Smabat M2 Pro English Review


Modular Sound




Construction and Design




  • First modular earbud on the market: Its sound can be changed, after replacing several parts of the earphone.
  • The sound is improved to the M1 version.
  • Ergonomics.
  • Construction.
  • Cable.
  • Very good quality/price ratio.



  • Very few accessories.
  • Somewhat distant mids.


Purchase Link


Link to the Store




Smabat does not stop growing and innovating. After the ST-10s Silver and Gold, they are now bringing out a new product, which is more than just an iteration of their previous M1 generation. Based on the same capsule, Smabat wanted to add an interesting plus: it is the first modular earbud on the market. And what does that mean? Well, the different parts that make up the interior of the capsule can be changed. And these parts are, the drive unit (which contains the diaphragm and the outer grid) and a tuning component (a plastic disc), which can be easily changed. By changing these discs, a noticeable change in the sound can already be obtained. The sound quality, including impedance, can also be improved by welding in one of the various drive units of your choice: the ST10S Black Gold unit from 150Ω, a unit with a titanium dome, or the standard unit with a three-layer titanium diaphragm, which is the same as the ST10S Silver. As you can see, Smabat has not left anything in the inkwell and even provides a cable that improves the one in the previous models. All this at a very affordable price.

Next, we will see what this new model is capable of and how its different parts can be changed.





  • Driver Type: Dynamic 15.4mm Three-layer Diaphragm 2.0 (PEEK, PU, PEEK Titanium Diaphragm)
  • Frequency Response: 10Hz-22kHz
  • Sensitivity: 110±3dB/mW
  • Impedance: 40Ω
  • Total Harmonic Distortion: <1% at 1KHz
  • Jack connector: 3.5mm
  • Capsule connection type: MMCX
  • Cable size: 1.2m





The M2 Pro comes in a small, flat white box, with the brand logo on the top. On the back side, at the bottom, there is a black label with the specifications, model name, headquarters address and website. The dimensions of the box are as follows: 130x90x22.

A manual with instructions and specifications, written in Chinese and English, appears after the cover is removed. Under it, there is a thick white foam mould, covered with cardboard of the same colour. The capsules and silicone coatings, already classics within the Smabat accessories, are embedded in it. Underneath these silicones, there are a couple of complete foams. The mould has two flaps, one located at the top, small, inside which there is a transparent bag that contains the tuning modules and the tool that helps to remove them. The larger flap is in the centre and under it is the new MMCX cable, 4 strands of mixed monocrystalline copper. In short, the complete content is:


  • The capsules.
  • Two black silicone coatings.
  • Two full foams.
  • Two tuning modules.
  • Tool for uninstalling the modules.
  • 1.2m MMCX cable and 3.5mm gold-plated plug.


In addition, a flat bag in black leather with a clip for closing has been provided as a gift. The bag is not very big, but its size is just right for storing the earbuds. The level of protection of this type of bag is not very adequate, but the detail is very appreciated, lately, these bags are scarce.

As usual with Smabats, the foam set is unique, very reduced for the duration of these elements. On the contrary, they come as standard with the best cable Smabat has ever made and two additional tuning modules.



Construction and Design


The design of the capsule is the same as the previous model M1. It looks like several assembled cylinders, with different diameters. They are almost completely made of metallic material, including the grids. The external part of the capsule is a cylinder with a thinner and more rounded edge than the previous M1. This is the main difference. This part of the capsule is more conical than its predecessor and has the virtue of being unscrewable. The diaphragm is mounted on this part, which is called the drive unit. As a modular element, in addition to the standard one, three different units can be purchased (information taken from the website


  • M-a-1 Titanium-plated full-size drive unit: The entire diaphragm is coated with titanium material, which increases its strength, so that treble, midrange and bass are comfortable.
  • M-a-2 Titanium dome drive unit: Only the central part of the diaphragm is plated with titanium material. The treble part has excellent details, which is very suitable for songs with only voice.
  • M-a-3 Drive unit ST10s Black Gold 150Ω, reinforced titanium-plated dome: It has a strong bass performance and the treble is very clear and precise.


Continuing with the interior of the capsule, there are two tuning modules. One comes pre-installed and the other comes as an accessory:


  • Tuning module type 0: All frequencies are uniform.
  • Tuning module type 1: Makes the mids and highs clearer. It has a surface hole that differentiates it from Type 0.


These modules are not as simple as they seem, but have been designed with Micro Maze Structure technology, using 3D printing technology.


Both the parts and the headphones can be purchased at the Smabat shop on AliExpress, as well as on its website:


There it will be possible to see photos, videos and explanations, as much of the parts of the M2 Pro, as of the assembly of each one of them.


Following the description of the capsule, on its outer side, the mark is inscribed on the inside of a polished metal ring. On the underside is the MMCX connection, next to the edge. On the other side of the edge there is a white dot with a letter inside, which indicates the channel of each capsule. On the upper side of this piece, there are two slots.

The whole system of parts, assembly and accessories, is really ingenious. It is worth noting the ease with which the drive unit can be unscrewed and the tuning modules can be changed. You only have to be careful with the cables, so as not to break them, although this is not such a delicate operation either. I think that more modules of this type could be provided, allowing a quick and, more or less simple, change of sound. Changing the drive unit is not so simple, as it requires skill in soldering the cables. It is true that Smabat provides a very suitable and economical soldering iron, but not everyone has the necessary technique to perform this operation. Although, surely, the most handy and daring ones will enjoy assembling the different drive units and thus enjoy a much more personalized sound. Personally, I think that, for those who do not dare to weld, Smabat could put on sale all the combinations of capsules and different drive units.


Below I leave a link to a video, where you can see how the different parts of the M2 Pro are changed:


Another novelty in this model is the new cable. It consists of 4 coiled strands, inside which there is mixed monocrystalline copper. The coiled strands provide superior comfort, zero microphony and very high flexibility. This is a real advantage over previous cables. The 3.5mm plug is gold plated. Its sheath is a smooth, metallic, silver-plated cylinder. It has a light and rounded notch, near its upper end. The cable outlet is protected by a small transparent, semi-rigid plastic cover. The dividing piece follows the simplicity exposed, it is just a small, smooth and polished metallic cylinder. The pin is a tiny piece of rigid, transparent plastic. Finally, the sleeves of the MMCX connectors are again two metal cylinders, smooth and silvered. But this time, the outer edge is slightly beveled and has two ring shaped notches. The inner edges, near the connections, have plastic rings, whose colour identifies the channel: red for the right, transparent for the left. Finally, it is worth noting the semi-rigid coating that gives shape to the cable, for adjustment on the ear. A small velcro strip helps to collect the cable.


Building on the excellent construction of the M1, the new M2 Pro, outperforms any previous earbud design, creating the first modular earbud on the market. Looking at the capsules, anyone would say that this is a modular and removable design, since the parts are very well assembled, without separate joints or gaps that allow to notice the union of the parts. Simply excellent.



Adjustment and Ergonomics


The ergonomics are slightly different from the M1, as the edge of the drive unit is thinner and more slender. In addition, the body is slightly more conical. This makes it even easier to fit. A slightly deeper insertion can thus be achieved.

The adjustment can be done over the ear, which is how it is intended, since the cable has the famous guides. However, if another cable is used which does not have such a covering, the adjustment could be perfectly the traditional one, with the cable downwards. On this occasion, due to these slight changes, I can’t find many sound differences between the over-the-ear and the traditional adjustment. But I must say that the comfort of both positions is quite high, which is great news.







The Smabat M2 Pro has multiple sound configurations, but I’ve only been able to test the ones that come as standard, that is, with the Type 0 or Type 1 tuning module. In advance, I must say that I liked the Type 1 better. Supposedly, this module offers a tuning that accentuates the clarity of the mids and highs. Meanwhile, Type 0 makes all the frequencies more uniform. In the frequency response graphs it doesn’t look like this: the Type 0 module has more emphasis on the low mids, but has more sinking in the midrange and a higher peak in the high mids, which further polarizes its sound. In this way, its profile has a tendency towards a warm V, which has obvious voids in its central area. With the Type 1 module, this tendency is not so accentuated and to my ears, the profile gains in clarity, resulting in a more uniform, balanced and liberated sound.

The following sound considerations have been made with the Type 1 module.





The lower Smabat area is like a seal of guarantee. Although, it is true that, with each model, the brand is trying to create profiles that flee from a declared Bassy profile. On this occasion, the presence is felt, but it is not predominant, as the overall profile is more balanced.

The lower area of the M2 Pro is slightly coloured, which is noticeable in the midbass. The depth is appreciated, but to a lesser degree, partly because of the upward pressure of the bass. Even so, the beat enjoys a good amount of strength, restraint, dryness, but not too much speed, generating a low zone with some decay, without becoming rubbery. In this way, the bass guarantees a good sound pressure, but the cleanliness is not very high, being drawn in a slightly diffuse way. The texture is uniform, with little roughness in the central area. However, this is accentuated as one tends to sub-bass. In spite of this, it is not sufficient to provide the necessary detail to the drums, sounding forceful, but not very descriptive or complex. The level of depth also does not help in the recreation of planes and the resolution is simply good. A little more space is missing, both laterally and in the front, as well as a little more light, precision and better technique.

All of the above is not an impediment for the lower area of the M2 Pro to be described, quietly, as remarkable. What happens is that Smabat has set the bar very high in its previous models and one has become badly accustomed to it. That’s why the criticism has been rigorous. Although not all earbuds have a Smabat bass.





With the Type 1 module, the favour that the bass do to the central zone, is great. Because the voices can be easily detached from the lower zone, without being contaminated. The diffuse feeling perceived at the lower end has a tendency to disappear as the frequency increases. In this sense, the voices already have a better definition and a richer texture, but without reaching excellence, because the resolution remains limited. On the other hand, the timbre is slightly warm, without the clarity being total, nor the cleanliness absolute. Continuing with the voices, their body is just wide enough so that they don’t feel thin, but without being exuberant or with a lot of pulp. Their perception is soft, of medium resolution, with a low analytical capacity and a representation that turns towards the sweet-neutral side, balanced. There is not much difference between the male and female voices, as the recreation of both is very similar, without a favour being noticed towards one of them. The descriptive level of the route of the voices is not very exhaustive, given the melodious orientation of the M2 Pro. But it is true that the ending has a bright point, a slight spark.

On the other hand, the instrumentation does not differ too much from the representation of the voices, offering a very coherent sound, within the musicality of the mids. In this way, his exhibition is relaxed, fluid and velvety. The separation is not very high, giving rise to a more liquid sound, which is technically more polished and differentiated. In spite of this, the level of cleanliness improves what is exposed in the lower area, achieving a fairly free, but relaxed, pleasant, non-strident sound, with a good dose of liveliness, which differentiates it from other eminently warm earbuds.





The upper area of the M2 Pro, is characterized by having more spark than extension. Its representation is pointed, focused on the first highs, without being persistent or very marked. Within the musicality of its profile, this spark is perceived lightly, although sometimes finer and clearly perceptible. The definition of the notes is not very high, following the soft tendency of the sound. But I must insist, that they are not dark earbuds, but quite the opposite, as they have a rather free and vivid sound, with a clear tendency towards light, without a hint of veil, nor a marked congestion, beyond a slight warmth. As a result, the treble, except for the initial sparkle, is light, comfortable, controlled and suitable for long listening. Their descriptive, analytical and resolution capacity is at a medium/low level, providing an average amount of detail, without standing out for their quantity or definition. On the contrary, despite the homogeneity of the mediums, the nuances seem more obvious in the middle zone, than in the high zone, which favours a greater naturalness in the central range.



Soundstage, Separation


Like good earbuds, the sound is open, with an almost noticeable width, but limited in depth and more, in height. The scene is eminently frontal, without too much lateral space, nor much three-dimensionality. In spite of this, there is more space than congestion. Although the sound presentation is quite liquid, its cohesion is not so great to appreciate it as a continuous without a background. The silence, although narrow, is perceived slightly, providing that sensation of freedom and openness, which I have spoken of in the previous sections. And it is this quality that provides a quantity of light, which alleviates the sound and gives it an appreciable separation.





Smabat M1


At first glance, the capsules are the same, the thickness of the drive unit changes. In addition, the cable is completely new and much improved.

In terms of sound, the M2 Pro is easy to move, the change in volume between the two is clear. In terms of profile, both models (M2 Pro Type 1) have a similar profile, although somewhat warmer, with less obvious highs. Clarity is improved in the new M2s, achieving a cleaner and more open sound with more prominent mid-range and separate from the low end. More congestion is seen on the M1, while the separation on the M2 produces greater transparency and distance between the bass and mid-range. Something that has also improved is the texture of the lower area, which is more noticeable, distinguished and rough, with a more enjoyable and somewhat more forceful punch. In the M1, the treble is more subtle and thinner, with less presence. In the M2 Pro, the upper zone is drawn with more sparkle and closeness, offering better detail, more air, separation and a feeling of openness and clarity. Similarly, the scene is wider and more open, in the M2 Pro, where the M1s are more homogeneous and continuous, with more congestion, comparatively speaking. But one thing that may surprise you is the timbre of both, it’s quite similar, although the M2 Pro is more vivid, while the M1’s are duller, a little darker.



ISN Rambo  II


The Rambo II are great earbuds, which share range with the M2 Pro. Their construction is excellent and their comfort too, although they are clearly different in design, each has brought something new to the earbud scene. In terms of sound, the Rambo II has a warmer profile, with a larger, denser, closer, fuller-bodied midrange. Voices are fuller and closer, clearly present, in the foreground. In the M2, the voices are thinner, colder, with a texture that turns towards clarity, focused more on details, than on their body or performance. Clearly, the profile of the M2 Pro is more V-shaped, with the voices further back than the Rambo II.  In the latter, the lower zone has good roughness, but its presence is lower than that of the Smabat M2 Pro, with less impact and less forcefulness. Although, the lower mid-range has much more presence, something that makes even the bass feel more complete, although their descriptive capacity is not as explicit as in the M2 Pro. Going back to the M2 Pro, in this comparison, you can feel in them, a hollow in that area that the Rambo II fills so well. In this sense, the more mid-centric character of the ISN can be noticed, while the Smabat stand out in the lower zone and in the first highs, emphasizing that character more in V. The upper zone of the M2 Pro is brighter initially, with more sparkle and liveliness than in the ISN. In this way, and in a complementary way, its sound is more technical and fine, where the details and nuances feel closer. On the Rambo II, the sound is more exuberant, filling the scene in all directions. While, in the M2 Pro, the spatial arrangement is quite different, the extremes feel closer and the means more delayed, that gives a more panoramic scene, with more depth in the centre, or, rather, distance. But its width cannot compete with the greater three-dimensionality and better instrumental positioning of the Rambo II, which also has a more realistic and natural recreation.





Smabat continues to make giant steps in the world of earbuds. And now it dares to do something original, which will delight those who like to fiddle around and modify their earbuds. For a modest price, the M2 Pro offers multiple configuration options: 3 screw-on drive units and two tuning modules. They come standard with two modules and a drive unit, plus a large cable. The sound is quite good, with a slightly V-shaped profile, a signature bass, sparkling highs, and a fine, delicate midrange with plenty of clarity and light. The comfort remains sensational, as does the design and construction, which makes it easy to modify.

What will Smabat do next? I’m looking forward to it.



Sources Used During the Analysis


  • Burson Audio Playmate
  • Qudelix-5K
  • xDuoo XP-2Pro
  • HyBy R3 Pro
  • Tempotec Serenade iDSD