Headphoneus Supremus
Analogue Grandeur
Pros: Excellent bass response
Wide and tall soundstage
Analogue romanticism and musicality
Non-fatiguing tuning
Quality cable included
Competes above price point
Cons: Would prefer more upper treble extension
Unboxing underwhelming
Driver configuration:

1DD + 3BA
1 dynamic driver (9.2mm) – low frequency
1 BA (custom) – middle frequency
2 BA (composite) – high frequency
22ohm impedance, 105dB sensitivity, 20Hz-20kHz
MMCX connectors, ISN S8 silver-plated OCC cable included (3.5/2.5/4.4mm terminations available)

Source: Shanling M8 (4.4mm, turbo gain)
Burn in: 150hrs
Stock cable, stock silicone tips (green bore)
Genres tested: world music, jazz, ambient, electronic, classical

The ISN H40 was provided by Penon for the purposes of review and in exchange for my honest opinion. Penon have no had sight or say on content within this review. This review contains earlier impressions I’ve posted publicly and my opinion is largely unchanged from then. The ISN H40 can be purchased here.



Funnily enough, I entered the hobby at around the same time the ISN H40 came onto the market. At the time I had little knowledge of my own preferences and ended up with the Mangird Tea and the Shuoer EJ07, both had their strengths but I ended up moving on quite quickly and further down the tribrid rabbit hole. Most recently, I’ve returned to single dynamic drivers (in the form of earbuds and IEMs) and armed with the knowledge of my preference curve (somewhere between L-shaped and W-shaped) I discovered the Penon house tuning that I’ve grown to love in multiple forms.

Aware of the close working relationship of ISN and Penon, I was encouraged to try the ISN H40. Prior to receiving the H40 a part of me hoped there would be more than just a little Penon inspiration in there (in the way of mid-centric warmth), to keep me interested. There was also plenty of feedback on the forums complimenting the H40’s soundstage and bass response that piqued my interest…

Accessories & Packaging

To be straight to the point here – the packaging was underwhelming. A very thin cardboard box with outer and inner sleeves in a vibrant foil blue. Thankfully the IEMs are cushioned well within the sleeve using foam inserts. There is a functional and sturdy leatherette ISN carry case included that some might find useful. In terms of eartips there is a good selection of silicone tips and foam tips. All have a reasonably large inner diameter to encourage more treble energy through. A useful cleaning brush and cable clip is also included.

The cable – the ISN S8 – is beautifully made. It’s lightweight and has a very clear plastic sheath that reveals the silver plated OCC inside. The cable accessories are solid and well-built and the chin slider functions smoothly as intended. As a cable believer the choice of silver-plated OCC pairs well with the darker than neutral tuning to clean up and enhance the treble definition while retaining the low end extension and detail offered by OCC.




Design, Build, Fit and Comfort

The design of the shell is ergonomic and has a form-fitting shape to it. However, it’s also quite tall to the shoulder so it doesn’t sit flat to my ears and occupies all of the concha (plus more) within my smaller than average ears. It’s not uncomfortable and by virtue of the shell size and the solid resin shell the passive isolation is above average. The nozzle width at its tip is 4mm in diameter and fits nicely within the ear canal. As mentioned the shell is solid resin in a dark blue to black colour with gold ISN labelling. There is a single vent to the rear of the shell. The H40 looks sleek and is reasonably understated in its appearance. Overall, I’m very satisfied with the build but would prefer a shorter shell to the shoulder and a slightly narrower neck (before it meets the metal nozzle) to allow for a deeper fit.





The tonality here is a L-shape to V-shape with upper treble roll off. It’s got a distinctly analogue feel to it. It’s ‘musical’ rather than analytical and makes for emotive listening.

Bass: strong impact, subbass emphasis, deep extension, texture and timbre retained

The bass is the standout feature of this IEM, with some of the best subbass rumble I’ve heard. It has a fine balance of subbass to midbass with emphasis leaning to the subbass. The H40 offers up great quantity in the lower frequencies without losing detail or nuance. Subbass rumbles with authority and fills the stage very well while the midbass impact is satisfying. As the midbass isn’t over emphasised, detail in the lower frequencies are on full display and timbre of instruments is conveyed really well. Listening to stand-up bass and double bass strings is a pleasure. The DD doesn’t display the hardest impact or the quickest transients but its character is perfectly suited to the analogue-inspired sound ISN were clearly aiming for.

The rest of the tuning revolves around this strong low frequency performance.

Midrange: no shout, warm, reasonable resolution, slight recession

The midrange is interesting and not uninspired. It’s definitely not forward – something that became more apparent as I’ve spent more time with it. The large stage (another selling point to be mentioned later) emphasises a slight recession in the mids as does the restrained pinna gain. They don’t feel empty or disembodied but neither do they feel the overwhelming focus of this IEM in busy tracks. I would have preferred some greater upper mid/lower treble presence to add some bite. Tonally the mids are warm and rich and not lacking in detail or clarity. Lower midrange vocals and instruments have some great weight to them that when combined with the bass boost and soundstage gives the impression of listening to larger over-ears.

I personally have a preference for a more forward midrange with greater upper mid presence but on reflection, combining the controlled pinna gain and less aggressive uppermids with the large soundstage and bass enhances the sense of space and analogue warmth. There is an old-school ‘speaker-like’ presentation wherein the bass encompasses and supports with a very engaging atmosphere around the midrange. Thankfully, the midrange never feels cluttered by this bassy embrace and details aren’t obscured in the process.

Treble: good definition, smooth presentation, no sibilance, upper treble roll off, minimal air, some metallic undertones

The treble stays on theme in the H40. It’s smooth and controlled but not subdued. You have definition, but it’s not piercing or shrill. The tuning ensures the overall tonality remains organic, more musical and less analytical. It also allows the listener to increase the volume to bask in the joy of the low end without fear of sibilance. If I could ‘nit-pick’ I would prefer greater ultrahigh extension to balance the tuning slightly and emphasise the space even more.


Soundstage – The second selling point of this IEM just behind the bass is the soundstage. It’s large in height and width and is closest to ‘concert hall’ I’ve heard at this price range (take this with a pinch of salt as the intangibles like soundstage are very subjective). The width means the bass doesn’t become fatiguing or feel invasive and the height brings a sense of scale to the musical performance that makes it feel grand (especially classical music). It also counteracts the lack of treble air by emphasising space.

Imaging, Instrument Separation & Layering – Imaging is great for the price and the H40 gives a great rendition of many of the Yosi Horikawas tracks. There is great depth that makes layering and three dimensionality stand out.

Timbre – As a self-proclaimed timbre-head I’ve not had issue with the BA implementation here. The tuning ensures things stay warm enough and the defining bass character of the DD keeps things organic. There is the rare occasion when there is metallic timbre in the lower treble but it never put me off reaching for this IEM. I have no issue with the timbre presentation in the bass or mids. Fundamental and harmonic detail feels intact and is sustained well with no BA ‘sputtering’.


From the very first listen out of the box the H40 has flaunted a character that I’ve found quite unique and appealing. For the price (and more) it achieves a level of versatility, character and technicality that is hard to find. It quite easily sits as my choice of hybrid below $200, representing excellent value for money. ISN has created a bold and fun IEM that never becomes abrasive. It presents music with an ‘analogue grandeur’ that is as addictive as it is inviting.

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Thanks for the reply! I'm not all that into EQ'ing. I used to do it alot but part of the fun for me is finding the products that suit me as sold.
alexandros a
alexandros a
Analogue & grandeur presentation are the key words here...
The overall ambiance that H40 is able of creating of, due to it's bombastic and spacious presentation surely can makeup for the lack of air in the upper treble
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Reactions: ian91
Thanks for the review! H40 or Penon Globe is better?


500+ Head-Fier
Expansive and rich tonality, addictive musicality
Pros: Rich and warm tonality
Ridiculously huge soundstage
Powerful, authoritative, well-controlled and high-quality bass
Full midrange that doesn't lack clarity or openness
Best-in-class male vocals
Smooth and laidback treble
Very good cohesiveness for a hybrid
Excellent layering and separation
Great comfort and build quality
Good accessories for price point
Cons: Some BA timbre in the treble
Treble lacks some sparkle and air for my taste
Not the most resolving or detailed in price range
Bit of driver flex
Introduction: ISN Audio has its origins as a cable company, but in late 2019 they began producing their own IEMs as well. Their freshman entry was the H40, a 1DD+3BA hybrid which is the subject of my review today. The H40 received wide acclaim as an excellent musical hybrid with a very good price/performance ratio. At the time I was quite intrigued by the positive reviews and the value prospect, but was held back from purchasing by two things: the somewhat large shell size (I have medium-small ears), and the colored sound at a time when I was focusing my search on “neutral-ish” monitors.


However, when Penon Audio offered to send me a review sample I jumped at the chance. Were my initial concerns well-founded, or does the H40 hold up to the hype almost two years later? Read on to find out!

I would like to thank Penon Audio for providing the H40 in exchange for my honest review. You can purchase a set for yourself here. The MSRP is $195, and the specifications are as follows:
  • Driver:3 Balanaced Armature + 1 Dynamic driver
  • Dynamic driver : 9.2mm
  • 3 Balanaced Armature: Custom 1 BA for middle Frequency + composite 2BA for high frequency
  • Impedance : 22 Ω @1khz
  • Sensitivity : 105 ± 3dB @1khz
  • Frequency response : 20-20kHz
  • Connector: MMCX
  • Plug: 3.5mm audio , 2.5mm balanced , 4.4mm balanced
  • Cable length: 1.2M

Packaging & Accessories: It should be noted that ISN Audio has substantially upgraded the packaging and accessories since the initial product release. The box I received is a metallic glossy blue, and inside the IEMs are encased in foam above a cutout for the new faux-leather hardshell carry case with magnetic closure. Underneath these are the other accessories which are quite generous in quantity. Altogether the accessories are as follows:
  • ISN S8 8-core MMCX silver-plated OCC cable (buyer can choose termination)
  • Blue hardshell carry case with magnetic closure
  • 3 sets of silicon eartips (S/M/L)
  • 1 set of foam eartips (M/L)
  • Cable clip
  • Cleaning brush
I personally really like both the carry case and the cable (the black/gold hardware color scheme is customized for the H40 as opposed to the standalone cable, which is a nice touch and looks quite fetching). The included tips are quite satisfactory as well, although as usual I did some tip-rolling and landed on my expected favorite for bassy IEMs: the JVC Spiral Dots (OG).


Build & Comfort: As mentioned in the introduction, one of the reasons I didn’t pull the trigger on the H40 initially was concern over fitment, as I have medium-small ears and the H40 was reputed to be a bit on the larger size. However, I am happy to report that the H40 fits me like a glove. The semi-custom resin shells are lightweight and fit snugly and stably in my ears, providing better than average isolation despite the vent for the DD, and retaining good comfort even over longer listening sessions (those with small ears are still advised to audition these if possible before purchase, as for me the H40 is right there on the border of being too large). They do protrude significantly out from my ears, which is not a problem at all for comfort although it does mean that side-sleeping with these is out.


There can be some driver flex depending on tips and insertion technique, which I am to able to avoid almost entirely when paying attention to the latter. But overall the build quality is more than satisfactory, and I anticipate no problems with durability or longevity. The MMXC connectors are quite solid and tight.


Initial Impressions: From the very first track I played with the H40 in my ears, I was blown away by both of its two key selling points: the outstanding soundstage, and the intoxicating bass. I expected both of these qualities to be good, but not this good. The soundstage rivals even some open-backs (not something like the AKG K702 mind you, more like the Sennheiser 600 series). And the bass on this IEM is simply fantastic in both quality and quantity.

But I don’t want to give the impression that the H40 is a two-trick pony. It’s an exceptionally cohesive package, especially given that it is a hybrid unit. The overall tonality is so pleasingly rich (without any hint of over-indulgence, to the point of being thick and syrupy for example) that even excellent IEMs can easily begin to sound downright sterile by comparison. For a freshman effort and a sub-$200 price point, ISN has really hit this one out of the park.


Signature: The H40 is a warm L-shaped IEM, with a visceral and authoritative DD-powered low end that transitions smoothly into a full yet fairly clear midrange. The pinna gain heading into the upper mids is rather laid-back, and the treble is clearly the least-emphasized range of the frequency response — although I never felt like there was anything missing from the top end. The overall presentation is exceptionally musical and engaging, characterized by an inviting warmth in the lower end and an accompanying smooth and relaxed upper end that lends itself to hours upon hours of listening pleasure.

Bass: The bass of the H40 is unquestionably the star of the show. There is absolutely no lack to either extension or quantity, the latter of which is probably capable of satisfying at least some bassheads (yet without overpowering the midrange). The slam is quite intoxicating on this unit, and yet for all its power it does not lack control — especially after proper burn-in. It remains quite agile despite having a bit slower decay, which together with a somewhat softer attack lends a very pleasing atmospheric quality to the overall presentation. Note weight has a good amount of heft to it, but never comes across as overly thick or blunted. Texture is quite good, although not class-leading.

Mids: Although the mids lie somewhat in the shadow of the bass on this IEM, it is not a shadow which obscures the mids but rather which gives them an added character. The lower mids retain a moderate amount of warmth and elevation from the upper bass, leading to some of the most full and pleasing cellos, male vocals, and deeper female vocals that I have heard on any IEM. Yet this fullness does not come at the expense of clarity, and the rich expressiveness is exceptionally well-balanced with overall openness — in keeping with the thematic expansiveness of the soundstage.

The midrange in general has a good amount of resolution throughout, although the focus is much more on tonal richness than analytical detail.

As mentioned above the pinna gain is rather modest (especially by ChiFi standards), so some people might find that female vocals and certain strings occasionally lack a bit of energy, and while not recessed they can take half a step back in the mix at times. This is not so much a shortcoming as a matter of personal preference, however, and there are no doubt others (myself included) who appreciate the fatigue-free quality that results from this tuning decision.

Treble: The treble tuning of the H40 definitely prioritizes smoothness and relaxation over detail and sparkle. Other than a spike around 8khz it remains fairly polite throughout, and it is somewhat rolled off at the very top. Together with the restrained pinna gain this makes the H40 a great option for the treble-sensitive, although those looking for raw clarity and analytical detail should look elsewhere. I do think that the H40 could have used a bit more shimmer and air, but again this is a matter of personal preference rather than being an outright flaw. And I do think that the H40 shows good integrity here in remaining true to its overall ethos of musical warmth and smoothness, rather than trying to artificially augment its technical capabilities through treble trickery as can sometimes happen. Although it leans just a bit dark, as I mentioned above I never felt like there was anything missing up top.

Soundstage & Technicalities: The soundstage on the H40 is nothing short of phenomenal. Width and height are outstanding, and depth is very good as well. The full tonality as well as treble roll-off do mean that there is not a lot of air between the instruments, but layering is nevertheless quite well done, separation does not suffer, and I never experienced any congestion. Imaging is fairly good but not pinpoint-accurate. Cohesiveness is very good for a hybrid, and timbre is fairly good although there is some BA timbre in the treble at times. Resolution and details are quite decent, although again the tonality means that microdetails are not really the focus here.


vs. Penon Globe: The Penon Globe has often been cited as a direct upgrade to the H40, and while I can see what these people are saying (especially as they do share a quite similar DNA) I do not fully agree. I actually prefer the H40’s bass as I find it to be more refined than on the Globe, where it can sometimes have too thick and overbearing a note weight for some genres. The mids are a toss-up, as the Globe employs a richer and lusher Sonion BA but this comes with a correspondingly more intimate soundstage rather than the expansive feel of the H40. The treble is where I find the Globe to be more clearly superior as it has more shimmer, sparkle and air (even though it uses only a single BA for the region as opposed to the two BAs on the H40). Overall, in my opinion the Globe and H40 are more variations on a theme rather than one being a wholesale upgrade to the other. This is a testament to the value proposition of the H40 as compared to the nearly twice as expensive Penon Globe.

vs. Rose QT-9 MK2: The QT-9 is one of the other quite compelling hybrid options in the price range. While they both share a subwoofer-like low end powered by a dynamic driver, in other respects they are quite different. The H40 has greater bass quantity and a slightly more atmospheric bass presentation, although overall quality is similar. The midrange on the H40 is warmer, fuller, and more laidback, whereas the QT-9 has a more open and airy midrange as well as significantly more energy in the upper mids. The treble is more pronounced and better extended on the QT-9, supporting greater resolution, air, and detail retrieval than on the H40. Imaging is also more precise on the QT-9. However, after becoming accustomed to the H40 the QT-9 on certain tracks could come across as downright thin-sounding, even though objectively I know this is not true. All this is to say that this is a case of “different strokes for different folks,” with the QT-9 being a more balanced and versatile IEM tending towards the analytical side of things, whereas the H40 is a much more musical and full-bodied IEM that prioritizes its rich tonality over detail retrieval and neutrality. The QT-9 does however retain the unique advantage of being able to cram its 1DD+4BAs into one of the smallest and most ergonomic shells I have ever experienced.

Conclusion: The ISN H40 is a superbly well-executed IEM with an expansive, romantic, and full-bodied sound. The rich tonality lays its foundation in the powerful, visceral, yet surprisingly well-controlled bass, segues into a full yet clear and open midrange, and finally finds its fitting complement in a smooth and relaxed treble presentation. The absurdly huge soundstage makes room for every voice and instrument despite the fullness of the tonality, and overall cohesiveness is exemplary for an entry- to mid-range hybrid. Treble fanatics and lovers of neutrality will want to look elsewhere, but those searching for an absolutely addictive musicality at an undeniably compelling price point need look no further than the ISN H40.

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alexandros a
alexandros a
for anyone looking for more trebles, try to remove the clothed mesh from the nozzle, or replace the clothed mesh entirely with another with more open holes.
I did it and i cant be happier.
alexandros a
alexandros a
@thefallenangelx..... So.... You finally got it man.... And as I can see you love em as well....
For the record... It's really tempting (H40 modified) but I am afraid of destroying this gem as well......


500+ Head-Fier
Pros: 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.
Cons: 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.

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.

ISN H40 01_resize.jpgISN H40 02_resize.jpg


  • 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 H40 03_resize.jpgISN H40 04_resize.jpg


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.

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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.

ISN H40 07_resize.jpgISN H40 08_resize.jpg

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.

ISN H40 09_resize.jpgISN H40 10_resize.jpg



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.

ISN H40 11_resize.jpg


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...

ISN H40 12_resize.jpgISN H40 13_resize.jpg


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.

ISN H40 14_resize.jpgISN H40 15_resize.jpg


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.

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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.

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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.

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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.

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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

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  • Construction and Design: 90
  • Adjustment/Ergonomics: 87
  • Accessories: 80
  • Bass: 93
  • Mids: 83
  • Treble: 80
  • Separation: 88
  • Soundstage: 91
  • Quality/Price: 92

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Purchase Link

You can read the full review in Spanish here:
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Excellent review @cqtek, very well written not to be your native language. People should be more permissive and not go looking for problems where there are none (Lost in translation, like the movie). I also consider it advisable to stress that it is positive to detail in which price range we are moving. I bought this H40 thanks to your review and because I have been following you for a few years and I love your reviews and I know that you do them with total impartiality. Congratulations.
Can you, please, compare subbass with, say, Audeiosense DT600 or 7hz Timeless or Moondrop Blessing 2 Dusk? I like subbass, but hate blurred (sub)bass (with long attack and/or decay). Say, Dusk are awful for me :) While DT600 are the first in the list.
@anli I would really like to be able to make the comparisons you are asking for, but I don't have those models. I am sorry.


New Head-Fier
Pros: Balanced matured tuning
Wide soundstage
Excellent bass
Excellent midrange
Excellent Highs
Design is amazing; the gold logo kind of symbolizes how the sound feels like- Liquid gold! (smooth-sounding) lol
Cons: I don't know.

Oh wait, they mixed up the L/R cable channel
ISN H40 Review

Hello, Head-fi people

this will be my final edited review. The original unedited review was so horrible, I wanted to delete it, but I found out that there was no delete option, so now I must at least try to make this review look professional! lol

First of all, I bought this product on Penon with my own money. It was my first ever purchase on Penon. My experience with Penon customer support was easy and effortless; it made me realized they are very trustworthy. Shout out to Penon for their amazing customer support! Now, for the review.

Packaging & Accessories

The packaging is smaller than I thought. It comes with a small rectangular box. Inside the box is a black case with the IEM, that high-quality cable- I believe is called the S8, and a bunch of tips. Mine came with a freebie IEM because I was one of the early buyers.



The source I used for this review is the Fiio BTR3 and Pixel Dongle. My music source is Spotify premium.

A quick review of the sound difference of both sources
-With Pixel Dongle, vocals are more forward with less space and air than BTR3. Overall soundstage is more 3d-like with the Fiio BTR3; more sense of space and air.



From the first listen, I can tell that the sound is neutral and well-balanced in all frequency.


The first thing I noticed is how clean the bass is. Bass is well defined with highly audible decay on rumbly tracks(I absolutely love it). On some tracks, you can really tell the air and space between bass and midrange; it never bleeds into the mids. It is deep, impactful with good tightness (not the tightest though), and sounds very complete. You can feel how deep the bass on certain songs; in comparison, it is much deeper than my Fiio FH5 and BGVP DM6 v2. The H40 bass is impactful with a little longer decay. What I really like is how huge the bass sounds while maintaining controlled, it is never muddy but very detailed, and the decay is solid and audible which rumbles like a boss. You could really tell the bass sounds truly high quality compared to my other IEMs. The ISN H40 portrays the bass perfectly and deliciously on any songs. It is never lacking and never excessive for my taste; just the perfect amount of high-quality bass.



For midrange, I found it the most enveloping of the sound. The midrange details are very audible, and they show a lot of air and space. The vocals sound complete and silky smooth. Vocals sound big with solid weight. Vocals have bigger weight than my Fiio FH5 and DM6 v2 while maintaining its own space with excellent clarity. Vocals are neutral; depends on the song, it may sound forward yet not shouty but increased in clarity instead. Vocals imagery is mostly in the center; though, it can appear just slightly behind on some songs but still exhibit an excellent sense of space and clarity. The awesome thing about the ISN H40 vocals is the timbre sounding closer to real-life for me; I can hear more tone to it which can reveal more emotions to the voices and when you incorporate it by having a good amount of weight, air, and sense of space- you get orgasmic vocals, lol.



Airy, silky smooth and extended. Details are much more audible than my Fiio FH5 and DM6 v2. I have not yet experienced any sharp and piercing treble (FYI, I have perfect hearing, though I am not trebly sensitive); although, if you know your hearing isn’t in its prime anymore and need to increase the volume up a little more, then maybe you might experience a little sharp treble around, I’m guessing, maybe 8k-10kHz. Now. The treble details may sound big and lively while still retaining its sense of space in the stage; and because of that, the treble detail sounds very delightful. Edit: some people may find the treble a little weighty and relaxed.



Since bass, vocals, and details sound huge while maintaining its respective space with an excellent amount of air- the soundstage may appear huge and large. ISN H40 portrays the soundstage effortlessly and clean. It is amazing how the ISN H40 presents silky-smooth imagery; although, this IEM is not for pinpointing every instrument freak out there. Overall soundstage does not appear cramped; instead, soundstage presents the sound in an immersive or surround sound quality particularly because of the huge sound and good sense of space. Soundstage isn't the tallest, but is wide and deep.



The ISN H40 is horrible. I don’t recommend it.

I’m joking! This IEM is amazing in every way; build design, build quality, amazing cable, amazing sound. The bass, vocals, and details this IEM produce makes my other IEMs sound fuzzy and lifeless. I definitely recommend the ISN H40 to everyone. That’s all I’m going to say because I’m getting tired of this review lol. dfxlbjkedjasds


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I just received my ISN H40 and I must say that my first listening impressions don't really line up with the reviews here.

I tested them with the 4.4mm balanced cable from my Ifi Zen DAC.

To me they sound a bit muddy. The resolution is not how I would have imagined it after reading the reviews here.

Bass is pretty strong.

Soundstage sounds pretty small to me and seperation is not that good.

I tested them with the default green tips over the 4.4mm balanced cable through my Ifi Zen DAC.

Maybe I should try different tips.
@Pascal3366 Although Orb is equally unique and interesting like the H40 in very different ways, I would suggest to avoid it as well.
Update: I replaced the tips with JVC Spiral Dot ear tips and I am using a Hilidac Beam 2S as my source now and they sound absolutely amazing. Good resolution, clarity awesome huge soundstage and fun.


Headphoneus Supremus
Pros: Excellent balancing and refinements in all parts of the sound. Large wider deeper stage for in ears. Solid build with an excellent ISN S8 SPC cable. Crazy value for the cost. Very immersive and detailed sound presentation. Good variety of tips to use. You get 2 earphones if your fast enough to get one early.
Cons: Meager packaging but not a real con, fingerprint magnet on the shells, Will make you think twice about your more expensive in ears you bought that don't sound as good.

I would like to thank Penon for the review sample which was provided for the purpose of review. These are my thoughts about the first IEM from the company ISN.


ISN as far as I knew made aftermarket cables. I own several of their cables the C-16 16 core copper cables, C4 cable and now the S8 which comes with the H40. You might recognize some of these on the nets.


It seems they have decided to dip their toes in the IEM game and out of the gate they have decided to do the tried and true hybrid in a semi custom resin shell. While the technology for the hybrid is not new it does take a good amount of sound know how to tune hybrids to the point of better cohesion and sound balancing. The ISN earphone is just that. Today the market is so filled with hybrids at every cost level I feel the sound quality of yet another hybrid in the market has to stand out. Does the H40 stand out? Let's find out.


The H40 comes to you in a small rectangular box which houses ISNs tried and true zip up rectangular case. Inside the case is the goods. The H40, 8 pair of silicone tips in various sizes and 2 pair of soft foam tips. A large clip to carry the case. This is a decent variety of tips and I am sure you will find something that will fit your ears in the lot. As far as the packaging goes nothing flashy here. To be honest for an almost $200 earphone I was expecting something a bit more substantial packaging wise but hey you don't stuff the packaging in your ears when listening so not a big deal.
DSC06786.JPG ISN H40 retired version with brown cable shown. Retail version with silver S8 cable.

The H40 comes with an outstanding ISN S8 Silver plated single crystal copper 8 core cable in your choice of either single ended or balanced terminations 2.5mm or 4.4mm. You can buy the H40 here or the S8 cables here. The cable itself is one of the better budget aftermarket cables and a good choice when you want to go balance for your favorite earphones. The cable choice matches the sonic qualities of the H40 perfectly so it was a good choice on ISN to choose this particular cable. What is interesting is on the sales page you can choose also what is called a “retired H40” when buying an H40. What is that you ask? Well it happens to be a free early version of the H40. Long story short the ISN folks was not happy with the first version of the H40 so they are now giving them away as a free bee to those who buy a retail version of the H40.

So that means you get 2 versions of the H40. They do only have a limited amount of them so if you plan on giving these a go. Why not get another version of the H40 and the cable it comes with for free. Now onto the review

The H40 build wise is very familiar to me. It is made of resin in a semi custom conch shell shaped solid piece of plastic. Inside houses a single 9.2mm dynamic for bass with 3 BAs. One BA for the mids and 1 composite dual BA for treble duties. All housed in a black onyx shell with a gold colored nozzle. The look is clean and the universal shell design means. These will fit most ears with good snug comfort and isolation. Due to venting of the bass the isolation itself is only average here but makes up for it in the way of the sonic ability of the H40.


Sound wise. Wow where to start. The overall sound balancing has a good fundamental balanced Frequency with something what I call an IT factor. Yes ladies and gents. These have “IT”. Even on open listen I realized I was dealing with a sound quality that I was not expecting out of the box. Having listened to 100s of earphones in just about all price ranges. I have a certain expectation of sound quality at the given price point. The H40 my friends don't sound anything like your $200 earphone. It sounds more closer to what you hear from flagship earphones from much more established manufacturers. To hear this type of sound quality come from a first time effort. My mind was officially blown!

The H40 is one of the most complete full blown high quality sounds I have heard for in ears that incorporates excellent balancing, great imaging, airy extended detailed treble with a full blown punchy bass that rumbles your ear off when called for. All in a roomy spacious large deep sound. It does have a surround sound type of quality to the tuning that just immerses your hearing. It is hard to listen to these critically as you get so lost in your tunes you forget your trying to analyse the tuning. It is a good problem to have.

The treble end incorporates a silky smooth extended shimmery and slightly airy quality to it that is not too common in this price range. It is the type of treble I heard on my Ibasso It04 and more closer to the Sony Z5 both of which cost more than double the price of these. But then it doesn't stop there. The mids, the lush and rich full on mid range.

Mids have a fullness and depth that has a SQ unto its own. Vocals be it male or female sounds stupendous. Slightly forward sounding yet the mids range is astounding in how it focuses the sound to your ears. It sounds like I am surrounded by the mids with excellent detailed imagery and that is the most enveloping aspect of the mids. It is so good on the H40 it is now my bench mark for hybrids. Folks you don't get mids like this until you are willing to spend much much more. The mids on the H40 can hang with the mids on my Andromeda S easily.

Then you incorporate a crazy bass end with the truest meaning of dynamism. Bass is outstanding here. This is no gimpy neutral bass we are talking about here. It has a good amount of healthy high quality bass. It is the type of bass your mom warned you about. Quality in the punchiness and a low reaching rumble in the region. Bass has a roundness to it again that is not too common in the price range. Bass has excellent control and comes to play when there is bass emphasis in the tune. It will and does make your rump shake, prat is off the charts good on these. It does justice to orchestral tracks as well as your favorite hip hop tracks. Don’t mistake this punchiness to something sloppy for the sake of beef. Not on the H40 folks. It has emphasis but don’t step out of bounds. It goes toe to toe with any high end bass I have heard and that again is a testament to how excellent the tuning is in all regions of sound on the H40

The H40 actually maximizes tuning of each driver to full potential then you incorporate a larger than average sound stage width with excellent depth and what you get? One of the best in ears I have heard easily this year at any price.

This earphone is the only earphone I will gladly give 5 stars to this year as it deserves it. I honestly feel these have to be a bench mark meaning it has to be one of the best if not the best you can possibly get for the price range and for a small company like ISN to pull this feat out of nowhere? Remarkable absolutely Stunning achievement.. Bravo. As a part time reviewer it is earphones like this from a small upstart companies that drives this hobby of ours. It is earphones like the H40 that will put a statement to much more established companies and they should take note. This is now the new type of sound you can get at the price point. Don’t mistake this with your garden variety decent hybrid. This is a statement piece if there ever was one.

The H40 is no joke my friends. It is serious about sound quality and for that I give it the highest rating I can possibly give. To say I was a little impressed with the H40 is an understatement. It is one of those earphones that again has that IT factor. In earphonedom there is so much you can choose from now a days. Why choose an ok or a good phone. How about a phone that will blow your mind. That my friends is the H40..Thanks again for reading and as always happy listening.
Is there a UK dealer?
@Dsnuts thanks for the review. How do you think the H40 compares with the Aladdin?
ALaddin is more neutral harmoinish tuning. H40 has a bit more coloration to its tuning meaning it will have bigger mid bass vs more sub bass focused Aladdin bass performance, mids will be slightly more forward a bit warmer in tone vs Aladdins smoother more neutral tonality. Both have excellent presentations in what they do but both are different in they way they approach sound tuning. H40 has a bit wider stage otherwise both are excellent for music listening.