Headphoneus Supremus
Lush basshead pleasure
Pros: -well balanced basshead tonality
-warm but not too dark
-good note weight
-natural timbre
-smooth lush vocal with no sibilance or killing pinna gain
-wide soundstage
-deep thick sustain rumble
-thick and immersive musicality
-excellent accessories that raise package value
Cons: -bass bleed and warmed mid bass separation
-average technicalities
-average imaging
-dark mids
-rolled off treble (no sparkle-decay-snap)
-not very competitively priced

TONALITY: 8.2/10


ISN is a sister brand from Penon Audio and try to offer high sound value IEM in different price range.
While they mostly specialize in hybrid, like the bass heavy ISN H40 which is 1DD+3BA, today I will review their single dynamic driver model: the D10.
Priced 150$, the D10 use a 9mm dynamic driver, it isn't stated what type of diaphragm or magnet it use, but we can expect similar DD model find in the H40.
This is my third ISN product I will review, and the most entry level one so let see if sound value is there with this one too!



Nothing to complaint construction wise, the D10 being very similar to both H30 and H40 in that regard. It's thick medical grade resin plastic that feel sturdy and is smooth for the skin. The organic shape permit secure and comfortable fit. Housing is light. Mmcx connector feel solidly embeded in housing.


The cable included is marvellous. Its the ISN S4, priced 60$ on Penon store here:
Its a 4 strands 64cores OCC silver plated cable of very high quality, smooth, flexible and light. It doesn't have ear hook which is a plus for me but perhaps not for everyone. Connectors are solid and their no sound deterioration, dynamic taming or euphonic warmth added to the sound, which is proof of a good cable.

As always with ISN (or Penon IEM) we are spoil with good quality accessories. Their plenty of siliecone eartips choices (3modelsx3pairs each). Carrying case isn't the cheap basic one we often get with chifi IEM, it's an elegant magnetic false leather carrying case. Very nice.


Guilty pleasure anybody?
If you are an intense audiophile use to entering ''critical listening mode'' in a pathological way, yes, the D10 will seem underwhelming in resolution and even in technical performance like attack speed and control, imaging capacity and transparency.

Yet, if your very sensitive to the timbre naturalness and tend to prefer thicker, more natural one that doesn't have boosted grain brightness, or anemic body, you will suddenly find the D10 very appealing in that regard.

But most of all, if you love BASS quantity and roundness, as well as well felt dynamic with good note weight, you will sure tend to love the D10 at first listen and perhaps even become addicted to them like I am right now.

The ISN D10 are all about laid back bassy fun with smooth non fatiguing treble and dense lush mid range that is all but bright, thin or overly boosted in upper mids. Fan of big warm weel define slam with vibrant sub bass will love those, as well as fan of male vocal or low harmonic instrument like cello that benefit warm grunt of deep boosted bass.

We can call the tonality as thick warm V shape with dark upper treble and fowards lush mids.

These are near all about bass slam and chunky rumble, so expect the D10 to feel unbalanced in that regards if you seek for neutrality or crisp W shape tuning, but quite cohesive and balanced if your a legit basshead.
Low and mid range act hand in hand here, in a warm way, yet it doesn't go plain muddy or messy and tend to mix sound layers in a rather spacious way so the mid range is darken in resolution and not very generous in micro details or air, but have very pleasant timbre and great sens of musicality, laid back one.
While for the bass it's all but laid back! It pack a big chunky juicy slam that will let nobody indifferent and induce intense headbanging. While we sure have more quantity and quality, it isn't a thin or overly resonant boom that the D10 deliver but a lively, vibrant punch that find the sweet spot between mid and sub bass boost, in that regard it's similar to the pricier H40.
The transition in lower mids is thick and not cleanest in separation, as well the kick is warmed-thicken by rumble, but in a smoothly layered way that will benefit male vocal, which are fully bodied and fowardly extracted with the D10.
Nonetheless, sub bass line are well articulate and layered enough, this is another part of D10 addictive magic, which proof the dynamic driver used is fast enough and flexible in transient response. Imaging thick thump or oomph sticked on sub line or rumble, and you get an idea of how bassylicious D10 can be. As well, expect the D10 to add extra low harmonic boost to near all instrument, so while for cello or contrabass it can be a benefit, it would not be for piano or violin which would be compromise in higher pitch rendering.

Now, I guess some people would find the mid range underwhelming and we can say the same for treble, but while the latter is problematic, mid range please my ears musicaly. Its warm but not too recessed, it's thick but not too muddy, it's not edgy but doesn't lack dynamic.
This is mids colored with low harmonic thickness, those are mids that will add sens of breathyness to female vocal and fully extract and boost male vocal presence and body without using magnify presence trick. Those are one of few IEM that make me listen to Johnny Cash without feeling he's super distant, thin and grainy souding (poor recording quality). I rediscover male singer with the D10.
And for female singer it's very lush and smooth, in fact, it make Arianna Savall high pitch soprano singing fatigue free, since this singer tend to suddenly pierce my ears with pinna gain loudness or sibilance, her its organic, creamy and very polished, the texture zone is quite tamed with D10 and this is a blessing for those that favor timbre and color of vocal over ''image of presence'' that lack soul and body like near all harman tuned IEM.
But this come with a trade off in resolution which is darkish, lack details and well, presence definition. For ex, the piano note will feel...coming out of a woodwind instrument but with sens of note weight, in the sens that note stroke and tone is there, but you can't ''see'' the finger pressing the keyboard, nor the decay of the note flowing in they air.
Same goes for the violin, but in a less problematic way unless the playing is very fast, it will lack bite, texture and natural resonance amplitude, which is plenty for the cello as said.
Fans of vocals, woodwinds instrument like saxophone as well as upper mids sensitive and lush timbre lover will be please by D10, but those seeking crisp mids and transparent layering that permit proper imaging accuracy will feel underwhelmed.

And this treble....hardest part of the sound to describe since it's quite understated with just minimal spice to avoid complete darkness. Let's begin by saying cymbals crash is very tamed and if your goal is to be able to pin point all percussions in complex jazz or rock track, the D10 is certainly not the answer. Does this mean acoustic guitar sound bad? No, but harp sound like acoustic guitar their something going on here with high pitch tone rightness. Its dark creamy treble that doesn't add air, nor sparkle, which in fact is lacking. Percussions are a bit foggy too, making it hard to extract them in soundscape, even snare is softed a bit, so this isn't vivid treble at all....not alot to write about sound impressions here apart making up details I don't really hear. These aren't for treble head nore high resolution seeker. But this doesn't mean the D10 sound underwhelming, just laid back and very smooth in highs.

Soundstage si quite wide and quite OK in tallness, but their no depth to it.

Imaging is dark, layering is mostly about sub bass going above the mids and treble in term of dynamic articulation, instrument separation is fogged by bass resonance when it occur and not very clean when their no bass due to lack of definition edge. So, poor imaging here.



VS SuperTFZ Force 1 (1DD-80$)

The Force1 is a radical basshead IEM too, but take a polar opposite direction by offering brighter and even more hard hitting drastic V shape with a more excited and speedy dynamic heft.
Bass is faster but thinner and more resonance, rumble is more about air than chunky vibrant body of D10 and lower mids are more scooped so male vocal doesnt sound as bodied and fowards, they have brighter presence and thinner body. Force1 bass is faster and more thumpy, less warm and bleedy.
Mids are brighter, thinner, better resolve but feel more recessed and harsh, texture is more grainy-fuzzy too and sibilance notably more present, yet it feel a bit more open too.
Treble is notably more boosted and agressive, deliver higher amount of details, its more airy and snappy too, pinna gain is louder and overal highs can create more fatigue than smoother darker D10.
SOundstage wise, Force1 is wider and deeper. Imaging is superior too, more transparent in layering and wider and more accurate in instrument separation.

All in all, i prefer more laid back and natural sounding tonality of D10, but technical performance are superior with the Force1 basshead way. If your a basshead that need full sounding vocal, avoid the Force1. If your a basshead that need boosted treble, D10 will be too dark for you.

VS ISN H40 (1DD+3BA-195$ (or 155$ with my secret coupon code))

Those 2 are name exact same in tonal balance which doesn't mean they sound the same since H40 is notably superior in technical performance, so we feel its a bit sharper W shape instead of warm V shape.
Bass have better separation but similar sub domination impact, yet its less warm and thick as a whole and punch definition is better resolve. Mids are clearer and just a hint brighter, they are more dynamic and detailed and have better layering that permit them to be stick on bass shelf instead of mixing up with it like the D10. While hint less fowards, vocal are wider in warm presence as well a hint thicker and more natural in timbre with the D10. Treble is faster, snappier and more energic in attack yet similar in upper mids softness with H40, we struggle less to find percussions and have slightly more micro details, it's less blunted in attack and dark-thick in macro resolution.
Soundstage is similar in wideness, hint less tall and hint deeper cleaner. Imaging and layering is superior too with H40, though not class leading at all.
All in all, it's hard to justify D10 existence when we can get H40 for 45$ more (or 15$ with my secret coupon code), but timbre and tone is a bit more natural, this is due to lack of BA flavor surely. Anyway, I prefer less dark tonality of H40 which is as bassier, but would like the chunky sub vibrance of D10 thing certain, technical performance are notably superior with H40.


The ISN D10 might not be very competitive in term of technical performance, but this is inherent to the tonal balance aimed which is all about warm basshead fun with smooth natural mids.
If your all about treble, D10 is certainly not a wise choice, but if your all about big bass and thick lush timbre, this might become a very addictive IEM like it is for me. But bass and even mid range lover might find these higly addictive.
Guilty pleasure? Sure, but very colorfull and even well balanced for the musical experience aimed. These doesn't create fatigue yet engage you in a very rumbly ride.
Fan of Soul, R&B, rap and big beat that doesn't need fast snappy punch, the D10 will sure bring a smile to your face like it does to me.

PS: I want to thanks Penon for sending me these IEM when I share them my envy to test more bass heavy earphones. I'm not officialy affiliated to this audio distributor and my opinion are 100% unbiased and wildly free of any influence.

You can order the D10 for 150$ here:


Headphoneus Supremus
The ISN D10
Pros: 9mm full-range DD
The S4 cable, a $58.90 dollar value by itself
Incredible build, offering sound occlusion and comfort
Great soundstage, bigger than you could ever guess
Well executed single DD design, one of the best I have heard
Sub-bass, can you say sub-bass?
Semi-custom form-factor
Giant fully-filled omnipresence
Realistic instrumentation placement into soundstage
Cons: NOT


The D10 is another great release from ISN. The ISN company channeled the abilities of this full-range 9mm DD into a new release. ISN is doing a balancing-act, by milking every last ounce of sound from this little driver. After spending many weeks listening to the D10, the uniqueness and completeness became more noticeable. You realize it was a necessity to join the D10 with the included $58.90 ISN S4 cable. The ISN S4 allows a kind of clarity to lift the D10 higher in both tone and technicalities. Such "pixy-dust" helped tune the low-end section and bring about pace, squishing any lower fog before it started. So today is a special review day! We will put the D10 against 5 other IEMs of lesser and greater cost! Our find the true objective value, to learn if the ISN D10 is worth the $149.00 asking price. But beyond that, to discover the qualities regardless of remember it doesn't matter what it costs.........if you don't like it. And if you do like's priceless anyway.

head-fi 4.jpeg

Comparisons to 5 other IEMs:
The additional differences on the surface takes place in size reference between models. You can really judge the size difference between the lower left ECCI YST-02 and the lower right Seek Real Audio Airship. Though nozzle length is a little more tricky to judge due to the whole IEM body acting to get the nozzle closer in fit. Though it may still be obvious that both the Purple Reecho OVA SG-01 and the Airship have the shortest nozzles? In my uses they all fit nice though some slightly better than others. Though it does make you wonder if the Airship will fit everyone? A lot of the times finding an extra long ear-tip will allow better fit with a shorter nozzle IEM, by essentially creating a longer nozzle with the length of the bore itself. For me it's super hard to imagine that just a few short years ago (2018) there were very few semi-custom IEMs, now it seems everyone has a variation of the semi-custom form-factor. Such results mean better fit and better sound due to better fit. The other coincidence is every IEM, all 6 IEMs being evaluated today have good nozzle tip rings, which act as an extra lip to ensure tip placement. Finding a secure tip means that there is less variation in movement, hence a more stable fit with the tip held in place.

Left to right
Left to right

1) BQEYZ Topaz, Piezoelectric, 1DD, $89.00

2) KB EAR LARK, 1BA, 1DD, $29.99

3) Reecho OVA SG-01, 1DD, $49.00

4) ECCI YST-02 1BA, 1DD, $75.00

5) The Seek Real Audio Airship, 1DD, $179.00

The choices used:
Some may question my choice of challengers. And……I would a point, price doesn’t matter. It does matter, but what matters more is if you relate with whatever sound signature the IEM has. It’s about emotion and those feelings you get when you interact with the music. Such abilities are spread out over a wide range of price brackets. Also these were chosen as I truly like the ear-phones, so what better test is there? The fact that I’m intimately close to them, also if you look close each of the examples have DDs. Two with BA add-ons, one with a Piezoelectric tweeter, and 2 with single full-range DDs, to be direct comparisons. I’ve also used the same ear-tips and 4.4mm cable style to give extra fairness. The same source was used to, finding the Walkman WM1A to be a well rounded. If I have given an advantage, I will disclose that I found the tips I’m using and DAP I’m using to make the ISN D10 sound the best. So in a slight way I found what works with the ISN D10 and made every other IEM follow accordingly. Is such a performance handicap fair? Well, I have to use the same ear-tips, and I have to use the same DAP……so making them fit the D10 is a little of a head start, though remember the other IEMs tested may benefit from the same set-up. Also this emulates maybe someone with only one set of favorite ear-tips and one favorite DAP. The main issue here is I don’t have a volume measurement device. It’s been said many times before that various volumes can and will effect the perception of sound quality. Still this has worked out (in the past) where I have guessed to equalize volume levels. Mainly we are looking for the sound reproduction abilities in timbre, tonal response (is it even and correct), we are looking into how the bass works. There are subjective ideas of bass response........such as character, delineation, focus, speed, and realism, and the ability of leaving the midrange alone. Taken into account the overall balance of treble to bass finding a working musicality due to emphasis in correct amounts. In all fairness the ISN S8 Hybrid cable was used in 4.4mm was used for all competitors, though the included S4 cable was used for the D10, due it being the included cable and the fact that it was the only MMCX cable used in the comparisons. It’s known that the ISN S4 is an advanced cable which beats out the S8 both in cost and thickness. Yet with this test, being every competitor used the ISN S8, it would lead to a level of fairness.

1) BQEYZ Topaz, Piezoelectric, 1DD, $89.00
In direct comparisons we find the BQEYZ Topaz having many of the same attributes, though where the D10 pulls away is in the treble of all places. You see the Topaz has a unique treble in that it’s a piezoelectric 9 layer composite stacked right on-top of the dynamic. Such mixtures do offer a nice separation of upper treble, except it’s off timbre and way extended. It’s hard for me to believe that such a treble is actually there in the song, as 1) it’s thinly pushed-up in frequency and 2) actually a separated place existing in the treble soundstage, too far out, though the positioning does offer entertainment, it’s simply not natural. While defiantly fun and an incredible bang-for-the-buck, I would choose the D-10 for bringing a more cohesive and complete treble experience. While slightly less bright, it’s more cohesive and shows more detail in that the treble elements are more evenly arranged to become more of a reflection of life. Also it should be noted the D10 was way more efficient.

2) KB EAR LARK, 1BA, 1DD, $29.99
I dearly love this IEM. This was the first to show me that the market for this price-range was truly changing. And while maybe every example of the Lark may or may not be the same due to QC, the first run a a brighter treble with the second “correct” batch resulting is a smoother, more welcoming sound. I have to say, this ISN S8 cable is a great addition to complete the sound, actually taking the sound response into a more mature and detailed direction. The first thing that gets noticed the similarity to the BQEYZ Topaz, in that there was a complete separation of treble from the lower frequencies. Normally I prefer such contrasts but our LARK while offering a slightly brighter treble, is showing a slight issue again where the treble 1) Doesn’t blend as good, and 2) has an air of plastic sounding instruments, in contrast to the D10’s natural and complete cohesiveness and togetherness. It should be noted, again the ISN D10 turned out easier to drive.

3) Reecho OVA SG-01, 1DD, $49.00
This was the hardest to compare test so far. Both single full-range DDs that are well tuned and take care of business! The first clue that we were entering a battle was Reecho has the same response to volume as the D10. While bass actually seemed comparable, there was an added relief which took place to make the D10 nudge ahead. Such detail was in a way unexpected to be found. Though I will say the Reecho was fully grooving to the whole combo of S8 cable making it brighter, as well as the midcentric response with use with the Sony Walkman WM1A. Literally I can’t think of a better combo of cable and source to lift the Reecho up into focus! The Reecho also expressed a different groove in that there was a more musical lower midrange that made you wonder what the D10 was not doing to get groove down low? The Reecho sounded way, way better than expected? Still it was not in the lower midrange or bass department but the treble and upper midrange where the D10 really put the screws to the Reecho, showing a better level of overall competence, and detail.

Is this a $100 price difference is sound? They really are different in that the D10 is more traditional in shape, where the Reecho is kinda strange but still fits great. The D10 is lower weight as well as more comfortable to wear. Also remember, the D10 comes with a way better cable that laughingly is $58.90……more than the total cost of the Reecho itself! So, there is that. The Reecho is a better value if you were just centering on the price, but in regards to all the perimeters the D10 is a better IEM. Also it should be noted that the ISN S8 cable used to get the Reecho here is $32.50, adding to the overall cost of the Reecho. Better sound with the D10 at basically double the S8/OVA SG-01 price. $81.50 the Reecho OVA SG-01 with ISN S8 cable comparable to the ISN D10 at $149.00 already with the $58.90 ISN S4 cable. So while the Reecho was amazingly close, it took a while and some revealing music to truly show what’s up. Only $67.50 more than the tested Reecho OVA SG-01 with the ISN S8 cable gets you the ISN D10! Also you have to take into account the source, being the Reecho will need the expanded treble and forward midrange to gain such resolution, same as the D10 being inherently dependent on the WM1A for sound quality, as it is always the sum of everything used to get the end-sound.

4) ECCI YST-02 1BA, 1DD, $75.00
This is a cool set-up. One one the main curiosities here is that the YST-02 is somewhat famous. Famous for offering a more coherent tune than it’s more expensive younger brother, the ECCI YST-03. Even priced at $105.00 and sporting 2 balanced armatures; one balanced armature more, didn’t guarantee quality. Why? Well part of it maybe a better tune, but it this case even the YST-02 technical aspects could be viewed as possibly better in contrast to the slightly more expensive ECCI YST-03? Also it must be noted that while the YST-03 doesn't need the ISN S8 cable due to the YST-03 already being too bright, the older brother YST-02 could actually benefit by using such a cable. In many ways the included cable with the YST-02 and ISN S8 are parallel cables, though the ISN S8 cable is better and the perfect match for out YST-02 today! Nowhere did I come to a revelation of sorts until I tried the YST-02. Truly even though it’s half the price of the D10, I still wanted to verify for folks where you hard earned dollars are going. Also this was the first IEM in my tests where the wide-bore tips needed to be changed out for medium-bore. The ISN S8 cable really boosted the upper-midrange and treble here. While with the medium-bore tips if was pretty much dialed in, still there was a truth to be found. Testing back-to-back enabled a kind of easy going listenability to the D10, only in contrast to the ECCI YST-02 would such values be obviously noted. While in testing for the YST-02 for review it was shown that the BA the YST-02 uses is kind of a top-off of sorts, getting a smidge extra upper relief and imaging for the primarily full-range DD the ECCI YST-02 uses. Still the difference here was a D10 buttery smoothness that seemed to take over. Gone was any steeliness or metallic tinge so very much at risk of hearing with the ECCI YST-02. Replaced with a kind of accessibility that made owning the D10 simply better and practical. Imagine using the word practical as a sound descriptive, but for once here is this test, it applies! A wanting of a still detailed yet fluidly-warmer response, that is what the D10 does! But beyond that it’s the great note weight that propels the music to simply be more real and consumable? The notes are bigger, rounder, have better decay and are simply more pleasant. This is actually a surprising test, as I thought the YST-02 would put up more of a fight. Yet the D10 had obvious superiority which it showed right out of the gate. Because I listen to so many IEMs it sometimes takes a direct comparison (even for me) to end with my correct barring. While maybe a different DAP, or cable could help the YST-02 become more enjoyable, the metallic tinge I heard doesn’t go away. That is a permanent character, sometimes heard more and at times heard less. Here especially were electric guitars where the tone was overly bright and in high contrast to the rest of the instrumentation with the YST-02. Where the D10 had an uncanny approach of both naturalness and realness, that it effortlessly arrived at. It should be noted that the YST-02 was also ridiculously difficult to drive in comparison to the ISN D10. Probably the YST-02 was the one IEM that suffered from the worst synergy in out test today. It seems there will always be one that doesn't get the correct extras such as DAP choice, or ear-tip choice. I reviewed the YST-02 and the Reecho OVA SG-01 at about the same time earlier this year, and by all accounts they seemed very close in many ways, where today (in this synergy grouping) the Reecho is by far showing meaningful blending with the equipment on hand. In fact the Reecho has a bounce and groove thing that is almost superior to any IEM being tested. The Reecho has kind-of a pace thing that makes the music even better? While it doesn't have all the details of some IEMs in this test, it has a special quality that almost makes those details secondary. Though the real reason the ISN D10 wins out over both the Reecho and YST-02 is because it's placed right in the middle, meaning it has the lower treble extension closer to the YST-02, except it's non-metallic, then it has the warmth of the Reecho. Thus the D10 takes the win, with a combination of upper detail (like the YST-02) and the nice warmth of the Reecho.

5) The Seek Real Airship, 1DD, $179.00
Finally we come to our final match. A single full-range DD priced a slight bit more money. In finding the Airship it should also be noted that it’s newer, representing a possible foot-forward in ear-monitor technology. It needs to be expressed that maybe this battle between the two is the most even. Similarly priced, similar technology and both offering a basket of goodies for the price. Also past experience has shown that the Walkman WM1A and ISN S8 cable to be a match made-in-heaven for the Airship. This is important as such a cable and wide-bore ear-tips act as an EQ to brighten-up the Airship's response.

It should be noted that both IEMs have over 200 hours of burn-in. Such extremes in use follow suite to guarantee no missteps or hazards to be found in testing. Both drivers show a smoothness upon reaching such intensive burn-in, though most smoothness happened in the first 75 hours. Single DDs need more also due to it being a single sound source, so better the burn-in to be more noticed, being it’s only one driver in use. The D10 takes the lead. While the Seek Real Airship is slightly more reserved in stance, the D10 is bigger sounding. It really depends what you are looking for as the Airship offers shorter nozzles, but amazingly my wide-bore tips fit great, though just getting fit. The Airship is slightly more together in response meaning it’s slightly more tidy in sound. Where the bass bump is more controlled and sculpted, it is very much preference here. Two single DDs battling in out and finding a very well-matched fight. Where some may actually prefer the more demure response of the Airship, it was more polished and reserved, where the D10 was just bigger and more alive, offering vibrancy and imaging further out...........out-side of your head. Both have incredible note weight and decay, both offer a vacation from steely BA timbre………as there is none with both models. Truly I guess I love both equally? The issue here is the Airship included cable. That’s the kicker, being the Airship is slightly more money to begin with, then you need an aftermarket cable to access 4.4mm amplification and take advantage of the added Hybrid cable designs. So ISN D10 at $149.00 complete or the S8 cable for $32.50 and the $179.00 Airship cost? Truly this is a tie, personal preference being the determining factor. Do you want slightly bigger but less controlled sound of the D10, or the more calculated and closer your side style of Airship response? Normally I go for the more vibrant ways of IEMs adding to the fun factor, but at the same time the sophisticated charms of the Airship are undoubtedly special and alluring?

The ISN Company:
ISN current cable offerings
Silver-Plated IEM Cables: S4, S8, AG8, S16 and one Type-C Silver Plated USB Cable
Copper IEM Cables: C4, CU4, C16
Mixed Cables IEM Cables: Solar, G4, GS4, SC4, H8, H16
Gold-Plated IEM Cables: GC4, GD4
Pure-Silver IEM Cables: AG8

ISN Ear-buds:
Rambo 2

H50 10mm Composite DD (bass) 2 BA (mids) 2 BA (highs) $295.00
H40 9.2 DD (bass) 1 custom BA (mids) 1 composite 2BA (highs) $195.00
D02 10mm DD $79.00
D10 9mm DD $169.00
EST50 1 Knowles BA (highs), 1 Sonion BA (mids), 10mm DD (bass), 2 Sonion ESTs (ultra-highs) $459.00

Strangely, even-though making all this complicated stuff, ISN describe themselves only with one sentence.

“We are a wire production and R&D factory.”

What interesting is ISN makes 5 IEMs and they scale completely to different price brackets. While the $169.00 D10 is second to the bottom is price, it still offers a dramatic and involving sound signature. Starting with only a 9mm dynamic driver, it’s all about utilizing everything a single dynamic driver is capable of. Because ISN is a cable company first and foremost, they utilized their skill to find the perfect cable for the D10. But in addition to the cable, they worked out the little things, like how the custom-form-factor fits, and the look and feel of the IEM. In fact just holding the D10 in your hands is an experience. The completely resin build is actually seamless. What that means is they took care to achieve this kind of ergonomic which elevates the D10 to even a more valuable place. The feel in your ear, the fit and placement achieved through the design. You get the message that they know what they are doing! That's even before you turn anything on. Such semi-custom form-factor enables extra noise occlusion due to how close the D10 fits inside you ear. Because of its low weight, another set of dynamics enable comfort and usability. Due to getting the $58.90 ISN S4 in 4.4mm, it comes without ear-hooks, though the 3.5mm and 2.5mm cables do have them. Still fit was fine and better than fine. The nozzles are actually semi-long which means if you have had you run-ins with too short of nozzle length, here you can rest assured you will not have any issues.


The box opening experience gets you everything you need. 9 full sets of ear-tips to try, a shirt-clip and cleaning tool. The actual carrying case was not given with my D10 ear-phone, though I included an approximation in the photograph. Of course as mentioned earlier, it includes the necessary S4 cable in your choice of 4.4mm balanced, 3.5mm single-ended or 2.5 balanced. It comes in a beautiful metallic blue box with foam inserts to protect the IEMs.




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ISN Audio D10 Dynamic Driver MMCX HiFi Audiophile In-Ear Monitor IEMs (Purple-black)


ISN D10, 9mm Dynamic drivers earphone.
Equipped with our very own ISN S4 cable. MMCX connector design, Improve the playability.
Earphone housing is resin.

Sound signature:
Crystal clear sound with defined low frequency that dives well.

Middle frequency full of clarity & sparkly high frequency.

Brand:ISN Audio
Model: D10
Driver: 9mm Dynamic driver
Material : resin
Impedance : 16 Ω @1khz
Sensitivity : 100 ± 3dB @1khz
Frequency response : 20-20kHz
Connector: MMCX
Plug: 3.5mm Audio/2.5mm/4.4mm Balanced
Cable length: 1.2M

ISN D10 earphone
8 pairs of silicone ear-tips
Carry case
Clean brush

The S4 Cable, priced at $58.90

ISN Audio S4 4 Strands 63 Cores OCC Sliver-plated HiFi Earphone IEM Cable
4.4mm cable and MMCX connector cable do not have plastic ear-hook


Brand: ISN Audio
Model: S4
Material: Single Crystal Copper Sliver-plated
Number of cores: 4 strands, single strand is 63 cores, a total of 252 cores
Connector: MMCX/2pin 0.78mm
Plug: 3.5mm audio/2.5mm balanced/4.4mm balanced gold-plug
Cable length: 1.2M

Built-in 500D tensile fiber,superthick conductor, it is 3 times the conductor usage of the ordinary upgrade cable.

Less electric resistance, the sound is clearer and more uniform.

The silver-plated cable has good electrical conductivity, as well as a bright and lustrous surface, and the silver has high corrosion resistance, which can effectively change the sound fied.

The three-frequency positioning is more accurate, more transparent creating a better sound experience.



What if I told you the bass was not cut-short, but the upper-end treble was..........would you believe me? It's not that the upper-treble and mid-treble are completely missing, but there is a lower treble emphasis. I'll be darned.......this works for me, and may work for you? This IEM was not supposed to be one I truly liked, but in the end I did. It goes against all I can try to understand on paper. But it works, not only does it work, it works fabulously. Probably the extra distance that lower treble items are fully forced into, when they fall to the outskirts of the soundstage? The subtle smoothness that is omnipresent and potent even though it's not flashy or in your face. And it's not a question of these just barely getting by with the treble, no this is a full-on attribute and something to cherish and come back to! There is nothing half-way about this treble, even though on-paper you could guess different. Again it's the imaging that saves the day, because it's so good. And while you know that there may be an inkling of more treble out there (with other IEMs), you don't feel short-changed in the least. If anything this smoothness enables all night listening sessions and a style of intimacy you would have to hear to believe.

Surprising the mids are really not that behind at all. There ends with a kind of focus on the mids due to the treble only being totally prominent in the lower treble. Such balance totally works here as a way to go. And while vocals are exquisitely placed, finding not exactly a forwardness, but not a behind either. Where things really get good is due to the exotic smoothness always present, always. Such glossed and waxed embellishments could make someone think twice before ever wanting anything else. Such a display is full-frequency and not boring in the slightest. Offering a kind of distinct personality, while still doing any genre with well accepted competence. Imaging (while slightly less bright in over-all tone) somehow ends genuinely analogue? I don't know what else to call it, but people who already have the D10 understand what I mean. A forgiving warmth permeates the D10, asking nothing in return except your enjoyment. In this ISN world guitars get (somehow) an extra dose of crunchiness at the same time sounding slightly understated........again analogue. It's the D10 serpentine groove that really takes the cake though, a wonderful pace as this whole thing is interconnected, because of a careful balance.

The first thing that hits you is just how smooth and complete the bass is. When I think ISN I normally think bass. The bass is definitely prevalent and noticeable but gives up to a genuine pace and rhythm that other IEMs fail at. In the price bracket in which the D10 lives, it's one of the very best bass options out there. Later in the music section I can give better detailed examples of it's character, but probably the greatest quality is how the bass rides underneath giving ample space for the midrange and treble elements to kind-of float on-top. Not only does it give support in the lows, but it's organized to give the perfect top-end balance to the treble, leaving all the room needed for midrange and treble flourishes to be expressively heard. But within that exact balance the bass nurtures the extra musical elements. While thin recordings are not magically brought to life, better recordings go "full-tilt" to bring the musical involvement .......and they do. It's strange but these IEMs definitely go the full mile to display the file quality of whatever you're listening to. Get them a great recording and witness the agility and bass focus that takes place. There is a special bump that is connected to pace that just works. The nice round thumps are intertwined to bring the music together the way only the bass can do. It's the cohesiveness that brings about a straight-up listenability that's by far greater than the price asked. Such extras give movement to Rock but also go to the outer reaches of the stage during classical to simply make your music big and involving. What happened was a surprise when I went to OSTs that had extended sub-bass, I had no true idea this particular IEM was even remotely capable of doing this level of replay. Literally every last (lower) frequency present is displayed, now I understand when they call the D10 a bass monster.


Hans Zimmer and Junkie XL
Batman v Superman OST
Is She with You?

96 kHz - 24 bit

At 3 minutes 44 seconds the sub-bass hits. It's a rolling affair and slowly progresses till 4 minutes 41 seconds, where it does a send-off. Truly this is amazing sub-bass, and many times more than I ever expected from the D10. The fact that I had to find it music to chew-on.

Their War Here:
Ha, if this isn't the best song on the OST. The timpani hits at 1 minute 10 seconds, then the deep-deep toned strings at 1 minute 28 seconds. Gosh, I almost am feeling the floor move, this is great. More drums and a whole orchestra going along for the ride. I could list every song on this OST........the blasts at 2 minutes 54 seconds and continuing the 3 minute mark.............

ISN offers a wide range of different IEMs. ISN have made a huge selection of noteworthy cables and generated a fan-base with their understanding of cable metallurgy. The next chapter was to start to introduce value IEMs which would go up against brands costing 2X or 3X the money. The D40 was an incredible hit, as it should be for the sound-per-dollar spent. The H50 is one of my personal favorites of all time, just a great understanding of how to make a midrange IEM sound. The D10 continues to further the goals of sound value at an affordable price. To tell you the truth, I was skeptical as to the outcome of the test today, reason being is you don’t know till you know. Such side-by-side tests are critical in the understanding of product value, regardless of preference.

The D10 sound is comfortable, as is the fit and cable texture. The weight and nozzle length are perfect. The build quality is to die for. You’re buying from a fairly new builder, yet they have a profound reputation for supplying quality and good sound. The ISN sound is about quality bass, yet the bass is in no way overboard, in fact notice the side-by-sides were more about treble quality wining-out with the D10. Where it’s a V shape response, still it’s done in such a subtle way as to give full respect to other frequencies. The bass and treble are not that drastic as to cloud your enjoyment, in fact the whole signature is about the middle-range imaging and authority. With that said the ISN walks a fairly even line offering a big soundstage, a soundstage bigger than the more expensive Airship. If you think the ISN D10 is for you there is no more information I can come-up with to give a clearer picture. Just take a chance on it…….you’ll be glad you did!

Get them here for just $149.00

These thoughts and ideas are of one individual, your results may vary.

I would like to thank Penon Audio for auditioning the ISN D10 IEM.

Equipment Used:

Sony WM1Z Walkman DAP MrWalkman Firmware 4.4mm
Sony WM1A Walkman DAP MrWalkman Firmware 4.4mm
Sony TA-ZH1ES DAC/AMP Firmware 1.03
Electra Glide Audio Reference Glide-Reference Standard "Fatboy" Power Cord
Sony Walkman Cradle BCR-NWH10
AudioQuest Carbon USB
UA3 Dongle DAC/Amplifier 4.4m

Behold, ISN now gives you the premium case with your purchase. This fact I was unaware of when doing the review. :)
ISN D10iemNewF-700x700.jpg


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When I make a product one day, I would send it to you for review :dt880smile:

These new budget IEMs look like good deals, for sure.
I will gladly accept that! Cheers!
Well, something I didn’t mention is the D10 kind of exists on your ears, then when you really find an album with extended sub-bass, it comes alive. Never have I found an IEM at any price that does such summersaults?


Headphoneus Supremus
For the love of bass
Pros: Build quality is excellent, the cables is fantastic, sounds very good.
Matches perfectly with variety of sources.
Cons: The bass can be huge for some
With a lot of brands coming out into the IEM scene buyers have a lot of options these days and the budget to mid range price range is dominated by Chinese brands that provide excellent value for money.

ISN audio made a wave with their H40 hybrid earphone, both buyers and consumers were impressed by its lower end thump and good amount details. Riding on the success of the H40 ISN audio has come up with a single dynamic driver IEM D10. It houses a 9mm dynamic driver to do all the hard work in the world of multi driver IEMs. It doesn't have any fancy technology behind it either. Priced at $175 it comes in only one color which looks kind of brown under artificial light and dark blue under the sun.

Get one for yourself from here:



My unit came in the older package which is smaller and looks tidy, the newer package is bigger and spacious. The zipper carry case coming with the older package is nothing like the newer premium looking faux leather clasp case. The older package comes with a karabiner but the newer set gives that a miss and adds a cable clip.

What remains the same are the set of tips and the cleaning too.



The D10's shell is made out of resin and it feels fairly solid to the hand. Few layers of resin over the back plate give it a uni-body kind of feel. The semi custom type shell design give is an ergonomical feel inside the ear. The longer than usual nozzle plays a role of giving it a secure feel. The 9mm dynamic driver has a breathing vent just aside the MMCX port.

The D10 is very comfortable inside the ear, there isn't a single bothering attribute to it. It can be worn for hours without any discomfort. The size is not big and should fit most of the ears.



These days there most of the brands are trying to provide better cables with their IEMs and ISN has one of the best cable for under $200. With S4 printed on the cable slider I would like to assume that this stock cable uses a slightly less premium components with the exact wires. Each core has 63 strands of single crystal copper with silver plating on it. The cable has similar aesthetic to the BQEYZ Spring 2 cable but the ISN cable is lighter and suppler. It has little to no memory problem.

The most remarkable feature about the cable is its lack of cable guides, big relief, what cant other brands do this? The 3.5mm jack, MMCX pins and cable splitter barely have any stress reliever. What's interesting is the body of the cable splitter can be moved out of its place with a bit of effort, exposing a simpler rubber tube at work. The cable slider is fairly smooth but doesn't slide down on its own.



The D10 houses a single dynamic driver and has a impedance of 16ohm and sensitivity of 100db making it one of the most compliant IEM I have used for a while. Driving it out of mobile phone is not a problem at all. Pairing it with more powerful sources and AMPs doesn't yield any improvement either. I tried it with the Busron Playmate and it lost some of its lower end volume while delivering faster and lighter mid and treble notes.

If you want an IEM that can be driven without any problem across a handful of sources the ISN D10 should be considered a top contender. Drive it out of any dongle and just enjoy!!



Yes, some brands use dynamic drivers and still manage to deliver a balanced sound but D10 doesn't have any intensions of being on the balanced side. It delivers wholesome amount of bass with plenty of volume. The 9mm dynamic driver doesn't shy away from expressing itself. The overall sound signature is slightly V shaped without any veiling. Tonality and timber have a hint of metallic feel though. The warm and slightly brighter tonality takes me back in memory but thats in past...

I am using the stock white tip with green cores. Switching to wide bore tips takes away the essence of this IEM.



The ISN D10 has bass in its heart. It drivers the whole sound while delivering plenty of thump. The 9mm dynamic driver has excellent sub-bass extension and rumble. This extension can be compared to the much more expensive Jomo Percusion P3. The mid bass has a wholesome and full bodied feel to it, giving a well rounded feel to the lower end delivering a punchy but a not so hard slam. Upper bass deliver very good amount of details and merges nicely into the lower mid region.

The decay speed is slightly on the slower side with a bit of cushy feel to it. It is allows the note to precipitate without much restriction take it very close to bass-head Level. Just like most of the dynamic driver IEMs the D10 has good amount of juiciness and very good amount texture.

Where does it stand? It stands well over the BA based IEMs and is in the league of TFZ Kind series but with better sub-bass presence.


The mid range is slightly recessed while maintaining good energy and transparency. Thanks to good tuning there is no dip in energy or clarity while transiting from upper bass to lower mid region. Notes are aptly agile and detailed for a dynamic driver IEM. Much better than the Moondrop KXXS which feels recessed and veiled. The D10 delivers musically inclined notes with slightly thicker base while curbing on sharpness. There isn't much bite but still leaves an impression. It has nice technicality even without excited or energetic notes. D10 does not have very precise or accurate notes like the DM7 but it is smoother and calmer. Micro details retrieval is very good, the background acts too have nice clarity.

Vocals are a pleasant surprise. Given the vigor shown by the bass the vocals manage to pierce out of bass region. It effortlessly penetrates the plane made by the bass notes. This exhibition of ability shows the quality of tuning that went into it. It does two things, first, it restricts the notes from being sharp and 2ndly it takes out a bit of shine. Those who like a mid forward, slightly energetic, a bit sharp and crisp vocals will find this to be neutral. Both male and female vocals sound similarly impressive while maintaining very good amount of details and texture, let it be Ben Howard or Nina Simone, all of them sound fairly accurate. The upper mid is not sharp while having good energy and transparency. The whole mid range is slightly on the lush side. Notes could have been a bit more agile.


The D10 delivers a fairly good treble region with very good instrumental clarity and details. It does not have plenty of spark or energy like BA based counter parts and is not the most revealing either, the presentation too is on the smoother and musical side.

Transition from upper mid to lower treble region is nicely energetic and is clear of any sibilance or peaks. The D10 has very good leading treble extension as it maintain very good amount of energy and clarity even when it goes higher in FR. Level of details retrieval is nice while keeping the timber acceptably natural. Cymbals and pianos have nice transparency, just don't expect sharp and tingly instruments and plenty of details retrieval and the D10 won't disappoint. It just simply doesn't have a lot of micro details for the detail hogs. Separation and layering is nice with good amount of air and space between instruments. The treble stage is well spread with good density to it. If you love clean and inoffensive sound, the D10 fits the bill.



The ISN D10 has a well expanded stage for an under $200 IEM. It has very good height and depth while the width is slightly on the narrower side. The stage in whole has a fairly big dimension, bigger than the BGVP VG4 and TSMR 2. I love the way it places cues further, exhibiting its sonic abilities, something the BA based IEMs can't take pride in. Nearly 80% of the vocals and some instruments are placed inside the head while majority of the stage is projected outside the head giving it a more open kind of feel. As mentioned earlier the bass takes the center stage but it doesn't spoil the broth, it works much more like a layer and the instruments are placed either side of it.


ISN SC4 ($110):- What is an upgrade to the stock SPC cable? A better SPC cable with pure silver and single crystal strands. The first thing that comes to attention is the bigger stage size. It feels much more expanded in every direction without messing up the distribution of instruments. The bass get deeper with slightly better sub-bass rumble while the mid bass sheds some body delivering equally good amount of texture and details. The bigger change comes with the not anymore V shaped mid range. The Vocals are a bit more forward, more in line with the rest of the spectrum. The whole mid range sounds slightly more organic and textured. Treble gains some maturity with better control over notes and the bigger stage makes it much more enjoyable. The SC4 brings more details and accuracy with much better contrast between background and foreground instruments.

SC4 is a fitting upgrade for any MMCX IEM.



VS BQEYZ Spring 2 ($169):-

The BQEYZ earphone is a massive upgrade to the spring 1 and is one of the best earphones of this year. The Tri hybrid earphone has better resolution and micro details and comes in a metal jacket.

VS TSMR 2 ($169):-

The dual BA TSMR 2 is a more balanced IEM with intimate vocals with slightly better texture. It houses 3 switches which can alter the sound a bit if needed. The 2 has overall better micro details and is more contrasty.

The lower end is much smaller with bass body. The sub-bass not much rumbly and the extension is not as deep as the D1o either. The mid bass give it volume but is still much smaller in volume and the impact is not par. The vocals and mids are much forward and have better texture and resolution, much similar to the Spring 2 while rest of the instruments are slightly on the dull side. Same case with the treble, it has good details and enery but the D10 does better with energy and crispiness. Stage size of the 2 is wide and tall but lacks depth.


If amount of details and a balanced sound is what you are looking out of an IEM, just look away. It has good amount of details but the lower end is nowhere close to being balanced. What the D10 does is it maintains nice transparency while keeping the presentation fatigue free and musical when compared to most of its competitor.

The slightly V shaped sound is not for everyone but is the most popular signature, loved by many and the D10 will please a lot of users too.


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"The ISN D10 has bass in its heart".

"It effortlessly penetrates the plane made by the bass notes".
Detailed and easy to follow review. I like your style of writing.


500+ Head-Fier
Pros: Build quality,
S4 stock cable,
Bass performance,
Fit and Comfort,
Overall Sound Quality
Cons: Bass might be to much for some
Before starting this review, I would like to share technical aspects and package details.

Also, I would like to thanks to Penon Audio for this great opportunity. Here is the link of the ISN D10:



Brand: ISN Audio

Model: D10

Driver: 9mm Dynamic driver

Material: resin

Impedance: 16 Ω @1khz

Sensitivity: 100 ± 3dB @1khz

Frequency response: 20-20kHz

Connector: MMCX

Plug: 3.5mm Audio/2.5mm/4.4mm Balanced


Package Details:

ISN D10 earphone

8 pairs of silicone eartips

Carry case

Clean brush


Test Equipment:

Opus #1


Topping D50s

Earman TR-Amp


Package, Design;

D10 comes in a small box which is same with H40, the only difference is its outer print. Box is like a pomegranate. When you open it there is beautiful ISN D10 and cable, nylon carry case, lots of tips, carabiner, cleaning tool. There are 8 pairs of tips and I really like the green silicon tips. Its sound and fit are pretty good for me. You can attach the carabiner onto the nylon carry case to hang however you wish. Case itself is exactly the same as H40 has, it looks flimsy but it keeps safe your earphone from the outer world. Cable is so beautiful as expected. It is ISN Audio S4 cable which is surprising for a stock cable, especially for its price tag. Cable is 4 braided SPC, it looks and feels premium. It is soft, tangle free, and the most important is, it sounds good. Termination, pins, y splitter are black and it is nice contrast with cable's silver color. When I received the D10, the first thing I realized was its size. It is fairly smaller than the H40 and it provides better fit and ergonomics when you wear it. Body shape is exactly same as H40 except it is %30 smaller and color is different. It is very dark navy color but it is hard to see its original color, especially in low lights. Navy shells combinate with gold ISN logos on faceplate. Nozzle is pretty good in size not short nor long either. Like it's big brother, it has also MMCX connectors. It feels secure and solid, you can switch between your aftermarket cables. Overall build and material quality are pretty high and it provides more than its price tag.



The D10 is a very exciting earphone in sound and I feel it since at the first second of my listening. My favorite frequency of the D10 is absolutely its thunderous bass frequency. Basically, bass is a bit more than my personal preference, but its performance is so impressive that you want to listen that bass slam all the time. Besides bass, the performance of treble is also impressive. You think that such powerful bass will dominate and suppress all frequencies, but the D10 does an extremely successful job here too. Treble is definitely not recessed or rolled off. It has a very well extended, clean and detailed presentation. As expected from V shape presentation mid frequencies are slightly recessed and laid back.

The treble is very detailed and the resolution is very good compared to this price band. The instrument separation is not competing with the totl level, but it can give headaches to many headphones in the $ 300 band. It has good extended and sparkled trebles and, I did not hear any sibilance or harshness with any source that I've listened to. The airy presentation in the treble also helps the soundstage to be opened, making the instrument distinction more successful. You can hear up to small vibrations in stringed instruments, which promises good performance in terms of micro detail.

Mid frequencies sit behind other frequencies due to V-shape presentation. I found its performance more successful in female vocals because the lower mids are not full bodied. Mids does not have a huge amount of detail and resolution, but I can say that it is very successful according to this price band. There is coloration in the mid frequencies as well as in instruments.

Bass performance of D10 is my favorite frequency. The bass is so powerful, it reminds me of Legend-X as soon as I listened and I can say that the bass is almost the same in quantity, as far as I remember. Although bass does not suppress and crush frequencies in general, I can say that it dominates the general sound character. It can also create a compression towards the lower mids. The sub-bass can go quite deep and creates a club atmosphere to your ear. Listening to music like EDM is incredibly enjoyable. I can easily say the amount of bass at bass-head level.

D10 has pretty wide soundstage and, it is easy to positioning instruments. Soundstage depth is also sufficient but not as good as width. Imaging and layering are above its price and provides clean and easy to hear instruments and vocals in stage.



D10 vs Final Audio E5000

Final Audio E5000 is a well-known model in the community and its easy to love the tuning, deserves its fame. Both earphones material and build quality are fantastic. Both have MMCX connectors with SPC cables. They have 1 single dynamic driver per inside. E5000 is stainless steel while D10 is made of acrylic. Both earphones are great in comfort but D10 provides much better sealing and isolation due to its design. E5000 needs some correction in ear every 20min or so if you are walking. Sound; E5000 is smooth, vivid and rich while D10 is more dynamic and energetic. D10 is better on sub-bass presence and it is more in quantity while E5000 is smoother and more rounded. D10 sub bass power is enormous and it is slightly slower than the E5000 but it doesn’t mess up with fast passages anyway. Mids are meaty and bold on E5000 and it has more smooth, natural presentation while D10 has slightly recessed and thinner on lower mids. Vocals are more pronounced and forward on E5000 and it feels narrower on stage. D10 is centered and slightly laid back on vocals but it has nice airy presentation. Trebles are more forward and detailed on D10. E5000 is smooth and creamy, but it is hard to catch the details at the same time. D10 provides better details and resolution in this sense. Soundstage is wider and deeper on D10 while E5000 has more limited present. E5000's sound is overall more organic, smooth, dark and tube like while D10 is more lively, dynamic and excited.



D10 vs JH Billie Jean

It is going to be a balanced armature vs dynamic driver comparison but I would like to compare it. Billie Jean is 2 times expensive than the D10 and it has 2 balanced armature drivers per side while D10 has dynamic driver. Package content is similar with Billie Jean (BJ), it also comes with nylon carry case, various tips, cleaning tools. BJ is made with high quality ABS plastic and its body shape is slightly smaller than D10, but D10 provides better fit and seal on ears. BJ comes with flimsy plastic stock cable while D10 comes with S4 which is much more superior. Sound is similar but D10 has more on every frequency. BJ has quite strong and powerful bass but still it cannot match with D10. D10 hits more, goes deeper, and it is more dynamic. Dynamic driver is always my first choice in terms of bass performance and there is no compromise here too. Only thing that BJ is better on speed. It has better recovery time while D10 is noticeably slower. Both earphones have recessed mids. Low mids are more pronounced and it makes male vocals better on BJ. Vocals are slightly laid back and recessed on D10 while BJ has more forward and natural presentation. Trebles are more extended, sparkled and detailed on D10 which provides more resolution and micro details. BJ has smoother and easy-listening trebles. Soundstage is wider and deeper on D10 and instrument separation is better.



D10 vs Rhapsodio Saturn

Rhapsodio Saturn is a very interesting earphone and I like its creamy, vinly like sound. It has also 1 dynamic driver per unit. Saturn is pretty big in size but still it is good on seal and comfort. D10 takes advantage from its small size and it is one step better both comfort and seal. Saturn has the most smooth, relaxed IEM I’ve ever heard so far. Bass is smoother, warm and organic on Saturn and quantity is less than D10. It has good impact and power but it is not bass head earphone. D10 goes deeper, hits harder and has much more in quantity. D10’s thunderous bass is so exciting to listen and shows better performance on EDM like genres. Mids are lush, warm and forward on Saturn. It has tube-amp sound and vocals are velvet smooth. Trebles are more pronounced, extended, and sparkled on D10. D10 shows better technical performance and easy to hear micro details but also it is less organic and natural. Saturn is more realistic and easier to listen for long hours. Soundstage is better on D10, it is wider and deeper an also instrument placement are much better.




ISN Audio is a fairly new company, and the D10 is their second earphone I have reviewed. Like the H40, D10's performance is definitely above its price. Dynamic, vibrant and fun with incredible bass power and detailed treble presentation that makes it great earphone for who loves its sound signature. Also, it has enough bass to make bass-heads makes happy. Material quality and workmanship are also at the top-notch level. The S4 stock cable also comes with D10 sold separately which is great. I can easily recommend the D10 to anyone who loves electronic music.


100+ Head-Fier
Pros: Bass Performance,
Overall clarity, airiness and transparency,
Look, Fit and Comfort,
Comes bundled with the ISN S4 Upgrade cable,
Cons: Needs at least 150 hours of burn-in,
Upper Treble Roll-Off
ISN Audio D10 IEM Review

ISN Audio is a relative new Chinese brand that is producing portable audio gears like Earbuds, In-Ear Monitors and Cables. The ISN Audio D10 is an In-Ear Monitor with a 9mm diameter Single Dynamic Driver which is available with the new S4 OCC Sliver-plated cable that can be purchased with 3.5mm TRS, 2.5mm TRRS and 4.4mm headphone plugs.



I would like to thank ISN Audio for providing me the D10 IEM sample via Penon Audio for review purposes. I am not affiliated with ISN Audio and Penon Audio beyond this review and these words reflect my true and unaltered opinions about the product.

Link to the original post:

The ISN Audio D10 is available on Penon Audio for 175,00 USD under the link below:

Package and Accessories:

The ISN Audio D10 is coming in a small rectangular box that is wrapped with a cardboard which shows the illustration and some brandings of the D10 In-Ear Monitor.


The box includes the following items;

  • 1 pair x ISN Audio D10 In-Ear Monitor
  • 1 piece x Detachable Cable with MMCX connectors
  • 6 pairs x Silicone Ear Tips
  • 1 piece x Zipper Case
  • 1 piece x Karabiner
  • 1 piece x Cleaning Tool


Design and Build Quality:

The ISN Audio D10 is an IEM with a nice semi-custom like monitor shell which is made of resin material in dark purple (purple-black) color with a glossy finish. Inside the D10 is a 9mm diameter single dynamic driver.


On the front of the monitor shell is the so called faceplate that features the ISN Audio brand logo which is inspired by a harp instrument in golden color.


At the rear side of the monitor shell is sound nozzle and the surface which fits to your ear concha thanks to semi-custom shaping.


The sound nozzle has a fine metal mesh in gold color on the top to prevent the insertion of dust and earwax partials inside the monitor. Near the nozzle is a small vent that is needed for the 9mm diameter dynamic driver.


On the top of the housing is a second vent and the MMCX (Micro Miniature Coaxial) female connector which offers a pretty secure and tight connection with the male connector of the detachable cable.


The overall build quality of the monitor is top notch!

The Cable:

The ISN Audio D10 comes with the S4 detachable cable that is also sold separately. The S4 is a 63 Cores 4 Strand cable made of OCC Sliver-plated copper wire. The cable features MMCX male connectors.


The MMCX connectors have a metal housing in black color with L & R markings and two rings on each connector in gold color which gives the S4 a nice stylish look.


The cable has a soft TPU coating and features a metal Y-splitter and a metal chin slider in the same black color.


The Y-splitter sports the ISN Brand logo and two gold rings/circles while the chin slider shows the S4 branding and has one gold ring.


The S4 has a straight profiled headphone jack which is available in 3.5mm TRS unbalanced and 2.5mm TTRS or 4.4mm TRRRS (pentaconn) balanced variants. The housing of the headphone jack is made of metal in black color and features the same gold colored rings that we have seen on the other metal part of the S4.


The S4 can be purchased separately under the link below which is also available with the 2-Pin connector variant.

Fit & Isolation:
The monitor shell of the ISN Audio D10 has an average size and fits perfectly in to my ears. It offers a pretty good isolation for an In-Ear Monitor with a universal shell and is comfortable to wear for longer listening periods without to hurt my ear especially the area that is called as ear concha.


The ISN Audio D10 is a very easy to drive IEM with a impedance of 16Ω and a sensitivity of 100dB which makes it compatible with relative weak sources like Smartphone’s, Tablet’s and DAP’s with low amplification.

Technical Specifications:
  • Driver Configuration : 9mm Diameter Dynamic Driver
  • Impedance : 16 Ω @1kHz
  • Sensitivity : 100 ± 3dB @1khz
  • Frequency response : 20-20kHz
  • Connector : MMCX (Micro Miniature Coaxial)
  • Plug : available in 3.5mm TRS, 2.5mm TRRS or 4.4mm TRRRS variants
  • Cable length : approx 120cm


Equipment’s used for this review:

  • IEM’s : ISN Audio D10, Campfire Audio Comet, Final Audio E5000
  • DAP&DAC’s : iBasso DX160, FiiO M11 Pro, FiiO Q5s

Albums & tracks used for this review:

  • Rush’s – Leave That Thing Alone (Flac 16bit/44.1kHz)
  • Liquid Tension Experiment 2 – Acid Rain (Flac 16bit/44.1kHz)
  • Armin Van Buuren – Vini Vici (Spotify)
  • Lorde – Royal (Flac 24bit/48kHz)
  • Tom Player – Resonace Theory (16bit/44.1kHz)
  • Massive Attack – Angel (Flac 24bit/192kHz)
  • Portishead – The Hidden Camera (MP3 320kpbs)
  • Opeth – Damnation (Wav 16bit/44kHz)
  • Metallica – Sad but True (Flac 24bit/96kHz)
  • Megadeth – Sweating Bullets (Flac 24bit/96kHz)
  • Slayer – Angel of Death (Flac 24bit/96kHz)
  • Gogo Penguin – Raven (Flac 24bit/192kHz)
  • Otto Liebert& Luna Negra – The River (DSF) – Binaural Recording
  • Vivaldi – Le QuarttroStagioni “The Four Season” (Wav 24bit/88kHz)
  • Elton John – Your Song (Flac 24bit/192kHz)
  • David Bowie – Black Star (Flac 24bit/96kHz)
  • Dave Gahan – Kingdom (Flac 16bit/44.1kHz)
  • Eric Clapton – Unplugged Album (Flac 24bit/96kHz)
  • First Aid Kit – My Silver Lining (Flac 16bit/44.1kHz)
  • London Grammar – Interlude (Live) (Flac 24bit/88kHz)
  • Laura Pergolizzi – Lost On You “Live at Harvard and Stone” (Wav 16bit/44.1kHz)

The Sound:

The ISN Audio D10 shows a V-shaped sound signature and is focus on the top and low end, while the general tonality is slightly warmer than neutral. The bass is strong, impactful and pretty fast, the treble range is airy and highlighted, while the midrange is fairly clear but a bit recessed.

PS: The ISN Audio D10 needs a burn-in for approx. 120 – 150 hours to shows its true potential and to tame the upper midrange and treble region.


One of the focal points of the ISN Audio D10 is the lower frequency region that is punchy and energetic, which gives the overall presentation a pretty dynamic character.

The subbass of the D10 is more highlighted than the midbass region and shows a good level of depth, rumble and extension especially for a relative small 9mm diameter dynamic driver. The subbass tuning is ideal for genres like pop, electronic, rnb etc. while it doesn’t sounds overdone.

The midbass on the other hand is slightly less pronounced compared to the subbass region and shows a punchy, dynamic and full bodied character. Instruments like cross drums do sound accentuated; snare drums are slightly bassy and pretty fast, while bass guitars have a warmish and full bodied tonality.

The bass of the ISN Audio D10 is in general fairly fast, tight and controlled and will satisfy from trance, pop and rnb music up to faster genres like metal music.



The midrange of the ISN Audio D10 is slightly recessed compared to the bass and treble range due to the V shaped sound signature and has a slightly warmer than neutral tonality. The upper midrange of the ISN Audio D10 is more pronounced than the lower midrange region.

The detail retrieval of the midrange is pretty good, while the general presentation of this region is clean, spacious and pretty transparent.

The vocal performance of the ISN Audio D10 is in general successful. Male vocals such as B. B. King or Eric Clapton are musical and pretty clear, while female vocals like Laura Pergolizzi or Hannah Reid are transparent and lively. Female vocals are slightly more successful due to the upper midrange character.

The instrument tonality of the ISN Audio D10 is slightly warmer than neutral and do show a vivid and clean presentation. Instruments like pianos are slightly bright, pounced and lively, while guitars are transparent and pretty musical.


Upper Midrange and Treble:

The upper midrange of the ISN Audio D10 is strongly highlighted and gives the overall presentation a crisp and lively character. The upper midrange is more forward positioned than the treble range and sounds also more detailed. The transitions are in general fairly soft and controlled without to show remarkable drawbacks such as lack of extension.

The treble range of the ISN Audio D10 is focused to the lower treble which means that there is a slightly roll-off in the treble range after a peak around the 5 kHz region. The lower treble region (presence) is more detailed compared to the upper treble (brilliance). The treble range needs at least a burn-in period of 150 hours to show its true potential, which was a bit sharp at the very beginning of my first contact with the D10.

Instruments like hi-hat’s and cymbals in genres like jazz or metal music are pretty highlighted and do show a good level of extension for an In-Ear Monitor at this price category.


The soundstage performance of the ISN Audio D10 is pretty good for an In-Ear Monitor at this price range and is successful in terms of instrument/vocals placement and separation. The soundstage shows a nice amount of air and has an above average wideness. The soundstage depth on the other hand is on an average level.

Some Comparisons:

ISN Audio D10 versus Campfire Audio Comet:

The subbass region of the ISN Audio D10 shows more rumble/ quantity compared to the Campfire Audio Comet and is also is superior in terms of depth and extension. The midbass region of the Comet is slightly more highlighted and shops a tad more impact. The ISN D10 has the upper hand in terms of bass speed and control.

The mirdange of the ISN Audio D10 has a brighter tonality with better level of airiness and clarity, while the Campfire Audio Comet shows a slightly warmer tonality and a tad more fullness which makes it a tad more emotional compared to the ISN D10.

The lower midrange character makes the Comet slightly more successful with male vocals, while the ISN Audio D10 is superior in terms of female vocal performance. Instruments like violins and cymbals are more detailed with the D10, while I prefer the Comet for violas and the contrabass. The upper midrange of both the CA Comet and of the ISN D10 is highlighted with a boost that is noticeable around the 3 kHz region.

The lower treble range of the ISN Audio D10 has a better level of extension and shows a fairly controlled roll-off towards the upper treble area. The Campfire Audio Comet on the other hand has a noticeable roll off in the lower treble range that is less detailed compared to those of the ISN D10. The upper treble range of the Comet is more highlighted compared and slightly more detailed compared to the ISN D10.

The soundstage of the ISN Audio D10 has the upper hand in terms of soundstage wideness, while the depth of the stage is nearly identical with both In-Ear Monitors.


ISN Audio D10 versus Final Audio E5000:

The most noticeable difference when you swipe from the ISN Audio D10 to the Final Audio E5000 is the drivability. The D10 is a much more efficient IEM compared to the E5000 which needs a more powerful source to shows shine.

Both the Finals Audio E5000 and the ISN Audio D10 are successful IEM’s in terms of subbass performance. The subbass region of the D10 is slightly more highlighted compared to the Final Audio E5000 and has the upper hand in terms of depth and extension.

The midbass region of both IEM’s shows also similarities when it comes to impact and extension, while the ISN Audio D10 has a slightly advantage in terms of control and tightness.

The midrange of the ISN Audio has a slightly brighter tonality and has the upper hand in terms of transparency and airiness compared the Final Audio E5000 because of the more pronounced upper midrange character. Male colas do sound slightly fuller and warmer with the E5000, while the ISN Audio D10 is superior in terms of detail retrieval and clarity of female vocals.

The upper midrange and lower treble region of both IEM’s is more pronounced compared to the upper treble region. The upper midrange and lower treble range of the ISN Audio D10 is slightly more highlighted compared to the E5000 and has the upper hand in terms of airiness, detail retrieval and extension. The E5000 has a smoother and more forgiving treble presentation.

The stage of the ISN Audio D10 is slightly more expansive and shows a better level of airiness and separation. The soundstage of the ISN D10 shows better depth compared to the Final Audio E5000, while the E5000 has the upper hand in terms of depth.


ISN Audio offers with the D10 IEM a highly engaging presentation thanks to its great bass performance, good detail retrieval and overall level of clarity and airiness. This sound is packed in to a very comfortable and stylish looking monitor which comes with lots of accessories and the ISN S4 upgrade cable that is available with single ended and balanced headphone plug options.

Thank you for reading!
Many thanks for your review! :gs1000smile:
You wrote as “Con”:
Needs at least 150 hours of burn-in
In my opinion burn-in a new IEM is absolutely normal. Nothing wrong with it.
Thank you for your kindness :) Yes, burn-in is maybe not a real con, but many people give their decision after the first 10 hours.


Member of the Trade: RikuBuds
Pros: Unique "sub-woofer" like sub-bass
BIG soundstage
Impressive detail retrieval
very good instrument separation
excellent cable and even more so when you can actually choose between standard SE 3,5mm or balanced 2,5/4,4mm
Cons: Timbre
Treble, affected by the "sub-woofer" bass and sometimes sibilant or sharp
Mids, timbre affects the mids
Overall bass not very clean

EDIT 2020-10-20: From 4.5/5 to 3.5/5. The Ibasso IT00 and the Fiio FH3 are somewhat similar in profile but performs better in SQ and in the case of the FH3, also better technicalities. Price is too high and the good value from the cable is lost now that we got a lot of great budget cables (20 usd range) with the Faaeal litz copper, Tri Through, Kbear Rhyme and the Kbear Limpid cables.

EDIT 2021-07-11: demoted the rating from 3.5/5 to 1.5/5 due to the GS Audio GD3A.

: Bought at Penon Audio with their early bird discount at my own expense. Burned in for at least 50 hours.

Price: 175 usd (early bird 135)


Brand: ISN Audio

Model: D10

Driver: 9mm Dynamic driver

Material: resin

Impedance: 16 Ω @1khz

Sensitivity: 100 ± 3dB @1khz

Frequency response: 20-20kHz

Connector: MMCX

Plug: 3.5mm Audio/2.5mm/4.4mm Balanced

Cable length: 1.2M



ISN D10 earphone

ISN S4 4 core SPC cable

8 pairs of silicone eartips

Carry case

Clean brush


Cable: you actually get the choice if you want a balanced 2.5/4.4 mm connector or the standard 3.5 SE connector, so that is great for people that want to use a balanced cable. The cable itself is priced at around 60 usd and there is no need to upgrade it (I prefer it over cables such as the 175 and the 173, both of them costs more than 2 times if not 3 times of the S4). It has a working chin slider, indicator for L/R (this should be the standard for all cables, a clear and visible L/R indicator) and no ear hooks.


Build: entirely made out of resin, has a vent hole and has a lip on the nozzle (metal dust filter) so tips stay on good. A very compact build and should fit those with small/medium sized ears perfectly, although for me I would prefer it just a tiny bit bigger.

Fit: as mentioned, since the build is very compact it should fit most people. For me it is one of if not the best fitting iem because when you try to remove it, it feels like having an octopus´s suction cup on your ears. The seal is very good with this and I see no way for it to fall of during use or even needing readjustment. (very hard to remove, so that should say a lot about its fit.) There is some driver flex for me though.

Comfort: since it has such a tight seal, it isn’t that good when it comes in comfort. I cannot use it for a long time because my ears get sore from the tight seal. (my skin in general is very sensitive so keep that in mind, for you guys with a more robust skin you shouldn’t have any problems with the comfort unless you have really small ears, in which you will probably have problems with the fit which leads to comfort problems)

Isolation: very good isolation even with a vent hole, most likely it is the tight seal that makes the isolation so good along with the build that covers the entire ear.

Setup: Fiio M11, stock cable (4,4) and Acoustune AET08

Lows: versatile bass, while it is boosted quite a lot it can rumble and be punchy. Meaning that on most bass focused songs it is a very good match since the bass In the D10 is able to reproduce every kind of bass. Sub-bass focused but mid-bass is not far off. The only thing lacking with the bass is texture, it cannot match some other iems (which I come to in the comparison section).

Mid-bass: punchy and tight mid-bass, quality is good and stays away from the mids. While it is tight and punchy, I wouldn’t recommend it for rock/metal because the overall mid-bass isn’t very clear and clean. You can hear it in this: , while the bass certainly is tight here, the overall low-end is quite muddy and makes it sound bad (due to the sub-woofer like sub-bass)

Sub-bass: versatile sub-bass, punchy and can rumble. Focus here rather than mid-bass which makes stuff like EDM very good with it. The meat and potatoes of the D10. Sounds like a sub-woofer so that is very impressive, but the texture isn’t anything special, and also makes the overall bass sound muddier than normal (due to the sub-woofer sound).

Mids: leaning a bit more towards female vocals due to the 3,5k peak but otherwise a very good balanced mid-section. What is most impressive is that even with the big bass, the vocals are still not swallowed by the bass and has its own spot (not mid forward though and not recessed either).

Female-vocals: detailed and crisp, but since the timbre is not that impressive it is not as natural as some other iems.

Male-vocals: a bit too bright for male vocals makes it sound less natural than the already non-natural female vocals. Unexcepted since the D10 has so much bass.

Highs: the treble is a bit sharp. There is a sharp peak at around 3,5k (very similar to the shuoer tape´s peak but definitely not as much) that makes it sibilant on some tracks for example this ( ) being sibilant and this ( around 1 minute to 1 minute 10 sec for example) being very sharp but not quite at the sibilance level. Overall quantity isn’t that much nor is it too little, so it has treble energy while not sounding too bright but definitely leaning on the brighter side.

Soundstage: One of the biggest soundstages, it is definitely the biggest out of all DD sets I have but not quite on the same level as the LZ A6 for example.

Tonality: a very balanced iem where even though the bass and in some cases the treble takes the focus, the mids are never recessed but there is a bass and treble boost. Not very good timbre due to the treble, it doesn’t have as good timbre as the blon 03, Final Audio E5000, Audiosense DT200 or even the tribrid LZ A6.

Details: very impressive amount of details, even more so when you factor in the amount bass quantity it has and it can still keep the details without losing any due to the bass.

Instrument Separation: very good separation, the technicalities are extremely well done for a single DD which in most cases usually aren’t that good in technicalities. (you can in a way say that the technicalities are more like a BA set than a DD because BA usually have better technicalities while having worse timbre, which is the case in the D10 although it definitely sounds like a DD make no mistake about that).

Songs that highlight the IEM:

Good genres: EDM, Dance, hip-hop, orchestral non-classic

Bad genres: Rock,metal, Jpop, acoustic songs/genres


Blon BL-03(mesh filter mod):
sub-bass is more textured, tighter, faster and extends more on the D10. Mid-bass quantity is higher on the 03 (but since the sub-bass sounds like a sub-woofer it does affect the mid-bass in a bad way), D10 is tighter, faster and more textured. Mids are a bit more forward on the 03, both female/male vocals. Treble sounds more natural on the 03 but it also has a bit more quantity.

Soundstage, details, separation are much better on the D10 but don’t come close in timbre. 03 is a much more natural and correct sounding iem (even with its bass boost). D10 is a fun iem that has the sub-woofer like sub-bass that makes bass focused genres very good with it. 03 is a more versatile set since it sounds more natural and clearer.

LZ A6 (pink filter): Treble quality is miles ahead of the D10, quantity is a lot more though so risk for sibilance is higher (not for me though). Extends much more and also has a lot of air on the A6 (too much to sound natural but it sounds very unique due to it).

Mids are perceived as more forward due to it having a more controlled and lesser bass quantity than the D10. Vocal balancing between male/female vocals are a bit better on the A6, not leaning as much to the female vocals as the D10 do.

Mid-bass has a bit more texture on the A6 and it is much faster and tighter, making it a very clean mid-bass. Sub-bass keeps the texture, speed and tightness advantage over the D10 but the D10 has that unique sub-woofer sound to it. So, it extends a bit more and rumbles more.

Soundstage, separation, details and timbre is much better on the A6. A6 is a more natural, versatile iem and also much more treble-energetic than the D10. D10 is better if you are treble-sensitive (it does have a bigger 3,5k peak though) or if you want a more sub-woofer like bass with rumble over tightness/speed.

Shozy Form 1.1: D10 has more sub-bass quantity, rumbles more, while the 1.1 has more texture, tightness and speed. Mid-bass on the 1.1 is faster, tighter, cleaner and more textured. Mids are more forward on the D10 than the 1.1 and also have better quality. Treble on the D10 is sharper, while being warmer (quantity lesser) and sounds more unnatural than the 1.1 (1.1 doesn’t have a very natural treble either though).

Soundstage is bigger on the D10, but separation, details and timbre are better on the 1.1. D10 is better for EDM and similar music, while the 1.1 is a more versatile set.

Conclusion: Overall since you are getting such a good cable, build, fit, isolation and unique sub-woofer like sub-bass I believe it deserves a 4,5/5. But if I were to judge it solely on sound it is a 4/5.

Cable source:
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@Dsnuts to me if they want an iem for metal/rock I would go for the LZ A6 instead, with its fast,tight and very clean bass it is very good for rock/metal. Although at the price of 135 usd it isnt really a problem because of the cable. (I mean I even prefer the S4 cable over 175 for some iems so...)
I currently have UE Triple fi10 from 2008. Would these be a worthy upgrade? Or should I go for something like LZ A6?
@soldiersixteen I havent heard nor know how the UE triple Fi10 sounds like, but my favorite iem and best recommendation is the LZ A6.


Headphoneus Supremus
Pros: Higher end build, semi custom design. Extremely well implemented single dynamic design excelling in coherency, clarity, detail, imaging, timbre, sound stage with an airy sound. Energetic treble with good extension, clean mid range with good use of space. High quality bass to extended sub bass rumble. Comes with a highly regarded premium ISN S4 cable worth $58.90 by itself. Above average isolation and comfort.
Cons: Your gonna wish your other in ears had a similar high quality cable that came with it.
ISN has been creating some very intriguing designs lately and for a company that was previously just known to produce some outstanding IEM cables has now started to focus on some well regarded IEMs. The H40 is not new to the scene now as I had the privilege of introducing their well received hybrid IEM to headfi toward the end of last year.
ISN D10 Left, ISN H40 Right.

The D10 is a follow up product from the H40 which once again shows how apt the ISN crew are at tuning. Here we have a similar all resin design but this time utilizing the tried and true single dynamic design. This resin design is a semi custom shell design that is common nowadays. The shell is very similar and shape of their previous H40 but now a bit more slimmer and smaller physically in design. Which addresses a few guys that took some issue with the fairly bulky yet ergonomic design of the previous H40. The shell is now at a moderate medium in size instead of the large shell of the H40. Comfort is excellent and fits my medium sized ears without any fatigue or pressure points.
Another aspect that has been upgraded is the pack in cable. The cable that now comes with the D10 is the well regarded ISN S4 a 4 core crystal copper plated with silver cable that by itself costs $58.90 to be exact sold here. As of writing there is nothing but 5 star reviews regarding this cable. I can write an entire review just based on the ISN S4 but just know you're not getting some cheap thrown in cable. It will most definitely be an upgrade to most included cables that come with your in ears. Why does this matter? Well that just eliminates the need to upgrade your cable. In fact when ordering you can order the ISN D10 with any termination you want to use on your sources. This is always a plus. I wish all manufacturers would take note of this. Very appreciated that you can just get a balanced ISN S4 with your D10 right away. Props to ISN for this.
ISN’s entire package comes to you inside their rectangular semi hard zip up case. 3 types of silicone tips, a cleaning tool, ISN S4 cable and the earphones themselves. This minimal packaging allows ISN to give it to you where it counts. This packaging isn’t going to win an award for presentation or have a huge variety of accessories. ISN is all about where it counts. A very high quality high value IEM for your hard earned cash.
D10 Sound impressions was based on using them in real world situations using my DAPs Fiio M15, Ibasso DX160, Shanling M5s, Shanling M3s. IFI Black label.

The first thing that hits you when you hear the D10 is just how spacious and airy the sound comes at you. Of course this isn’t anything new as the H40 has that spacious sound. It seems to be something of a “house sound” design that ISN is going for. Your not going to hear an ISN earphone that sounds average in sound stage. The D10 follows the H40 in that regard. The stage is above average in width and shows a good amount of depth. Not the deepest sound as that is where I feel the H40 is better. D10 being a single dynamic design improves on the coherency factor due to being a single driver design.

Treble of the D10 has a good amount of perceivable energy. Has a clean, crisp, detailed emphasis with the right amount of extension. Main focus for treble is lower treble and with very good micro details in the region. The overall sonic quality is energetic due to the ample treble emphasis. Don’t mistake treble energy with treble fatigue. It does a fine job of not crossing over the fatiguing line when listening to the D10. A good way to test how much treble can fatigue is if you can listen to Trance music without fatigue. D10 passed this test with no issues what so ever. Treble shows no grain but comes alive when called for and has an equal footing in emphasis to the bass end. The treble shelf from 3khz-4khz brings a good amount of clarity and precision for upper mids and lower treble. A lower emphasized treble peak at 7khz and then even a lower one at roughly 13khz. The treble is tuned with detail and energy and is not prone to flaws in the region.
ISN H40 Left, ISN D10 Right.

Mids bands of the D10 take a slight step back from treble and the bass end but due to the excellent imaging and clarity the mids don’t feel like it is being overshadowed. Vocals actually sound excellent on these. While not as forward sounding as the H40. Mid band reach and layering is impressive for a dynamic design especially at this price. This slightly laid back mid range design allows for the stage of the D10 to have a width that is not too common among in ears. Lower mids has a steady rise toward the mid bass and even greater toward sub bass. This allows for a clean, clear detailed mid band presentation that once again has no perceivable graininess or unevenness. The one aspect I have learned about how sound tuning affects your perception of stage and scale is if your earphone has a forward mid section that lessens the stage perception. These give you that grand hall sound and that is a part of the design.

Bass has the most prominent energy coming from the sub bass regions. What you're getting is what I like to call a technical fun sound tuning. So I will say you have to be a fan of bass emphasis in general to understand this tuning. These have a sub woofer like effect due to the strong sub bass emphasis. If you sound preference leans toward forward mids and not too much bass emphasis. These might not be for you. However if you love a good emphasized tight low end punch with a strong textured rumble in the sub bass. These will bring a smile to your face.

The D10 will reach the deepest of notes with little effort. It has zero roll off at 20hz. Your tracks that have some low end rumble? These will show you just how much low end rumble is proper. Subbass is really the star of the show here. Bass has a fairly quick decay in the mid bass region. But has that staying power for them low notes. Rumble in the jungle has a new meaning. One thing I found out during my testing period for the D10 is. This may vary depending on how your ears are shaped, but for me. I was able to increase and or decrease perceivable bass emphasis just by loosening the fit of the ear pieces a touch or pushing the pieces in for a tighter fit to increase bass. Bass adjustment on the fly I like to call it.

A technical designed fun signature means you're gonna feel them double kicks for metal, while the upper mids emphasis gonna give you that guitar crunch proper screams. Means these will rumble your face off for hip-hop. Technical in that you can hear your orchestral tracks with great clarity and properly defined imaging. Then come full bore for some Slayer. Sound separation due to that wide spacious sound gives room for them instruments. Sound is versatile and will have you hearing your bassy tracks proper. Traditional bassy in ears are not gonna get you this type of clean sound with your bass. And for that alone these are worth a look. I had some fun with this one and, by golly I think ISN has done it again. They have created a very likable sound I do have the word "fun" in the sound description. It marries a technical ability in much higher end in ears with a very likable sub bass emphasis that is missing in so many in ears. Does your in ear sound clean has an airy wide stage with a bass rumble of a sub woofer?

So on this portion we have some comparisons to some comparable in ears.

D10 vs H40.
ISN H40 Left, ISN D10 Right.

H40 has the fuller bigger sound in general but with a more forward more dimensional sounding hybrid design. I consider one of the essential in ears from last year. ISNs debut in ear will be one for the ages and I feel leaves a high bench mark for the company. The D10s have a more leaner mid range but has slightly more clarity in the region. H40 has the more dimensional better layered mid range due to the BA it is using. The treble emphasis has some similarities but the D10 does a better job of having energy without adding vocal flaws or grain better than the H40. H40 does have a slight emphasis peak in the 7khz range where the D10 does not. So that might be the main difference here.

Bass emphasis is tighter on the D10 with a quicker decay. Sub bass emphasis is similarly extended but has a bit better texture on the D10. Which is surprising since the H40 has a dedicated dynamic for the hybrid. When taken as a whole I feel these two compliment each other in the way the sound presents itself. The H40 is very full bodied, dimensional and musical while the D10 has it’s wide stage, neutralish mid range with great clarity yet still retains that bass end for people that love their low notes. It is the yin and yang of sound signatures.

D10 vs NF audio NA1
NA1 is tuned to have a reference type of definition. It has a cooler tonality due to the treble extension, clarity and detail. If your a treble guy or a macro/micro detail guy. NA1 will be enlightling for you. The D10 has more in the way of sub bass emphasis vs the treble skew U fr tuning of the NA1. Isolates slightly better. NA1 is more for discriminating detail oriented listen. The D10 is more you can listen to it the whole day, enjoy a punchy bass w excellent low end rumble, engaging and fun to listen to all day type of listen. NA1 wins at Macro details more so than the D10 but the D10 makes up for that with a better well rounded overall easier to listen to tuning.

D10 vs NF NA2.
So basically in my estimation the D10 is actually a better, more refined version of the NA2. NA2 tones down the treble skew of the NA1 and is tuned very similarly to the D10. Tonality and sound balancing is similar. I feel the resolution and airy stage of the D10 is where the D10 is worth the extra. Has better technicalities, stage and overall details over the NA2. For enthusiasts that want something similar to how I described the D10 but cheaper will do well with the NA2 here. Sound Fr should be identical in approach but the D10 is more premium in design and overall refinements over the NA2. NA2 is like a little brother of the D10. The most identical of all the earphones I have in comparison sonically. The D10 is somewhere in between the NA2 and NA1 in sound design so while not exactly the same sonically, I feel it comes more closer to the NA2 than NA1.
Bonus pic!! Your seeing the newest iteration of the ISN D10. This is the picture that was sent to me as it will be the new ISN D10 color. A dark blue vs the dark purple that was initially used. They also colored the ISN S4 with a blue tint to the sheathing on the cable to match the dark blue of the new ISN D10.
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Comparisons are definitely helpful and that is a nice cable.
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Thanks for the nice review! Which penon iem will pair well with hiby r5? i prefer natural sound with slight bass boost and soft treble with good extension :) this or penon sphere?
It is like your describing the Penon Spheres. Those are a marvel for being a single BA. These are more V shaped Fr. Meaning they have more treble sparkle and sub bass rumble the sphere but from what your wanting it seems the Sphere is what you are looking for.