at the top in silver letters on the same matt red background, forming a rectangle. At the bottom is the model’s slogan. On the rear face is an internal exploded view of the capsule, inside a rectangle with a white background. Around it, the background colour is still matt red. At the top is the brand logo and the model name, accompanied by the model description in white letters. Underneath are the specifications, as well as the brand’s contact details. Everything is written in Chinese.
Removing the outer cardboard reveals an orange box with a diamond texture and the logo in holographic silver ink in the centre. Lifting the lid reveals a fuzzy transparent plastic protector with the brand logo in silver, as well as another slogan on the product. Underneath are the capsules inside a white foam mould, with the cable attached. At the bottom is a black leatherette case with an envelope-shaped opening with magnetic closure. Below it is the rest of the coiled cable. Inside are the rest of the accessories. In a nutshell:


  • The two 7Hz Sonus capsules.
  • Black imitation leather pouch.
  • Three pairs of blue silicone tips, sizes SxMxL.
  • Four pairs of white silicone tips, sizes SSxSxMxL.
  • Four nozzle grids in the shape of flower petals.
  • Four uniform, dense nozzle grids.
  • One cable with 2Pin 0.78mm interface, four flat strands and straight SE 3.5mm gold-plated connector.
  • Instruction manual.


The truth is that for the price the packaging is quite attractive and attractive. The level of accessories is fine, although I am more in favour of the zipped cases for their better storage and airtightness.



Construction and Design


The design of the Sonus is not classic for any IEM and that is something you can always thank 7Hz for. The capsules have one side completely flat while the rest is almost semicircular, with a slightly rounded apex shifted to one side, to save the ergonomics of the ear. The external side is made of aluminium and can be chosen between 3 colours, black, red and grey. On the flat side of this face, there are two straight grooves which allow the nature of the material to be seen. In parallel there is a wave that runs down towards the apex of the face, passing through the inscription of the brand logo. On the thick edge of the flat face is the 2Pin 0.78mm connection interface. It is a round piece of black plastic completely integrated into the capsule. The connections are gold-plated and there is a red dot to indicate the polarity of the cable. The inner side of the capsule is transparent and made of medical grade resin. The colour of the capsule is integral. The inner shape is compact with a bulge at the end, a central valley and a relatively long, fairly vertical mouthpiece. It is composed of 3 different diameters, at the base it measures 6.2mm, at the narrowest centre it measures 5.5mm and the rim measures 6.3mm. The mouthpiece is protected by a golden grid with 6 petal-shaped holes. In the centre of the inner face there is a hole, in line with the centre of the dynamic driver. There is another hole towards the edge. In the valley of the inner face there is a letter inscription indicating the channel, but it looks really bad.
The cable consists of 4 strands joined in parallel, resulting in a flat cable. The outer PVC is transparent, while the conductor is high-end silver-plated OCC. It consists of 49 wires per strand, 4 strands in total. The sleeve of the gold-plated 3.5mm SE plug has a transparent part, divided by a diagonal to another part with a silver-plated metallised jacket. The cable runs flat out of the sleeve. The dividing piece is a flat round piece with a transparent plastic exterior and a mirrored inner side, in the centre of which the model name can be read on one side, while the other side has the brand logo. The pin is a small transparent piece that holds relatively well. The cable, after the division, remains flat and is shaped over the ear by a semi-rigid transparent sleeve. The sleeve of the 2Pin 0.78mm connectors is a curved, translucent plastic sleeve. There is an inscription indicating the channel on each side, which is difficult to see because it is not coloured. The two pins protrude from a narrower base, so there is a small distance between the thick interface sleeve and the capsule.
There is no doubt that 7Hz surprises with its designs. With the Sonus we are in a distinctive design that stands out for its three colours and for the semicircular shape of the outer face of the capsules. The wave-shaped surface of the outer face and the contrast of the two grooves with the brand logo also stand out. The capsule is thick but compact and quite light. The cable is another eye-catcher, very eye-catching due to its flat shape with the four parallel strands and its striking silver-plated colour. The combo is truly remarkable and does not require a cable change, unless you are looking for a balanced connection.



Adjustment and Ergonomics


Despite the thickness of the capsules, the size is compact, almost concentrated. The mouthpieces are quite vertical but the insertion angle is good and I have found no problem using my home-made foam-filled wide-core tips. With them I get a very occlusive fit, no movement, no rotation. The protrusion at the end does not go all the way over the antihelix and this can be a problem for some, depending on the level of insertion that can be achieved. In my case, with a shallow insertion there is no problem at all. However, as the hours go by you may notice that the small continuous rubbing becomes a subtle discomfort. If the capsule were less compact and slightly longer, the antihelix would be easier to overcome. Or perhaps it would not have been necessary to raise the protrusion and leave the inside of the capsule with a rounded shape.
The over-ear cable is unobtrusive and the low weight contributes to the comfort. Although this is not complete due to the point mentioned above.







The Sonus 7Hz has a pleasing and attractive U-profile, with a clean emphasis on the sub-bass end, as well as slightly exposed mid-highs and controlled, but well extended highs. The first part of the midrange is somewhat lean, while the second half is more elevated, enhancing clarity and a certain level of sparkle that makes the sound more exciting from the centre onwards.





As a good tuning excited in the lower frequencies, the bass is presented cleanly and without intrusion into the mids. Although the punch and bass are felt, the mid-bass is very little swollen, so the low end does not rumble, nor does it have any rubbery feel. On the contrary, it feels agile and free of colour, something that is corroborated in the pure tone test, where the sub-bass below 40Hz remains sensory and well-executed, while above that it maintains naturalness and realism. The gradual descent into the midrange and the good speed that the driver possesses gives it a descriptive, crisp, resolute and remarkably well-defined character to the lower range, but without feeling heavy. It responds very well in electronic music, but without being invasive or overbearing. It would never be a bass-head model because the weight is fairly evenly spread across the entire band, with quick dissipation and very little damping. There is energy, but the punch is not very voluminous, which is classic for a tuning where the maximum is at the sub-bass end. It is remarkable for generating a good punch, a certain level of presence and a fair amount of depth. But it is not enough to produce a high volume that saturates the space or swells our ears. To be sure, the performance is polite, quick in its transients, discernible in its layering and very effective in portraying complex, dirty and overloaded bass. Almost canonic in these complex situations. Very good.





With a tuning that manages to disconnect the bass from the first half of the midrange, the consequence is a somewhat lean initial phase of the midrange, especially when the mid-highs are more exalted. The sense of clarity, transparency and definition is enhanced by this situation, but even strengthened by the use of the BA driver created by 7Hz, which achieves a very high level of resolution, definition and descriptiveness. There is a clear contrast between the low-mids and the high-mids. While the initial phase is smooth, mid-distance, slim, with a somewhat thin body and a medium-low physicality; the second grows somewhat abruptly, generating a sense of stretching that separates the female voices from the male ones, even exciting the details in front of the lower fundamental. It is true that this contrast remains within the parameters of musicality and balance, but it is also true that some sibilance escapes, the result of the sharpness of the notes, their thinness and energy level, which can generate a rougher and more penetrating high phase, in the foreground, as opposed to a softer first half, relatively more distant, of low density and not very powerful. In this sense, the Sonus are not warm, but vivid and sparkling, with a more analytical and defining quality. The level of detail, while obvious and insightful, does not rise above the music, remaining resolute, though not over-excited or over-predominant. There can be a power struggle in this sense, in some critical situations, which gives it a very high descriptive and incisive level, but always within tolerable musical parameters. It is worth noting, as I usually do in those tunings that are too soft, that fans looking for velvety or nuanced mid-highs may find the Sonus not quite suited to their tastes. However, as I say, this is a controlled inclination, which is framed in a more resolute, clear, clean, bright and transparent profile, inspired more by the detail, delicacy and finesse of the notes, than by their thickness, togetherness or homogeneity. Undoubtedly, this is an alter ego that is usually necessary, effective and also very enjoyable due to its good representational skills.





The high end is clearly projected, the treble is the protagonist, although the energy level is not total. There is a point of control in their excitement, but it is obvious that they are easily felt in the mix and are noticeable at the forefront, with a moderate emphasis but with a certain predominance that elevates them and brings them closer to the listener. The high notes are fine, well separated, enliven the detail and are somewhat incisive. They accompany vocals better than instruments, as the latter add a liveliness that gets out of control at the limit, sounding harsher, less docile, which is common for the BA driver the Sonus is fitted with. This is undoubtedly a lesser evil, but it does not tarnish a tuning that was generated to enhance the clarity and transparency of the whole. The extension drops off just enough to maintain the level of power, supported by the projected character of the BA driver and extended to the air zone, where it suffers from a point of grace that could be higher. The result remains natural, even pleasant. The incisiveness is not hidden, but it fails to transgress the mix, being ultimately placated. But both the level of resolution, definition, finesse and that point of delicacy at times, give the top end a moderately crisp, expressive and bright appearance. Just enough to be enjoyed without becoming piercing or overly incisive. Quite good.



Soundstage, Separation


The scene is wide and separate, rather than deep or high. The laterality is obvious and the good level of transparency offers a sense of space that enhances the volatility of the music, as well as the expressiveness of the details. There is certainly a gaseous perception that helps to expand the notes in the environment. But it also contrasts with the low density of the atmosphere. In this sense, the music is not very full-bodied, hence it feels vaporous, but at the same time it is very distinguishable, open, clear and diaphanous.
The background is clean and the notes are well broken down, but the volatility of the scene implies an image that is infected with a certain instability when it comes to positioning, because of that same vapidity.
On the other hand, the technical performance is quite good. Note execution is powerful and fast. The dynamic driver is fast and feels supported by a very clean profile in the low end, which helps in this regard. On the other hand, the BA driver enhances that speed by providing extra energy and finesse, while respecting the eloquent balance of the whole. The Sonus achieve a good level of micro and macro detail, without putting an absolute emphasis on them and without placing them above the rest. In this sense the mix is quite pleasant, within a vivid, expressive and well-intentioned analytical musicality.





Tri Meteor


The Tri Meteors are priced at around $100, which is clearly higher than the current 7Hz Sonus, which are priced at $60. The Meteors are also hybrids using a beryllium-plated 1DD and a Knowles ED-29689 1BA. The level of construction is similar, both in resin, although the Sonus uses an aluminium outer plate, while the Meteor is all-resin. The capsule of the Sonus is more compact, somewhat smaller than that of the Meteor. However, the ergonomics of the Tri is better, the shape of the inner face fits more and better to the morphology of my ears.
In terms of sound, the Tri’s are warmer and softer. A quick switch to the Sonus reveals a brighter and more excited mid-high profile up front, despite the similarity of their frequency responses. The Meteors are subtly easier to move, but the difference is small.
The Meteor’s bass is bigger, with more extension and texture. The Sonus bass is a little drier, a little more restrained, smoother, though a little cleaner. The Meteors sound a bit deeper, more sensory, natural, darker in colour and less coloured. The Sonus have a very good technical performance in the low end, they are fast, they have a little bit of a kick to them. But those who enjoy bass will find in the Meteors a soul and a certain power that the Sonus do not offer.
The warmer midrange of the Meteors offers a sweeter, more melodious sound on male vocals, which it gives more body and physicality. On the Sonus this first half of the mids is cleaner and more transparent, but also thinner, leaner, but also more excited and sharper, with less base. It is clear that the details seem more splashy on the Sonus, and it is true that they are noticeable at first glance, because the music feels more naked and detached. The Tri’s are somewhat more homogeneous and melodious, but are also capable of presenting a good level of micro detail. But the Sonus’ sharper edge and more analytical profile gives them greater visibility. The instruments sound fuller on the Meteor, with a more natural, calmer timbre. While the Sonus’ edge makes them cooler, yet with greater resolution. Something similar happens with the female voices, which are more projected and isolated on the Sonus, with a higher brightness and edge, as well as a higher energy. Female voices on the Meteor are calmer and less susceptible to sibilance.
The Meteor’s treble seems more balanced and more balanced all the way to the air zone. The Sonus start more excited, their projection and elevation is higher in the initial stretch, with a thinner and more penetrating edge, more untamed and cooler. They are crisper, but more piercing as well. Then they seem to have a bit more air, where the Meteors are a bit more clipped, but they sound more natural and pleasing to my ears, as they don’t have the metallic edge of the Sonus.
The separation of the Sonus is very good, with a dark and discernible background. The notes are very well outlined, though thin. The sound is not cohesive, but rather scattered and volatile, creating a sense of scene expansion and projecting it to the edges of the head, but especially the details. Meanwhile, the Meteor has more depth, less separation, but, overall, the scene is more expansive, though somewhat more intimate and closer. You don’t get the sense of hollowness and open space that the Sonus do, but they generate a more forceful corporeal and physical sensation that the 7Hz don’t allow.





In this conclusion I would like to be like the sound of the 7Hz Sonus, direct and to the point. This model is possibly among the best 1DD+1BA hybrids you can buy for the price. With an ultra-clean profile, with a bass that starts from a high sub-bass, as it descends with speed towards the mids, it generates a compact and fast bottom end, with very little aftertaste, technically elevated and not without a certain power and presence. The mids are transparent, fine, analytical and very sharp. It is a lean mid-range but with a very high definition, which projects the details and the female voices. The treble is energetic and crisp, with good extension and airy feel. The stage is transparent, gaseous, volatile and projected. And separation is at its best. If you’re looking for analytical IEMS with a fairly full profile that doesn’t forget the bass, the 7Hz has plenty of numbers to end up in your ears.



Sources Used During the Analysis


  • Tempotec BHD Pro.
  • Aune X8 XVIII Magic DAC + EarMen ST-Amp.
  • Aune M1p.
  • Burson Audio Playmate II.
  • Hidizs S9 Pro Plus.