ISN H40 English Review


Sound Without Trap or Cardboard




Construction and Design




  • Fantastic low range.
  • Very good clarity and close midrange.
  • Very analogical sound, natural, soft, dynamic, fun, but harmonious, suitable for long listening.
  • Great cable, good accessories.
  • Minimum packaging, for me it’s an advantage, I don’t need, almost, space for storage.
  • Constructive quality.
  • Ergonomics.



  • The greatness of the low range may not be to everyone’s taste.
  • Not suitable for those looking for a bright, ultra detailed or analytical profile,
  • Slightly large capsules.
  • Driver flex may appear with some silicone tip models.


Purchase Link


Link to the Store




ISN Audio is a brand from China, whose products, until now, were very high quality cables. Recently, it took a step forward and put in the market some earbuds, the ISN Rambo, which I already analyzed in this same blog. Now, he has moved on, introducing his first IEMS: none other than mid-range hybrids, with 3BA and 1DD. The dynamic driver is 9.2mm, while the BA are manufactured in-house: one is simple, dedicated to the midrange and the other two are composite and take care of the high frequencies. The capsules are made of black resin. Their connectors are MMCX. The cable that accompanies them is the S8, from ISN itself.





  • Drivers Type: 1DD 9.2mm + Custom 1 BA for middle Frequency + composite 2BA for high frequency
  • Frequency Response: 20-20kHz
  • Sensitivity: 105 ± 3dB @ 1kHz
  • Impedance: 22 Ω @ 1kHz
  • Jack: 3.5mm Audio, 2.5mm/4.4mm Balanced gold-plated plug
  • Capsule Connection Type: MMCX
  • Cable length: 1.2m





ISN usually uses the same packaging: a simple blue box, dimensions 124x78x42mm. It is covered with a simply decorated cardboard, with a photo of the model in question on the front, as well as its name and description. On the back, only the specifications come. After removing the cardboard and opening the box, there is a classic, but very functional, transport box, with a zipper and in black. This box has a good rigidity, more than enough to protect the IEMS and the content. And speaking of the contents, the box comes completely full of accessories. I will now list them:


  • The two capsules.
  • ISN Audio S8 cable.
  • 5 pairs of grey silicone tips, with red core, sizes XSxSxMxLxXL
  • 3 pairs of white silicone tips, with green core, sizes SxMxL
  • 2 pairs of Marshmallow foam tips
  • 1 pair of black silicone tips, with green core, medium size (comes in the capsules)
  • A brush/cleaning kit.
  • A small golden musket.


The presentation is totally plain, but the accessories are very useful. Based on the good collection of tips, only some bi-flange or tri-flange are missing. Although, on the other hand, they may not be suitable for use with these IEMS, whose insertion is medium or, rather, superficial.


On the one hand, the fact that the packaging is very generic and of practically no design could be criticised. But, on the other hand, I don’t find it crazy that the brand has chosen to use the money, which it could have invested in it, to incorporate a very good cable and a multitude of tips. If it were up to me, I would opt for this second option. As long as, this philosophy, means maximizing the audio quality. Which, in fact, it seems to be the case.



Construction and Design


The capsules are completely black, built in resin, almost in one piece. Their shape is semi-custom. Its lines are smooth, very rounded. The external face has the golden logo of the brand, under its transparent surface. The contour of this face reminds the African continent. The lower vertex is thin, but its interior projection is widened until it reaches the foot of the nozzles. The inside has the typical upper vertex, which fits in the upper part of the shell, in a very appropriate way. The depth of the capsules is great, there is no doubt that they are fat, stubby. Their overall size is not excessive, but it must be taken into account, for those people, whose auditory cavity is not very large. On the back side, there is a small hole. The connection is MMCX and is completely embedded in the body of the IEM.

Finally, the nozzles are golden pieces. They have two diameters: in its lower, narrower part, its diameter is 4.35mm; in its upper, more external part, the diameter is 5mm. The length is approximately 4.5mm. Its interior is protected by a micro-perforated metal grid.

The cable that comes with the IEMS is the ISN Audio S8. It has 8 strands of 19-core OCC silver-plated (Single Crystal Copper). The connectors are MMCX, gold plated. Its sleeves are two black cylinders, with two slots around them, which have been painted in red and blue, to identify the channel. The pin is a black metallic sphere, with a blue notch on its equator.The dividing piece is another metallic and black piece, with a flattened oval shape. The connector is a generous cylinder, the external part of which has a textured surface.  It is followed by a blue groove and the smooth majority body with «ISN Hi-Fi» inscribed in pale gold.

The cable does not have a hardened coating, which gives it an ear shape. It only has a plastic coating, which serves as protection, at the entrance to the connecting cylinders.


The design is very elegant, with that almost black resin, the mark in gold letters and the rounded and ergonomic shapes. The construction offers no weak points. Both the connectors and the nozzles are well assembled. The resin used is very hard and rigid and does not weigh much, although they are not ultra-light, their weight is not representative in the ears. They are not excessively large, but they are thick, overhanging the ears.

The cable that comes is totally at the height of the IEMS, also sold separately, at a cost of approximately $30.



Adjustment and Ergonomics


The adjustment of most IEMS can be as particular as the morphology of each one. In my case, the ISN H40 fits me perfectly, it seems that they have been made to my measure. All the contours fit like a glove and there is no movement. It’s true that they are quite overgrown, due to their thick body size.

The insertion, in my case, is superficial, using smaller tips, I could make a slightly deeper insertion. But the best adjustment and the best sound, I have obtained with the bigger tips, getting a very high sealing sensation, a quite high soundproofing and a very full sound sensation.

The only drawback was the «driver flex» effect in the left ear: due to the perfect fit I get, a kind of vacuum is created, which facilitates the appearance of this effect.







The profile of the ISN is warm/low profile, it could be considered in L. But its quality has a tendency towards naturalness and a very analogical sound.

I must clarify that, with the tips provided, the sound achieved is very good. But, particularly, I have found that the association with JVC’s Spiral Dot tips has given me a higher level of clarity and detail, without losing any bass.





All the fans in the lower area should bring their chairs and surround the H40, listen to them carefully and, why not, with admiration. Well, it’s a way like any other, to open up the comments about the bass. Exaggerated? Maybe, but these IEMS have totally satisfied my bass needs, both in quality and quantity. I’m sure there will be better ones and I will have to compare many to find them. But you must always take into account the price range where these IEMS are moving.

The ISN H40 are bass IEMS, no doubt about it. I don’t agree that they have a balanced or neutral profile. A low quantity like the one produced by these IEMS, cannot be considered trivial. But, neither does it produce a bloody imbalance, nor do they embed the voices, or drown out the highs, far from it. Their deep, clean and fast approach gives them a special sonority. In conjunction with the excellent punch control, its authority in the sub-bass (also in the rest) and the dynamic ability, makes the lower zone of the ISN, a true festival of quality and quantity. The punch is very contained and of good speed, tight and dry, it is practically colorless. It feels like a perception, giving the sensation of moving a lot of air, as if it were a studio monitor, but high-end. It surprises the technical ability that it has, to reproduce complex passages, without losing control, boasting agility. In addition, and in spite of the authority that he treasures, the bass are very benevolent with the middle zone. Perhaps that’s why you can think of a certain balance or neutrality.

Lately, I have been thinking that there is a tendency among IEMS with very good performance in the low zone, to cement their power at the deepest end: in the sub-bass. The H40 is no exception in this respect and that detail does not go unnoticed. The bass never feels swollen, nor does it dominate beyond its limit, but runs with analog precision, lots of definition and great cleanliness. It’s like describing the bass I was looking for…





My compliments to the lower zone increase, when it is time to talk about the central zone. Because, it is praiseworthy how, a lower zone full of authority, is able to have so much respect for the midrange. In my opinion, another key is the excellent location ability of the H40. This virtue allows the ranges and frequencies to be distributed spatially, without them overlapping or getting in the way. Thus, the bass can sound hard, while the voices are recreated free and close, or rather, in their place, with total naturalness. In this way, it is easy to distinguish how the singers move through the composition, approaching, moving away or moving horizontally around the scene. Continuing with the voices, I think their favor falls on the side of the female ones, as they feel gently emphasized. Their brightness is very light, as their tendency is warm, a quality that gives them a wide, sweet and velvety body. The projection of light is quite neutral, there is not a great amount of brightness, but neither is there darkness, giving way to a very realistic air and a very analogical look. What they do produce, the H40, is an enormous clarity and cleanliness in the reproduction. In addition, its definition and resolution is very good, but not analytical, reinforcing the natural and, again, analog feel of the playback.

The instrumentation blends perfectly into the scene, with a remarkable feeling of fullness, except in the highest area, where there is a slight thinness, due to its great smoothness. Its location is excellent, with great distance and air, remarkable resolution, but the detail is not excellent, despite being very good. I appreciate that the micro detail is slightly limited by the smoothness of the profile and its non-analytical and analogical aspect.






The upper zone brings up a difference between the warm IEMS I have previously heard or analyzed. In order not to fall into a V-profile, the highs are presented in a smooth and gentle way. Thus, the profile remains warm, but clear, very natural, with that analogical sparkle. Hence, the sibilance tends to zero. But, on the other hand, its quantity and extension is such, as to avoid that its sound provides some hint of darkness or lack of detail. First, you must forget to look for an analytical character in the H40, despite its 3 BA drivers, its sound is very defined, but conveniently polished and smooth, so as not to stray from the harmonious line of its predecessor ranges. The treble is very safe, not at all penetrating, it has delicacy, but sweetened, without itching or incision. The zone is moderate in its initial part, but it is expressed released and with enough air above 10kHz.

Those looking for a markedly high-pitched sound will not find it on the H40’s. ISN has even created IEMS that are capable of playing passages markedly saturated in treble, (like the «Production» album by «Mirwais») with a very pleasant smoothness and realism, giving the sound details and measured, harmonious flashes, but without missing much.



Soundstage, Separation


The warmth doesn’t have to be at odds with the size of the scene. ISNs take advantage of every micron of their enclosure to recreate a large, remarkably airy stage with plenty of separation. As I said before, the location capacity that is able to generate these IEMS, is almost excellent, virtue that helps to widen the scene, giving it, in addition, enough height. The image, in my opinion, is not totally surrounding, but it has a frontal and semi-spherical predominance. Perhaps, it is due to its natural quality or perhaps it is this fact that gives it that dose of realism that H40s possess. Be that as it may, the ISN take advantage of all its potential in the lower zone, to expand the sound in multiple directions, as well as the amount of air they are capable of generating, to locate the elements well separated, defined and located. Possibly, the H40 are one of the best bass IEMS with scene and separation that I have been able to analyze, outstanding, for its price range.





NS Audio NS5 MKII Extra Bass


I’m going to start with a complex but necessary comparison: the NS5 is one of my favourite IEMS, a true single DD delight, with a lot of detail and a realistic profile, but more analytical and brilliant.

The first differences are very clear, the NS5 need power to shine, while the H40 show all their power with much less, and their power is demonstrated in that comparatively low area thundering. On the NS5, the voices are much more in line with the bass, even standing out above it. Likewise, both the details and the highs have a higher presence. The NS5s are more focused on offering a richer sound, based on the mid-high zone, being more explicit and surgical in many aspects, but without losing the naturalness, nor sounding artificial.

If we talk about the lower zone, the differences are very big in quantity, to get an idea: in the NS5 you have to look for the bass line, while in the H40, this one chases you, catches you, drags you, floods you or hits you. The drums sound thinner on the NS5s and, in general, the mid-low zone suffers from this certain lack of body, comparatively speaking. The opposite is true of the upper middle zone. In the NS5 it is much more explicit, offering many more details, something that can be noticed in the voices, which sound richer, more defined, with more light, clarity and ornamentation. In the H40, you can appreciate the fading and a more pronounced smoothness, which hides nuances, like the breathing of the vocalists. Something else is equal in the male voices, although the projection and greater emphasis, falls from the side of the NS5, offering a better technique and constructive ability, in addition to a more prominent presence and greater prominence. Something similar occurs with the instruments, the way in which the NS5 shells the details, is well ahead of what the H40 offers. It is true that the NS5s «bite» much more, since their highs are very fine, and they can penetrate much more than the H40s. The upper zone is approached differently, in both IEMS: in the H40, the highs follow the wake of the mids, offering a smooth and soft presentation. While in the NS5, the treble has a greater presence, finesse, delicacy, complexion, resolution and definition.

The two IEMS have a way of describing naturalness, from opposite points of view. The H40s are based on a colossal and authoritative low range, to set the pace in the rest of the ranges, offering a warm and smooth profile, without darkness, but comparatively duller, without offering so much information in the details and nuances. The NS5’s sound is based on an outstanding technical ability, which allows them to extract a great deal of information from the sound offered, as well as a high level of nuance and micro detail.

The scene is also difficult to compare. In the H40, the scene is expanded by the low zone and the large location of the elements. On the NS5, the greatness of the scene is explained by the large amount of information it expresses, as well as by the great separation it has. I personally think that the scene is slightly larger in the H40, while the separation and the amount of air is better in the NS5.



Oriolus Finschi


Other IEMS with a similar profile are the Oriolus Finschi. Perhaps their profile is even more downward, with the mids more distant, relatively speaking. And that’s the first thing you feel after comparing them, not so much a difference in the low zone, but the difference in the voices. Another big difference, is the sensitivity: the ISNs move much more easily than the Oriolus.

Starting with the low zone, the pitch of each IEM is different. The H40 has a more natural and analogical color, while the Finschi does not show such an explicit or clear face, its sonority is more dull. Despite the weight of the lower zone of the Oriolus, the hitting that the ISN generate is more forceful, with more dryness and containment, but more authoritarian. The Finschi play the bass in a more rubbery way, they are longer, expansive, and flood the scene more, due to a slower recovery. It could be said that the lower zone of the Oriolus, «stains» more, lasting more in time and sound.

As I said at the beginning, in the middle zone, the differences are bigger. Starting with the voices, you can see a greater depression of them, in the Oriolus. Their body is less full, they feel more veiled, more sifted and more distant. Their tone is not so realistic, it is somewhat darker. There is more light and presence in the voices of the H40, a greater dynamism and tangible beauty, due to the better articulation and skill in reproduction. In the female voices, there is a tendency to match, although the greater imbalance in the Finschi persists. In the ISN, they gain in clarity and closeness, sounding quite complete, with more nuances and a greater descriptive capacity. The instrumentation follows the same pattern, only the lower middle zone excelling in the Finschi.

The treble has a different sonority in both, although, in the two, they are quite softened. But in the Oriolus, some flashes escape that can be a little annoying in some tones. The H40, on the other hand, has a more homogeneous and softened high zone, not so penetrating at times. However, the perception of the treble is more complete in the ISN, showing a higher overall clarity, which generates a sound with more detail and resolution.

The scene is quite good in both, but the greater sense of remoteness in the Oriolus, as well as more precise placement and the greater cleanliness in the sound of the ISN, tips the scales towards them. The H40 scene is more three-dimensional than that offered by the Finschi, which have less height and a less spherical feel.

The separation, for similar reasons, as well as the better resolution and better defined bass, also feels superior in the ISN H40.





ISN is very clear on how to make earbuds or IEMS. He has already demonstrated this with ISN Rambo earbuds, attacking the weak point of the PK capsule, offering a tailored profile. With the H40, he has created a warm, very natural and analog IEMS, improving those areas of conflict, in this type of profile: the resolution capacity, clarity in the midrange and the level of detail offered. In the lower zone, it is difficult for these IEMS to have a rival, being at the level of TFZ, without a doubt. But, in addition, they have a scene whose size is unattainable, in a headphone of their price range and characteristics. And, of course, the cable that comes with them is a big one, from a brand that is dedicated to it. Perhaps the packaging is not what many people expect, too simple and insipid. But why do I want cardboard or plastic, when they are offering me a great level of sound and more than decent accessories? Well, more sound and less cardboard. Keep it up, please, gentlemen of ISN.



Sources Used During the Analysis


  • Burson Audio Playmate
  • JWD JWM-115
  • Tempotec Sonata iDSD Plus
  • Tempotec Serenade iDSD
  • F.Audio FA3
  • xDuoo X3 Mark II