ISN D10 Review: Lush Basshead not-too-guilty pleasure

-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

-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 too…so 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 too…one 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:

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