Tanchjim Oxygen


100+ Head-Fier
Tanchjim Oxygen Review
Pros: Build quality, Packaging, Attention to details/technical abilities, Well tuned with great extension, Soundstage/Imaging/Tonality
Cons: Fit and short nozzle
More reviews at www.perrivanaudio.com

Driver Setup: 1 Dynamic Driver

Price: 280 USD



Disclaimer: This review set is a demo set graciously lent to me by Daniel at Oardio and the review is written of my own accord and all thoughts are my own. The Tanchjim Oxygen is available for purchase from Oardio through their website should you find yourself interested in a pair.

This is a review for the Tanchjim Oxygen the older brother of the Hana, the "yin" of the "yang" that we reviewed previously. The Oxygen was Tanchjim’s earliest flagship model and established a name for itself with its tuning and sonic performance. With the Hana, we shall see how the former fares against the new kid in the block as well.

Accessories and Build Quality (Score: 9/10)


Very similar to the Hana except for the colourway, the Oxygen also comes in a cube-shaped box which also follows the concept of the Oxygen itself that lies within. The overall unboxing experience felt rather premium but slightly less fancy than the Hana which I do not really fault it as it was an earlier model. It comes with a nice leather case, 2 sets of ear tips and 2 sets of cables which I appreciate a lot as they really do feel like a complete package and everything you might need.

Build wise, the IEM itself is made out of metal and definitely capable in terms of durability and toughness when it comes to knocks and bumps but however, it is quite susceptible to scratches which may affect its aesthetics but in terms of quality, tanky-ness, and quality checks, the Oxygen scores!

Fit (Score: 7/10)

As per majority of the people that had the Oxygen, I too have some fit issues and that is primarily due to the physical shape and design of the IEM itself. Its housing gets in the way of my Tragus (a physical part of the ear) which was my main source of discomfort, followed by the relatively shorter nozzle which can be solved by tip rolling. Although it is not a deal breaker, it certainly took off some points in this region and of course, shorter listening sessions due to how my ears gets physically tired from wearing these for longer periods. I would even classify this issue as the infamous achilles heel of the Tanchjim Oxygen which you willl see in many other reviews as well.

Sound (Overall Score: 8.5/10)

I find the Oxygen to be one of the better tuned IEMs that is somewhat harman-ish, having a natural presentation, an above average soundstage as well as accurate imaging capabilities really impressed me whenever I listen to them.


Sources used

- Ibasso DX120

- IPhone XR

- Atom DAC and AMP

Music and Albums, I listened to

- Alan Walker

- Billie Eilish – When we all fall asleep, where do we go?

- Tchaikovsky 1812 Overture

- Cigarettes After Sex

- One Republic – Dreaming Out Loud

- Kodaline

- Keane – Fears and Hopes

- Nino Rota – The Godfather OST

- Fedde Le Grand – Cinematic


- Halo 2 OST

- Halo 1 OST

- Czardas

- Lauv

- Scary Pockets

- Hans Zimmer

- Aladdin OST

Bass (Score: 8.5/10)

You can really feel the sub bass rumbling away on the Oxygen, giving that deep baseline that creates that feeling of being “filled” and not lacking in any way. Mid bass is also well articulated, punches and hits are impactful and agile at the same time. Listening to “Halo 2 OST”, drums are bass guitars really shine on the Oxygen where there aren’t any bass bleed, good punch and rumble that goes well with epic wartime genres. The Oxygen’s bass performance (details and separation) is impeccable, and I really enjoyed listening to it! Good job Tanchjim!

Mids (Score: 8.0/10)

The mids on the Oxygen doesn’t sound recessed or whatsoever, vocals still sound natural and spacious in the sense that they don’t sound distant but having that panorama effect. I would like to point out the Oxygen’s attention to detail here which might make it sound slightly sterile. Another plus point that really made the Oxygen an absolute joy to listen to is partly due to a relatively balanced upper-midrange gain which unlike many other offerings, does not have an overly emphasised pinna gain that makes it overly shouty. Again, it is a matter of preference, but it is one of the traits I appreciate on the Oxygen.

Treble (Score: 8.5/10)

Treble performance is applaudable as well as it possesses great extension, well refined as well as an airy presentation. I did not detect any sibilance nor harshness in this region, but I do feel that its attention to detail tires me out after an hour or so. Not really a con but just my thoughts to you readers that may help you understanding more about the Oxygen. I would classify its treble as energetic, detailed and refined that will satisfy most audiophiles’ cravings for treble.



The Oxygen nailed most areas right and on top of that, they have an impressive soundstage and imaging capabilities that you can find in higher priced offerings. Tonality and balance wise they do sound balanced and doesn’t sound too skewed to either ends. Timbre wise I do feel that brass instruments especially trumpets may sound too forward sometimes and hence unnatural when listening to “The Godfather OST”. To sum it up, it is one of the best single dynamic driver IEMs that I heard so far.


Vs Tanchjim Hana


Although the Hana resembles much like the Oxygen, it does sound brighter in its upper midrange and hence more likely to cause fatigue after longer listening periods. Although the Hana is significantly more affordable, I would prefer the Oxygen purely due to sonic preferences and a more robust tuning. The Hana is no slouch here in terms of other sonic attributes, but I do prefer a less fatiguing upper midrange which the Oxygen has which explains my choice here.

Vs Sony MDR EX800ST


Against one of my favourites, the EX800ST does have a much better fit, causing much lesser discomfort as compared to the Oxygen. The lows are not as refined on the EX800STs, but they are very competent in terms of tonality and linearity as compared to the Oxygen. The mids of the EX800ST are relatively more forward and sounds more accurate and detailed in its midrange/vocal’s capabilities as compared to the Oxygen. The Oxygen does beat the Sonys by a mile in its treble, having more extension and sounds way more refined/less grainy as compared to the EX800ST.

I find myself stuck in deciding where do I lean towards between the Oxygen and the EX800ST as I much prefer the flat tuning of the EX800ST but at the same time an adoration for the treble of the Oxygen. To summarise, I would prefer the EX800ST due to fit issues but at the same time, I would disagree with myself because of how well the Oxygen sounds.



In conclusion, although much pricier as compared to the Hana, the “YIN” manages to hold its ground and maintain its status of equals in terms of price to performance with the Oxygen being better tuned as compared to the Hana. The Tanchjim Oxygen was truly an enjoyable experience with good sonic capabilities and versatility that can satisfy most critical listeners and handle most genres but only to a fault in its fit issues where it causes some discomfort. If you can overcome the fitting problem, you might be looking at a winner here with great packaging, build and sound which sets many other IEM makers to shame.
Thanks for your review! really like my Tanchjim Oxygen, cables are getto though.. replacement cable of Tanchjim is really great instead!.. after a year or so.. thinking about to ereplace them by the Penon Serial:D.. realy curious... to listen to those.. :relaxed:
Thanks for your review! really like my Tanchjim Oxygen, cables are ghetto though.. replacement cable of Tanchjim is really great instead!.. after a year or so.. thinking about to ereplace them by the Penon Serial:D.. really curious... to listen to those.. :ksc75smile::relaxed:


Member of the Trade: RikuBuds
Pros: Stunning Female vocals quality
Treble extension and air
Bass quality
Instrument separation
Very clean and natural
Cons: Not that versatile due to sharp electric guitars (rock/metal) and not very fun for bass-focused songs (Trance, EDM, Hip-hop)
Male vocals not on the same level as the female (quantity and quality)
Short nozzle can be a problem for some
Treble can be a bit sharp
Bad stock cables

Disclaimer: I bought this at my own expense during the 2020 august sale for 180 usd

Price: 270 usd (non-sale, will judge it at it´s normal price)


Diaphragm: carbon

Frequency range: 10Hz — 40kHz

Impedance: 32Ω

Sensitivity: 110dB

Distortion: <0.2%

Noise reduction: 37db



S/M/L wide bore silicone tips

S/M/L narrow bore silicone tips

Black cable with-mic

Silver cable no-mic

Tanchjim emblem

Carry case

Replacement filters



Cables: Both cables are pretty bad both in measurements (mic = 0.43 and no-mic = 53) and in build quality. Plastic connectors at the 2pin, metal for the divider and 3,5mm connector. Non-working chin-slider for the no-mic cable. They are quite thin too, recommend switching to a 3rd party cable. Wished they sent just 1 higher quality cable instead of 2 bad ones.







Build: Very high-quality build with stainless steel. Feels solid and compact. The nozzle has a lip and a cloth mesh. The 2pin connector is recessed so that might cause some cables to not fit it, if the 2pin isn’t protruded.

Fit: I have no problems with the fit, but It is a short nozzle so that might be a problem for some.

Comfort: Pretty comfortable for me, it isn’t very big or small. It is pretty cold when you first put them in after a while though.

Isolation: Average isolation, it does cover most of my ear but there is a vent.

Setup: Ibasso DX160 (low gain, volume around 36), Faaeal litz copper cable, Final audio Type E LL tips

Lows: Low quantity (if the song has bass, you will get bass if not then you get no bass, but overall, on the lower side) but high quality. Overall, it is on the tighter and faster side with good texture and good extension so it is a clean bass. Sub and mid-bass are pretty even.

Mid-bass: Metallica – fight fire with fire (01:11-01:52), very clean due to the speed and tightness, but lacking in quantity and texture. The (02:55-03:01) section with the chopper sounds very detailed and clean.

Hiroyuki Sawano – Pretenders (01:18-01:47), tight and fast so it is very clean, texture also feels very good but needs more quantity.

Sub-bass: Djuro – Drop that bass (01:15-01:30), Extends very low but needs more rumble. The punch is pretty tight, fast and textured but needs more quantity.

Will Sparks – Sick like that (03:08-03:22), clean and powerful but needs a bit more texture along with some more speed/tightness.

Mids: Female vocals are extremely natural and very clean (although they can be sharp and sibilant on some tracks), very forward too. Male vocals are not on the same level both in quality and quality, since there is some lack of warmth that makes it less natural but still very clean and detailed.

Female-vocals: Hiroyuki Sawano – OldToday (01:25-01:52), very clean/detailed and sounds extremely natural due to the tonality (not too bright or too warm and note weight is very good for it).

Yuki Hayashi – MightU (01:58-02:55), Same as on OldToday, these tracks on the oxygen sounds amazing.

Evanescence – Bring me to life (01:18-01:35), sharp vocals and sibilant.

Hiroyuki Sawano – Crescent (02:07-02:26), sharp vocals and sibilant.

Male-vocals: Hiroyuki Sawano – Pretenders (00:57-01:17), Very clean/detailed but it is a bit too bright for the vocals and lacking some warmth although the note weight suits it well.

Hiroyuki Sawano – Scapegoat (00:57-01:17), Same as above, but this one lacks even more warmth and also some thickness too.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), the electric guitars are very sharp.

Deuce – America (03:03-03:16), too bright and shouty.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), both the cellos/violins are very detailed and textured, but the violins are a bit more natural sounding due to the tonality while the cellos lack a bit warmth.

Hiroyuki Sawano &Z (02:18-02:57), very natural and detailed and cymbals are very clear.

Soundstage: Extremely wide soundstage and depth is also very impressive.

Tonality: Bright-neutral and exceptional timbre for the acoustic instruments like pianos, guitars and violins however warmer instruments like cellos are bottlenecked by the tonality being too bright for them. And electric guitars tend to be sharp, especially on rock/metal tracks.

Details: Extremely detailed.

Instrument Separation: Separation is extremely good but imaging is exceptional.

Music: For the most part Hiroyuki Sawano songs aren’t that good for the oxygen due to it lacking some bass quantity for his songs. The exception to that is his live albums, where the bass texture, timbre, soundstage, imaging/separation and clean sound matches extremely good for it.

Songs that highlight the IEM:

Good genres: Acoustic songs, OST, orchestral, Live

Bad genres: EDM (not enough bass quantity and rumble), Hip-hop (too bright and not enough bass quantity), R&B (too bright and not enough bass quantity), Trance (too forward female vocals and not enough bass quantity), (rock/metal can have sharp electric guitars but otherwise no problem)


IEM: Tanchjim Hana

Djuro – Drop that bass (01:15-01:30), Extremely similar but a tiny bit lower extension in the Oxygen and also overall a bit cleaner sounding (but it is very close and is just splitting hairs).

Hiroyuki Sawano – Pretenders (01:18-01:47), Same on both, no difference.

Metallica – fight fire with fire (01:11-01:52), Sam on both, no difference.

Mids: Hiroyuki Sawano – OldToday (01:25-01:52), Vocals are a bit brighter and also more fatiguing on the Hana, so the oxygen sounds a bit more natural.

Evanescence – Bring me to life (01:18-01:35), a bit sharper on the Hana.

Hiroyuki Sawano – Scapegoat (00:57-01:17), more detailed and cleaner on the Oxygen, sounds a tiny bit warmer on the Hana.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), Much sharper electric guitars on the Hana.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), The cellos are equal but the violins are much cleaner and tonally correct on the oxygen, the oxygen has better treble extension and sounds airier.

Hiroyuki Sawano &Z (02:18-02:57), Very similar but less sharp on the oxygen and a bit more detailed.

Technicalities: Shiro Sagisu – Hundred years war (02:24-02:57), extremely similar but a bit more detailed and better instrument separation along with timbre (due to it being too sharp on the Hana). Soundstage is similar.

Overall: The oxygen is overall a more refined sounding iem and while both are on the brighter side and sometimes fatiguing, the oxygen isn’t as sharp as the Hana is.

IEM: Moondrop Blessing 2

Djuro – Drop that bass (01:15-01:30), extension and rumble are very similar but is much tighter and a bit faster and a bit more texture on the B2. Quantity is a bit higher on the Oxygen.

Hiroyuki Sawano – Pretenders (01:18-01:47), quite a bit more quantity and also more textured on the Oxygen but is tighter and faster on the B2.

Metallica – fight fire with fire (01:11-01:52), tighter and faster on the B2 but more quantity and texture on the Oxygen. The individual bass strikes are more easily heard in the Oxygen since the B2 has way too little bass quantity here.

Mids: Hiroyuki Sawano – OldToday (01:25-01:52), a bit more detailed and cleaner on the B2, but much more natural on the oxygen. The B2 with it´s BA´s gives it´s timbre some more “BA flavor” so it sounds unnatural in comparison.

Evanescence – Bring me to life (01:18-01:35), a bit sharper on the B2.

Hiroyuki Sawano – Scapegoat (00:57-01:17), a bit more detailed and cleaner on the B2, but much more natural on the oxygen due to it being a bit warmer and thicker.

Treble: Linkin Park – Shadow of the Day (03:24-03:42), both have sharp electric guitars.

Hiroyuki Sawano – Lose (string version) (01:22-01:59), a bit more textured cellos on the B2 and overall a bit more detailed on it. But the violins are much more natural due to the timbre. Similar treble extension and air in both.

Hiroyuki Sawano &Z (02:18-02:57), a bit more detailed and cleaner but more natural on the Oxygen.

Technicalities: Shiro Sagisu – Hundred years war (02:24-02:57), soundstage is a bit wider on the B2 but is a bit deeper on the Oxygen. Details and instrument separation are better on the B2. But timbre is much better on the Oxygen and much more natural overall.

Overall: Bass is a tie with the Sub-bass being better on the B2 and mid-bass better on the Oxygen. Mids and treble sounds more natural on the Oxygen while it is a bit more detailed and cleaner on the B2. The technicalities on the B2 are one step above the oxygen (except the timbre).

But If you want a clean but natural iem I would recommend the Oxygen over the B2, but if you want as clean and detailed as possible then the B2 could be the better choice (at the sacrifice of naturality and a much bigger physical size).

Conclusion: Very good iem with a very clean but not boring signature and exceptional technicalities amongst the single DD´s I have heard. For the genres that the Oxygen is good for it is in its own league and while it does have genres it isn’t very suited for (not very versatile) they aren’t exactly terrible and it can play them, just that there are other iems that will satisfy you more in those genres. Thanks for reading.

Ranking: S

Reference/test songs:

@TEKKU No comparison at all. The Oxygen already sounds more natural and therefore better for me than the Blessing 2 and the Blessing 2 is better than the KXXS in almost every way.
@RikudouGoku Bro does the Oxygen have reverse polarity? Read that somewhere, so maybe if we wanna use aftermarket cables with it, they might need to be reversed (ie have to get standard sets without ear hooks or angled connections)?


New Head-Fier
Pros: technically and tonally excellent IEM
open, mature sound, with very good imaging and transparency
HARMAN curve
Cons: HARMAN curve
seldom demanding
could use a little more sophistication sometimes
Rating: 9
Sound: 8.8

Am I an audiophile? I think that's in the eye of the beholder and depends mainly on who I compare myself with. Compared to my girlfriend, I am audiophile to the power of 10, because she is happy if music sounds out of her headphones at all, no matter in which way. Of course, I assume here that there is simply no comparison and, moreover, no will to classify what is heard in terms of sound. If I now compare myself with someone who is always striving to take his audio pleasure into new spheres through constant expansions, detailed adjustments and connections, which is usually accompanied by record-breaking sums of money, then I am again small with a hat on. Likewise, I wouldn't claim to have particularly analytical ears, but a broader musical understanding and the gift of being able to identify and compare even subtle differences.

What am I getting at? The HARMAN curve reflects, among other things, an "ideal" signature, which is supposed to do justice to the majority of the music consuming population, so it can be called mainstream.
So am I a mainstream consumer when it comes to sound reproduction? I think so and I stand by it. What distinguishes me, however, is the fact that I look beyond my own nose, what still exists and what might broaden my preferences, or even change/adapt them.
According to this, the TANCHJIM OXYGEN should be the jackpot for me, but
did he really?


A bit the QXYGEN reminds me of some 64 AUDIO models, concerning the rough shape. I like this simple design very much, also in terms of comfort.
The IEM name engraved on the full metal case (left) and the company logo (right) are of course a matter of taste, but I like this design. Apart from that, the faceplate is ground and therefore matt, only the engravings are "polished" and therefore stand out. The OXYGEN is also available in black.

As far as the workmanship is concerned, TANCHJIM cannot be blamed at all. Valuable, robust, stylish and above all focused more on the usability than on abstract ear warmers.

The scope of delivery is quite lavish, with a selection of silicone tips, two 2-pin cables (copper and silver, I like the silver one better haptically, but it doesn't have a micro), a hardcase and a golden small plate with the company logo. The whole thing comes in a nice square package.

The isolation is ok, but it needs music to be able to really isolate yourself from the outside world.


The good Mr. HARMAN has added his mustard here and so well that I would say that the OXYGEN hits the curve except for slight deviations and to the same extent, as for example the Moondrop KXXS, or STARFIELD, as well as the KANAS PRO, which was my favorite single dynamic IEM with Harman style until now. Was, because the OXYGEN is for me one more small upgrade and has conquered my HARMAN-infested heart.
So, enough with HARMAN, because even if I would call myself a mainstreamer, I don't agree 100% with the curve (which is always adjusted)

Let's get straight to what the OXYGEN does really well and that is the bass. Plenty of sub-bass level without neglecting the mid-bass, respectively there is a slight focus, which is a bit contradictory to HARMAN. In the upper bass it drops a bit, with a smooth transition to the midrange. The bass has punch, body and is also noticeable when the track delivers it. Due to the choice of drivers the dynamics are also a clear advantage and one never has the feeling that there is a lack of bass, but also not that it is too much. Just right for me, to the point and naturally. Subjectively, I find hardly any tonal errors in this area and also overall with the OXYGEN. The bass doesn't steal anyone's thunder, but doesn't put itself under a bushel either, but it could create a bit more pressure.

When talking about the HARMAN curve, the somewhat brighter tuning in the mids and also the accentuation of some instruments and partly the voices are sometimes "criticized", which can become unpleasant in the worst case. Well, the OXYGEN can't be denied this, but the question is also how the driver handles it technically and I find that this bothers me much more, for example with the STARFIELD. The OXYGEN gets by with the same signature with less negative hardness and sounds more relaxed, despite the same tuning. I find voices on the OXYGEN absolutely correct in tone, even if they can seldom be a bit demanding. Here one should have the volume in mind.
The voices are placed in front of the mix, but in the panorama they are wonderfully enclosed by the instruments, with a realistic separation. The mids manage to combine lightness, volume and naturalness with a slight bright alignment, which makes the OXYGEN appear very airy and spatial. This all sounds very positive, but through the Pink Glasses I can still see the somewhat too researched upper mids and I would like to exchange some of the relaxedness for a little more assertiveness of the lower mids.

The highs are very resolving and transparent, but can tolerate and forgive weaker sources without losing detail and naturalness. Nevertheless, I'd like to go a bit more directly to the point here, even though I appreciate the smooth but competent manner just as much. I think in the high frequencies most minds are divided and it is always difficult to make everyone happy. Before I have to take the in-ear out again after 5 minutes with an earache, but I can imagine that I've heard every micro detail, I prefer to swim in more relaxed waters and accept a couple of deductions. Please don't stone me now, I am also aware through my own experiences that a high resolution high tone is not immediately accompanied by earache and migraine, but here one quickly finds oneself in a completely different price range. The highs perform extremely well for their class, don't hide anything and surprise you with fine micro details every now and then.

Concerning imaging I am really impressed. Everything seems to harmonise perfectly and to build up on top of each other, side by side and one behind the other, with enough space in between to easily locate and focus on even single details.


The OXYGEN is the first IEM I was allowed to hear from TANCHJIM and even though I approached the sound with many expectations through the tuning I had heard before, I was not disappointed despite the weaknesses I was just as aware of.
Now, what would I miss to my happiness if we took the HARMAN curve as a reference? Well, maybe a bit more warmth, fuller lower and tamed upper mids, and a My more definition in the trebles. But these are my own preferences and also when it comes to OXYGEN grumbling on a high level. Who loves the HARMAN CURE will also love the OXYGEN and with it you get one of the best single dynamic IEMs with this signature on the market.
Even though TANCHJIM is a bit higher priced than MOONDROP with their comparable models, I think that with the OXYGEN you get a small but nice upgrade in terms of sound and technology. I guess at school you would have been scratched close to 1- with the OXYGEN, but in the end you'll be happy to get a well-deserved 2+ in terms of sound!


Thanks to OARDIO for the review unit.

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Reviewer at Headphonesty
Pros: Good, clean packaging
- Good, clean design
- Lightweight and durable
- Pleasing, inoffensive tuning
- Sub-bass response
- Mids tuning and timbre
- Excellent imaging capability
Cons: Sparse ear tips
- Shells prone to scratches
- Short nozzles, needs tip-rolling for best fit
- Poor isolation
- Bass lacks slam and definition
- Recessed upper bass and lower mids
- Rolled-off, overly smooth treble
- Overall detail and transparency
- Small soundstage
We present an earphone with a peer-reviewed sound signature that should by right, please everyone. With the age of research comes the Harman tuning, and the Tanchjim Oxygen is one of the fruits of this endeavor.

Air. Water. Food. Earphones. The universe is pretty clear about what is absolutely needed for living organisms to survive, and has given warning signs should your life be threatened. We have come so far and lived so long because we react to thirst, hunger, breathlessness, and deafening silence. The absence of music just worries me to death, you know?

Thankfully, many are on the same page as me. We slave all month to earn that paycheck and spend lavishly on food, beverages and in-ear monitors (IEMs). Luckily the air is free, but not so fast. Tanchjim likes to think that their greatest creation, dubbed the Oxygen, is as essential as air itself.

But who are they? Tanchjim (probably pronounced “thanks Jim”) is a Chinese company formed in 2015 and specialize in IEMs. They create their IEMs based on two tenets, that is cleanness of build and sound quality. To achieve the former, their IEMs are packed in neat, minimalist boxes. For the latter, they turn to the Harman Target Response Curve.

The Harman Target Response Curve is, in simple terms, a very educated guess at an ideal sound signature that will please most people. Conducted by Dr. Sean Olive and Todd Welti of Harman International, the research produced two target curves, one for headphones and the other for IEMs, as a guide for manufacturers to build better transducers. Products that follow either curve are deemed Harman-neutral.


Pristine and pure, just like an ad for whitening cream.

Today we look at Tanchjim’s flagship IEM, the Oxygen. Using a single 9.2mm graphene dynamic driver contained in a stainless steel shell, this Harman-neutral IEM represents the fulfilment of Tanchjim’s philosophy. A simple and pure IEM made to please your eyes and ears. They definitely turn heads, but will they move mountains?

The Oxygen is currently available at Apos Audio. I would like to thank Apos for the review sample and tremendously fast shipping. It has been a pleasure dealing with them.

This review was first featured in Headphonesty.

Equipment Used:

  1. Sony NW-WM1A “K” Modded, FW 2.0
  1. Tanchjim Oxygen
  2. FiiO FH5
  3. FiiO FA7
  1. Aaron Neville – Warm Your Heart
  2. Celine Dion – The Colour of my Love
  3. Fleetwood Mac – Tango in the Night
  4. Macklemore & Ryan Lewis – The Heist
  5. Queen – Greatest Hits I
  6. Roxette – A Collection of Roxette Hits!
  7. Sade – Soldier of Love
  8. Taylor Swift – Lover
  9. Tears for Fears – Songs from the Big Chair
  10. The Eagles – Hell Freezes Over

Technical Specifications
  • Driver: 9.2mm graphene dynamic driver
  • Sensitivity: 110dB/mW
  • Impedance: 32Ω
  • Frequency Response: 10Hz – 40kHz
  • Connector: 2pin 0.78mm
  • Plug: 3.5mm gold-plated straight plug
  • Cable Length: 1.2m
  • Cable Material: Silver-plated oxygen-free copper (OFC)


Cubes are awesome. More things should come in cubes.

Packaging and Accessories

Tanchjim loves hygiene. Besides (probably) washing their hands before and after assembling their prized IEMs, a lot of thought was given to the retail package. To project the image of cleanliness, who better to draw inspiration from than the masters of packaging, Apple? The gray Oxygen box resembles iPods of old, with few words, big graphics and catchy names (except Tanchjim, can’t help you there).

A full unboxing and uncovering of the layers reveals a moderately well-stocked accessory set. They are:
  • 6 pairs of silicone ear tips in assorted sizes
  • Zippered carry case
  • A silver-plated OFC cable
  • A microphone cable
  • A metal sticker
  • 20 nozzle filters
  • Manual and warranty information
I’m scratching my head at the metal sticker too. The stock cable is lightweight and attractive, with compact and svelte splitters and connectors that project minimalism at every turn. I would prefer a more premium, sturdier cable, but then again that’s not their design philosophy. The metal sticker is probably a loyalty pledge, while the nozzle filters are welcome if your ears are waxy and well, unhygienic.

The carry case is small, and can only carry the essentials, just the Oxygen and the stock cable. The ear tips selection is sparse, and only in silicone. Unlike the glorious tip buffet of FiiO models, if none of the stock tips fit you well, you’ll have to scour for third-party. The mic cable wasn’t of use to me. I’d have preferred a Bluetooth cable since the industry is squarely headed in that direction.


Gotta say, the reflections all over make this a b*tch to photograph.

Design and Build Quality

The Oxygen has a simple, clean (there’s that word again) design, with stainless steel earpieces and sandblasted faceplates. The Tanchjim logo adorns the right faceplate while the word Oxygen is in the left. The shells are medium-sized with rounded-off edges, projecting a sense of calm and understated class. Or perhaps, the sterility of a laboratory.

As for build, the Oxygen is made of food-grade 304 stainless steel with a mirrored finish, like the Tin Hifi P1. Both designers probably had a eureka moment while lunching. The shells are solid and well-built, with uniform smoothness throughout, even at the seams. This is a design that will please many, and should last a long time.

After a few months of use though, the flawless shells invited scratches and smudges, as evidenced in the photography. This is despite normal usage and keeping them in the carry-case when not in use. I don’t keep pets or rabid animals in the house either, just my family lol. So the Oxygen is decidedly high-maintenance, like the ex-girlfriend who can tell fake Chanel.

Fit, Isolation and Comfort

The Oxygen’s all-metal build, thankfully, has rounded edges throughout, so don’t worry about sharp edges poking where it shouldn’t be hehe. The earpieces slide into my ears without any fuss, although the short nozzles might prove worrisome. The ear tips provided are wide-bore, short and stubby, and, compounded by the short nozzles, is difficult to maintain a good seal.

The stock tips seal well when I’m seated and immobile, but when walking around the Oxygen tends to fall off my ears because of the poor seal. At moments like these, I turn to my Final Audio Type-E ear tips which provide maximum comfort and seal. I sound like an ad you can’t click away, but these tips really work for me.

Isolation is not very good. Not only do you have to scuffle and tussle with the fit, the vented design of the Oxygen works against you too. This is not an IEM to bring outdoors unless you like the “ambient” function of true wireless earbuds. A lot of outside noise is heard, and you can see (hear?) why the Oxygen is mainly an IEM that stays indoors.


In an alternate universe, ladies would gift these to you as jewelry.

Sound Quality

For people who haven’t quite gotten the gist of reading a frequency response graph (that would include me), don’t despair, I have a whole section and plenty of words to describe the sound of these babies.

Overall Sound Signature

Transducers that follow the Harman target curve are called Harman-neutral, as is the case with the Oxygen. But what does that mean actually? The adjustments to the sound signature include an elevated sub-bass and midbass, neutrally-placed mids, and raised upper mids to lower treble, aiming to deliver both detail levels and fun.
So if every IEM was Harman-neutral, would they all sound the same? Not necessarily so. The Harman curve only tells you the amounts of bass, mids, and treble in relation to each other. Other parameters like tone and timbre, soundstage size, imaging accuracy, and note characteristics cannot be measured. It also depends on the driver among other things.

For the Oxygen, they’ve decided to go full Sade. Like her biggest hit “Smooth Operator”, the Oxygen aims to project smoothness and relaxation at every turn. Like drinking a quality smoothie, not those poorly-made ones with uncrushed ice at the bottom, which will land you in the hospital if you took a hard sip.

The inherent weakness among Harman-tuned IEMs are, manufacturers willingly follow a tuning template that should please most people. But when you think about it, does anything really? So critics of the Harman curve say the tuning follows an overly safe, inoffensive route, sort of like vanilla ice cream. It’s… nice, but hardly lands in anyone’s favorite lists, yeah? But let’s not put the Oxygen on the chopping block just yet.

Listening Conditions

Critical listening was done after 100 hours of burn-in, breaking down the thick and rigid graphene dynamic driver and reducing it to a delectable, beefy stock. The transients are a tad faster after burn-in but it could just be my mind messing with me. The main review rig is Sony’s NW-WM1A Walkman modded by Project K, using the stock cable.


I fall for shiny objects, but my fingerprints say otherwise.


Speaking of vanilla ice cream, Oxygen’s sub-bass licks are tender, loving and gentle. Extension down below is excellent, with an audible thump and good rumble, like sitting on a massage chair who wants to get friendly. It’s not head-rattling nor overdone, which is nice. This is a well-behaved sub-bass that will please, surprise surprise, most people.

At the midbass, a mellow bloom lends warmth. Notes are rich and rounded, flowing from one to the next with good timbral accuracy. Attacks are smooth-edged and cut back on urgency, while decay takes its time. This is a warm, gooey and relaxed midbass that I wish would hit harder and faster. The slam isn’t satisfying enough, dynamics are subpar, and there is smearing in fast passages.

Moving up, the upper bass is de-emphasized, with a big scoop from here to the lower mids, which prevents bass bleed and increases airiness, but thins out the sound. The music seems uninvolved and lacks character, like drinking soup with too little salt. I want commitment and conviction! Overall, the sub-bass is worthy, and details and layering are decent, but the bass is let down by a weak punch and lean upper section.


Let’s start with the worst part of the mids, since there’s no escaping the specter of the upper bass to lower mids recession. The meat of the music may be in the mids, and here’s where it’s the boniest. The Oxygen renders male vocals, bass guitars and cellos with trepidation and hesitation, sounding reedy and nonchalant, and pushed back in terms of placement. This is the tardy kid of the signature.

From the middle mids, things get better, and finally, Oxygen gets his moment to shine. Your toes start tapping and jaw starts snapping, for the soul of the music is back. The center mids are so good they paper over the cracks and imperfections of the rest of the signature, sounding remarkably natural, organic and full-bodied.

Female vocals, guitars, and pianos sound enchanting and soulful, with a hint of speed. Notes are well-rounded and decay beautifully, imbuing a sense of air and fleet-footedness. This carries on into the upper mids, violins and brass instruments ring out with majestic bravado and supreme confidence. The timbre is spot-on and well-balanced, providing enough details to go with the euphony. The highlight of the Oxygen is here, and the mids alone are worth the price of admission, helping you forget about past transgressions.


Needs some heavy makeup to hide all the blemishes and shame.


This is where you might want to ask for your money back. Listening to the treble is like a trip to the dentist, or Sade’s second-biggest hit “Tooth Operator”. The notes have no bite nor urgency, like a meal of porridge after losing a few teeth. It’s overly smooth and inoffensive, providing just a bit of shimmer at times, but averse to risk and perhaps, rewards.

No doubt, timbre is still quite good, with a natural and realistic tone from the lower to middle treble. But with excitement levels akin to wearing socks with flip-flops, it’s hard to be aroused or enthused by the sonic equivalent of warm drinking water. It’s no surprise the treble leaves the party early too, as the extension levels fall short and the signature lacks airiness up top.

This is a treble tailor-made for mild-mannered people who veer on the safe side of everything, who dip their toes into the pool and return indoors. Some will find this agreeable, but for me, it’s an aid for curing insomnia. A good tone but devoid of transparency, air, details, and most of all, energy.

Soundstage and Imaging

Like Sade’s third-biggest hit “Booth Operator”, the Oxygen’s soundstage size felt boxed-in and intimate. It wasn’t impressive in terms of width, depth and height, providing an on-stage feel with the musicians surrounding you in a game of musical chairs. The music surrounds your head, sometimes entering it, providing little breathing space despite being named Oxygen.

Imaging and separation do much better. Anchored by the winsome mids which take centerstage, imaging cues are precise throughout the X and Y-axis. While the smearing in the midbass prevents a thoroughly clean and airy stage, the Oxygen does enough to immerse the listener in the music, aided by the small soundstage in fact. You feel like you’ve just booked a private, one-on-one session with your favorite musicians.


Frustrated with life in the spotlight, they make a hasty retreat.


FiiO FH5

At the gates, my $300 benchmark awaits. The FH5 has a detailed, exciting W-shaped signature that is the direct antithesis to the calm, smooth and if I may, bland Oxygen. I won’t pretend to be unbiased, because FH5 possesses one of my favorite tunings, and I’m struggling to reason why you should get the Oxygen when the FH5 is available for nearly the same price.

If we look at the sound characteristics, FiiO’s mid-tier hybrid has more visceral sub-bass, punchier and tighter midbass than the Oxygen. Crucially, the treble is crisper, airier and a magnitude more detailed. These are the most obvious changes, but what a glaring difference they make to the sound, injecting pace, rhythm, urgency and most of all, a sense of fun to the mix.

Looking at technical ability, the FH5 is more extended in both ends, with a sharper attack, swifter decay, and much better note definition and transparency across the board. The FH5 is clearer, hits harder, and handles music with more finesse. The Oxygen is made to eat humble pie and like it.

The Oxygen doesn’t go home empty-handed and get some nice party gifts. The mids are a tier above in terms of tone and timbre, while the imaging is more accurate. But mids alone can’t save the signature when the FH5 is obviously a better all-rounder. Their both shared weaknesses are the lower mids dip and a small soundstage, but taken as a whole, consider Oxygen’s butt well and truly owned.


Out in the wild, their prospects of survival aren’t glittery.

FiiO FA7

The previous battle was inexplicably one-sided, but what about lesser opponents? The FA7 takes a similar route as the Oxygen, going for a warm, luscious sound that is gentle on the ears and high on emotion. Both IEMs weave some mondo mids magic to entice and enchant our gullible hearts and wallets, so this should be on more of an equal footing.

So across a warm climate and template, they are evenly-matched. Oxygen boasts a more robust, thumpy sub-bass, chugging away at the bottom while FA7 is better-extended and more energetic in the treble region. FA7’s mids are more liquid and dense, like thick maple syrup, but Oxygen manages the same arresting tone while sounding more nimble and airy.

The slugfest continues and spills all over the arena. FA7 has a bigger soundstage but Oxygen has sharper imaging. Oxygen has a more solid build but FA7’s accessory package is better equipped. Their main weaknesses, Oxygen’s lower mids dip and FA7’s midbass hump are equally infuriating, robbing both IEMs of greatness.

This is a battle of the flawed titans with no clear winner. That being said, both are equally suitable for prolonged, non-fatiguing listening sessions with beautiful mids, so pick your poison.


Nothing rhymes with oxygen, I’ve tried, and was left flummoxed-ygen.

Final Words

Sometimes, all I need is the air that I breathe and to love you. The Harman target curve has the noble intention to elevate tuning expertise as a whole, by providing a usable blueprint for manufacturers to follow. It’s like publishing a recipe for a foolproof, fail-proof soup stock so nobody would ever have to make do with bad soup again.

Of course, recipes can be followed to the letter, or you can take several liberties with them and call them your own. Tanchjim chose to tune their flagship with a beautiful tone in mind, and for all intents and purposes, they’ve succeeded. The Oxygen has a tone to fall headfirst in love with. Even when taking into account its weaknesses, you have to admit, nothing is jarringly wrong with the tuning.

Yes, you can pepper the sound with more excitement, the bass could be meatier and more wholesome, but given the chance, the Oxygen stands on its own as a well-implemented take on the Harman tuning. And this, my friends, is just the beginning. With more and more companies tweaking and releasing their own version of the Harman signature, this might just be the new mainstream.
FA7 vs Oxygen.

Wut? FA7 is one of the worst IEMs I've listened to, it's a bloat fest and has technical performance comparable to sub $50 IEMs at best.

Oxygen runs circles around the FA7, it's not even remotely close.


Reviewer at Twister6
Pros: Great Sound Quality - Harman-ish Tuning.
- Comfortable natural sound signature.
- Good deep bass, clear mids with smooth but defined treble.
- Tonality.
- Good resolution for a single dynamic driver.
- Build Quality.
- Good packaging.
Cons: Fit isn't the best yet stays in your ears comfortably.
- A single better cable could've been provided instead of two different cables.
My background- I am a professional musician, producer and an audio engineer by education, with experience in the performing, recording and pro-audio industry. I test products on a technical and musical level, and try to write reviews as simple as possible from a music fan's perspective.

Disclaimer – The sample was provided for a test and review. I am not affiliated with the company and write this review with my best unbiased opinion regardless of how the review turns out.

Genre preferences- I majorly listen to rock, acoustic, pop and metal genres and occasionally checkout EDM music which is doing the rounds on the radio and charts.

About the product - Tanchjim Oxygen is a single 10mm dynamic driver in-ear monitor which sells for around $270. It is available in 2 color options, silver and black.

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You can buy the Tanchjim Oxygen from Shenzhen Audio

  1. Driver Tech - 10mm Dynamic Driver
  2. Diaphragm Type: Carbon Nanotube Diaphragm
  3. Frequency response: 10–40,000 Hz
  4. Sensitivity: 110 dB
  5. Impedance: 32 ohms
  6. Plug: 1/8 in (3.5 mm) Gold-Plated Line Plug
  7. Cables: 1.2m OFC Silver Plated Cable Without Mic & 1.2m OFC Cable With Mic
  8. Interface:0.78mm 2Pin
Included in the box-
  1. Oxygen
  2. 2 Cables – One with mic and one without.
  3. Silicone eartips – 7 pairs
  4. Carry Case
  5. Metal sticker with brand name and logo
  6. Warranty card, counterfeit protection card and short user guide

Build Quality – Tanchjim gave me choice of color and I chose black. The shells are made of metal and are finished very well. One shell spots their logo and the other spots the name ‘Oxygen’. The seam between the faceplate and the shell is done perfectly too. The color plating is so good that there isn’t a scratch on the shell or the nozzle in my 2 month’s usage. Or maybe I haven’t used them in extreme conditions enough. Haha

They’re one of the few companies who include 2 cables in this price range, one with mic and one without. But sadly, both the cables don’t live up to the premium feel of the package and IEMs. I would’ve been happier if they included a higher quality cable as stock in the package even if they had to chuck the mic cable to cut costs.

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Tanchjim Upgrade Cable – Tanchjim however sent me their upgrade cable too and I love it! The wire is 5N single crystal copper. It is covered in a black cloth sheath which looks very good and gives me an impression of being solidly built. The connectors and jack are of good quality too. This cable conducts better than the stock and is definitely an upgrade.


Fit and Comfort – Oxygen’s shells are extremely light to be comfortably worn for long periods but if you’re looking for a snug fit where the nozzle goes in and the rest of the shell fills up the concha, sadly this is where the Oxygen falls short. As some people reported, the nozzles really are short and stout. It would’ve been great if they had designed it to be a little bit longer. Nevertheless, the shells sit in my ear really well and don’t fall out if my shake my head heavily. Most of the time when I’m wearing it, I don’t even know they are there.


Sound Analysis – Tanchjim has tuned Oxygen very well along the lines of Harman Target curve and ensured that the bass goes deep, mids are transparent and treble is sparkly and clear. It has a very clean character with very good amount of details for a single dynamic driver.

Bass – Oxygen being a dynamic driver re-creates the bass really well. The sub-bass has good reach and mid-bass is tasteful, but in no way does it dominate the track. It’s very well balanced compared to the rest of the frequency spectrum yet very clear, crisp and impactful. Notes have good authority and are distinguishable even in heavy layered music. You can hear and feel the bass rumble in songs like Porcupine Tree’s ‘The Start of Something Beautiful’ and ‘Halo’. It got me pretty excited about the song and I heard them in loop a couple of times.

Mids – If you’re familiar with Harman mids, you know how they look on a graph. Oxygen’s mid dip is very natural and makes lower mids sound very clear. This complements the clarity in the upper mids perfectly. The resolution is extremely good too. As a result, in heavily layered songs, snare body or lower registers of vocals never get shadowed by pads, mid bass or synths.
  • Deep vocals in songs like Coldplay’s ‘Another’s Arms’ and ‘Yes’ have good depth, clarity and sound upfront without getting lost in the mix.
  • Falsettos and higher range vocals in songs like Gavin James’ ‘Always’ and Maroon 5’s ‘Payphone’ always sound clear and crisp but never piercy.
  • Acoustic guitars have good string clarity and presence but never sound sharp.
  • Distortion guitars in songs like Breaking Benjamin’s ‘Diary of Jane’, Kanivool’s ‘Simple Boy’ and I Am Giant’s ‘Razor Wire Reality’ sound huge and have very good tonality, definition and clarity.
  • Kicks have good attack and snares have good body and depth.
Treble – In earphones with Harman style tuning, the treble can tend to sound a bit rolled off but the Oxygen portrays it quite well. Oxygen is not a dark sounding IEM at all. Treble character will probably please most with its naturalness. The treble supports the high mids very well giving guitars a good hint of airiness, snares have good stick attack and orchestral instruments have good sheen. There is no issue of sibilance at all. All in all, the treble is smooth, yet has good sheen, definition and clarity.

Soundstage, Imaging and Separation – Oxygen’s soundstage has good width and depth. Hard panned guitars sound open and wide, and reverb have good depth to give you a realistic experience. Imaging is on point, with instruments placed accurately throughout the space. Separation for a single dynamic driver is commendable.

Comparisons –
  • Tanchjim Oxygen vs Moondrop KXXS ($189) – Oxygen and KXXS are similar in terms of build and the choice of driver but differ more in sound. Both are made up of metal shells. Both are available is shiny silver finish but Oxygen is also available in Black (the one I have). In terms of sound, Oxygen sounds organic, nicely balanced and earthy (lifelike like listening to the song in a studio), whereas KXXS has similar qualities but sounds a bit more open, airy with a slightly thinner character.

    Bass and sub-bass in isolation are very similar. In order to gauge the quantity and quality, I listened to Hans Zimmer & James Newton Howard’s ‘Why so serious’ at the 3:26 mark over and over again. After back and forth about 20 times, I’m still unsure which has more sub-bass, ummm....maybe KXXS. Oxygen on the other hand presents slightly more mid-bass in songs like Porcupine Tree’s ‘.3’. Vocals sound earthy in the Oxygen but sparkly in the KXXS. High mids are a bit more present in KXXS so acoustics, hi-hats and orchestral instruments have a bit more presence in tracks. Snares also have slightly more stick attack and smack in KXXS whereas Oxygen again sounds more organic.

    Oxygen and KXXS are like brothers. Oxygen is the more mature brother whereas KXXS is the more adventurous and enthusiastic one. As for fit, KXXS fits much better than Oxygen but Oxygen has a lip for ear tips to stay in place.
  • Tanchjim Oxygen vs Tansio Mirai TSMR-3Pro ($220) – Oxygen and 3Pro have different tech inside where Oxygen has a dynamic driver and 3Pro has 3BAs. Oxygen has more bass presence whereas 3Pro has slightly fuller mids in comparison. As a result, 3Pro has more snare slam and sounds a bit warmer, more towards neutral. On the other hand, Oxygen portrays a cleaner mids character because of the Harman dip in the mids. 3Pro has a bit more 3kHz presence and as a result distortion guitars in bands like Periphery and Lamb of God sound a bit more present in the mix. Treble in both sounds natural and compliments higher mids very well. There is no sibilance in either IEMs.

  • Tanchjim Oxygen vs LZ A6 – A6 with its filters gives you more flexibility in tuning the sound signature. But considering LZ A6 with my favorite Red filter, I prefer Oxygen for its overall tonality, balance and character. A6 is energetically tuned with treble taking the lead whereas Oxygen in comparison sounds much better balanced and refined, targeting the Harman tuning.

Conclusion – Tanchjim deserves a pat on the back for tuning Oxygen. It is an excellent specimen of Harman tuning and is one of best sounding IEMs under $300. The build quality and packaging is great too. If only it had a better fit with shells being slightly bigger and the nozzles a bit longer, it would’ve been a perfect IEM that I would never want to part with ever in my life. Also, even though they include 2 cables in the package (one with mic), I wish they had chosen to include a single better-quality cable instead. Nevertheless, Tanchjim Oxygen is a very good IEM with great sound and I can recommend it for its sound and build quality, wholeheartedly!

Gear used for testing -
  1. Logic Pro X session with hi-res test tracks played through Universal Audio Apollo
  2. Macbook Pro
  3. Hiby R6 Pro
  4. Oneplus 7 Pro
You should, they're very good on short nozzle and doesn't bend as SpinFits tends to! Actually, getting them might be a challenge, I've got them directly from Azla. Maybe some local Asian's stores might sell them but some of them doesn't ship abroad (IDK where you are from...).
@iBo0m Okay cool! I'll keep an eye out for them. :)
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Reactions: iBo0m
Good luck! If you won't be lucky to find any, you can always try to get in touch with Azla directly and see :) They also sell "light" version which is available exclusively at Azla (maybe they started to export it to re-sellers by the time I got mine, IDK).


500+ Head-Fier
Pros: balanced tuning, highly resolving, fast, great build quality and finish
Cons: fit issues, cables should be better at this price point
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The Tanchjim Oxygen is an in-ear monitor with a single 10mm diamond-like carbon diaphragm dynamic driver per side. This review is based upon a retail unit purchased by me at list price for personal use from Linsoul Audio.

I have used the Tanchjim Oxygen with the following sources:

Windows 10 PC > JDS Labs The Element > Tanchjim Oxygen
Pixel 3 > Fiio BTR1K (Bluetooth Apt-X) > Tanchjim Oxygen
Windows 10 PC > Fiio BTR1K (USB-DAC) > Tanchjim Oxygen
Pixel 3 > Apple USB-C to 3.5mm dongle > Tanchjim Oxygen

I have tested these headphones with local FLAC and Spotify Premium.

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The Tanchjim Oxygen comes in a mid-sized grey cube-shaped package. The front panel of the slipcover bears a rendering of the IEM, as well as the model name, the Tanchjim logo, and manufacturer tagline “Feel more, Hear more.” The left- and right-side panels bear the Tanchjim logo and the model name, respectively. The back panel of the slipcover shows an exploded diagram of the IEMs, along with specifications and manufacturer contact information. This information is presented mostly in Chinese.
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Underneath the slipcover and a top lid removing the slipcover reveals a series of smaller overlapping boxes, the topmost containing the eartip selection, a warranty card, a card indicating how to attach the cable, a QC pass chit, an owner’s manual, and a set of 20 spare nozzle filters. There are two sets of dark grey silicone eartips, one set of short, wide bore tips (S, M, L) and one set of more typical eartips (S, 2xM, L).
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Underneath this top box is a mounting foam sheet holding the IEMs faceplate-up, and a box containing the zippered carry case. The carry case is on the small side, made of dark grey leather embossed with the Tanchjim logo in black. The carry case will fit the IEMs with either of the included cables, but if you use a bulkier braided aftermarket cable with the Oxygens you will likely need a larger carry case. The two included cables are stored underneath the foam mounting sheet.

The Tanchjim Oxygen’s housings are polished dark grey stainless-steel slabs in the shape of a heavily rounded right triangle. The machining and polish are impeccable. The left and right faceplates bear the model name and manufacturer’s logo in black. The standard .78mm 2-pin cable connections are flush with the housing on the forward-facing side of the IEM. “Tanchjim Oxygen” and “L/R” is written on the inner surface of the housing in silver. The forward-swept short nozzles protrude from the bottom corner of the housing. The serial number is written in silver around the nozzle of the right earpiece.

Each earpiece has two circular vents, one above the nozzle on the inner side of the housing, and one on the rear-facing side. There is no driver flex, but I did experience diaphragm popping upon first insert in the first day of using the Oxygens. This only occurred while using dual-flange eartips. The nozzles have substantial lips, which facilitated use with a wide variety of eartips.
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The 2-pin connections are snug and secure, but are slightly recessed, limiting alternative cable options. The mic’d cable is encased in a black rubbery sheath, while the OFC silver plated cable is enclosed within a clear plastic sheath. Both cables have straight 3.5mm terminations, use pre-formed plastic ear-guides, and have blue or red dots on the 2-pin housings to indicate left or right. The silver cable has a choker, but the mic’d cable does not. The silver-plated cable is flexible but does have minor microphonics. The mic’d cable is more microphonic than the silver-plated cable. Neither cable is prone to tangling. The pause control on the mic’d cable works as intended, but the +/- volume controls trigger an increase or decrease to maximum or minimum volume rather than a single volume step change. I did not have the opportunity to test mic call quality before writing this review.

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The Tanchjim Oxygen is intended to be worn cable-up only. The Oxygen has a shallow insertion depth and the housings are on the small side, but because the cross-section of the Oxygen is more aesthetic-focused than ergonomic I did experience some discomfort after prolonged wear over the course of several weeks.

Extensive tip rolling is essential. For me, getting a secure fit and a good seal was troublesome with any but the largest conventional silicone eartips. I settled on using Sony Hybrid type tips, which are made of a grippier material than most eartips. Double or triple flange eartips will also work. Noise isolation is average for a single dynamic driver design.

The Tanchjim Oxygen has a cool, neutral-ish tuning with an emphasis on presence, detail, and clarity.

The Oxygen has accurate, insistent bass. The well-extended sub-bass is slightly elevated compared to the mid-bass. The mid-bass is impactful yet precise and does not bleed into the lower mids at all. Bass comes across as textured despite the restrained presentation. There is some rumble but little slam. Bass articulation is lightning-quick.

The midrange tonality is dead neutral, and listeners coming from IEMs with a warmer tonality will likely find it cool. The lower mids are recessed compared to the upper mids, but male vocals are crystal clear. Both male and female vocals can overshadow instruments in the lower midrange. Female vocals are vibrant without being sibilant. There is enough presence to render detail and grit convincingly, but not so much that the IEMs are inherently harsh.

The treble is crisp and energetic with ample air and sparkle. Transients are very natural sounding. Resolution is outstanding but unforgiving to poorly recorded sources. Instrument separation is superb. Soundstage is small compared to hybrid or multi-BA designs but compares well to other single dynamic designs. The Oxygen is the first IEM I have heard that has “holographic” imaging.


My measurements were conducted with a Dayton iMM-6 microphone using a vinyl tubing coupler and a calibrated USB sound interface. The measurements use a compensation file derived from comparing my raw measurements with Crinacle’s published measurements. The measurements are presented with 1/24th smoothing. There is a resonant peak at 8k. Measurements above 10k are not reliable.

With a sensitivity of 110dB and an impedance of 32ohms, the Tanchjim Oxygen can be driven to comfortable listening volumes with a smartphone or dongle but will benefit from the additional headroom provided by a dedicated source if one wants to listen at high volumes. I did not notice hiss with any of my sources.

Tanchjim Oxygen [$270] vs Nicehck M6 (brass filter) [$94]
M6 vs Oxygen.jpg

The Oxygen has much more extended sub-bass. The Oxygen’s bass is faster, better articulated and is much less boomy. The M6 has more textured bass. The M6 has more slam than the Oxygen. Even with the brass filter, the M6 has more midbass bleed than the Oxygen.

The M6 has a warmer, less recessed lower midrange, and a more aggressive upper midrange. The M6 has more intimate midrange, while the Oxygen creates more space between the listener and vocals. The M6 is more prone to harshness and sibilance.

The M6’s lower treble is elevated compared to the Oxygen. The M6 has more sparkle but less air. The Oxygen has more realistic transients. The M6’s treble is splashy in comparison.

The Oxygen is more detailed and resolving. The M6 has a much larger soundstage. The Oxygen has better instrument separation and more precise imaging. The M6 is slightly easier to drive.

The Oxygen has a more premium unboxing experience and a greater variety of eartips. The Oxygen includes two cable variants and a higher quality case, but the case included with the M6 is larger. The M6 is tunable via swappable filters.

Tanchjim Oxygen [$270] vs Simgot EM1 [$60]
Oxygen vs EM1.jpg

Despite the price difference between the two, the Oxygen and the EM1 have similar frequency responses. The Simgot EM1 has slightly better sub-bass extension. The Oxygen’s bass is faster and better articulated.

The two IEMs are nearly identical in frequency response between 40hz and 4000hz, where after the EM1 exhibits a pronounced 5k peak. With that said, the EM1 has a warmer midrange tonality and a slightly brittle timbre compared to the Oxygen.

The Oxygen has more air than the EM1. The Oxygen is significantly more detailed and resolving.

The EM1 has a slightly wider soundstage, but the Oxygen has better imaging and much better instrument separation. The EM1 is easier to drive.

The Oxygen is more comfortable but the EM1 sits more securely in the ear. The EM1 has a venting issue that the Oxygen does not have. The EM1 has a more premium unboxing experience and a similar variety of included eartips but does not include a real zippered carry case. I prefer the braided cable that comes with the EM1 to either of the cables included with the Oxygen.

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The Tanchjim Oxygen is a lightning-quick, highly resolving IEM with outstanding instrument separation and imaging. However, the unboxing experience is underwhelming given the more premium packaging of IEMs which cost less than 1/3rd of the price of the Oxygen, and while the design and finish of the IEMs themselves are astonishing, the cables are disappointing at this price point. Commendable from a performance standpoint but not the best value in IEMs.


500+ Head-Fier
Pros: great bass texturing and reproduction, full bodied mids, accurate treble, wide stage, good fit
Cons: not found
Some time ago we’ve been reviewing Tanchjim single dynamic driver IEMs with the name that perfectly described its overall design and sound tonality — DARKSIDE. Those were bass-oriented with warm timbre, perfect look and excellent fit.


Recently, Tanchjim has released the new and more advanced model that inherits some of the best features of initial one and targets significantly higher price segment. This new model is called Oxygen and we believe that, again, this name should give us a clue about its design and sound characteristics: light and clear look, airy and transparent sound. By the end of this review we should be able to object or admit this statement. By the way, both models are doing very well in Japan, with lots of Tanchjim fans out there.


Tanchjim Oxygen technical specifications:
  • Type: dynamic driver IEMs
  • Dynamic driver: High performance dual chamber / dual brake
  • Diaphragm: carbon
  • Frequency range: 10Hz — 40kHz
  • Imdepance: 32Ω
  • Sensitivity: 110dB
  • Distortion: <0.2%
  • Noise reduction: 37db
  • Cable connectors: 2pin, 0.78mm
  • Color options: silver, black
  • Audio Cable: 1.2m, Sliver-plated OFC
  • Plug: 3.5mm gold-plated, straight
  • Smartphone cable: 1.2m, with inline mic and remote
  • Plug: 3.5mm, straight
Driver structure:


Other declared features:
  • Driver technique: Carbon nanotube dual-chamber / dual brake dynamic multi-tuning allows Oxygen to expose more details and show beautiful tone rendering
  • Process and materials:
    • The outer shells are hand-polished (right shell contains unique ID)
    • Each pair of headphones is unique due to hand-processing
    • 304 grade stainless steel ensures the safety of use and no irritation to skin
    • Nano-grade silver ion vacuum plating technology applied to 02 cavity helps to resist bacterial contamination

Packaging, design and materials:

Tanchjim Oxygen come in grey square box with only brand name and logo printed at the front. There is no outer cover as seen in DARKSIDE, neither there is any additional data or picture of the IEMs. Very minimalistic approach.


The innner box compartment is split into 3 layers: box with accessories at the top, soft foam retaining IEMs in the middle and another accesory box along with audio cable compartment at the bottom.


In fact, the contents of the box are quite rich:
  • Oxygen IEMs
  • audio cable for pure audio sources
  • audio cable with inline remote and mic for smartphones
  • 7 pairs of silicone eartips
  • Aluminum plate with brand name and logo
  • storage case
  • warranty card
  • conterfeit protection card
  • short user guide

The most irregular here are 2 cables provided from the factory. We don’t remember reviewing any other IEMs that would give you same options straight out of the box. Of course, this makes Oxygen more universal in terms of usage scenarios but we’d still vote for other cable options or adaptors for different output standards — 2.5mm balanced/3.5mm unbalanced/4.4mm balanced. This would give more freedom to any audio fan and justify higher price tag.


Storage case is another great accessory to have out of the box. It is neat, good looking and has the brand logo empossed at the top.


Oxygen shells are made of two perfectly aligned stainless steel parts: top cover and base. The joint is imperceptible to finger touch and almost invisible. Top cover has the additional grinding across the surface with polished model name (right channel) and brand logo (left channel). Reflections caught by those elements create stunning look of a luxury item.


There are two compensation openings for dynamic driver — one is located on the inner part of the base, close to output nozzle and another one is at the bottom edge.


R|L channel indicators and brand|model name are also located on the inner part of both bases. Those imprint are done by grinding which is much better than using paint which would eventually fade away.


Output nozzles protruding from bases and have special retaining notches for exchangeable eartips.


2pin, 0.78mm connectors don’t show any free play or rattling and have very tight fit for the incoming male pins.


In overall, the design is minimalistic and clean. The quality of crafting and build is nothing more to be desired — everything is as perfect as it should be in IEMs of this price segment. The combination of polished and grinded stainless steel surfaces dedicate much to the attractive look.


Both cables come with straight 3.5mm gold plated audio jack in aluminum housing, springy earguides, aluminum Y-splitters|limiters with brand name imprints, plastic housings of 2pin connectors and channel marks located there as well (red for right and blue for left). Audio cable for smartphones is also equipped with inline remote (volume +|- buttons) and mic. Packed in black silicone braid.


Other cable for pure audio sources is thicker, has the extra quality feel and packed in transparent silicone braid.


Fit comfort:

As first, you might think that Oxygen should be heavy IEMs due to stainless steel shells. In fact, this choice of material is compensated by smaller size, thinner profile, very natural shape and good earguides. Shape and profile are similar to DARKSIDE model that has the excellent fit. Same here — Oxygen IEMs are easy to get used to and become almost insensible while put on. Another good outcome of this is more than the average noise isolation. No driver flex spotted either.



Tested with Hidizs AP80, xDuoo X3 DAPs

Lows and midbass:

Perhaps, the best sound characteristics of Tanchjim Oxygen IEMs is the ability to accurately resolve and gently deliver the lower range. If DARKSIDE were kind of bass-heavy IEMs that built their nature upon this range, Oxygen is very delicate in this respect. Bass extension is still very good but more important is that its texturing and clarity is at much higher level. Bass can reach the lowest registers, maintains great clarity and not interferening or mixing with mids and treble. This range is not accented at all but always present and stays obvious to enrich the sound and widen the stage. Speed of decay is reasonably fast, contours are clearly defined. Great implementation and tuning for those who search for balanced lower range delivery.

Midbass section is at the same high level — fast, powerful and tight. No shortage of air or articulation to reproduce drum sections naturally. In contrary to hybrid types of IEMs, the influence of treble is not as prominent resulting in more weight added to lower reverbs rather than higher ringing. This also defines Oxygen IEMs as tending towards darker tonality.


Mids and vocals:

The most of the resolution and accent is located at the mid section. Vocals are sounding rich, thick and take the leading role in the entire picture. No significant skeweness noticed between female and male voice gains. Both sound natural, lively and exposed, both have a touch of warmth. Of course, female vocals are bit more influenced by the lower treble but since it is coming from the dynamic driver — no excessive brightness or harsh sounds are present. Good resolution is observed on vocals and instruments of this range. Despite that some instruments are bit laid back in comparison to vocals — there are still plenty of details that actually reminds of some armature rivals with delicate tuning of mids. Sound of electric guitars as well as other instruments is full bodied with lots of natural harmonics. Another good characteristic is the impressive instrument separation that also adds much to the significant stage depth.



Treble is perceived as clear and balanced to mids, sounding a bit more pronounced than lows. Extension, resolution and micro dynamics are outstanding for single dynamic driver IEMs but not as sparkling and vivid in comparison to armature models. The most presence and detalization is gathered in lower treble which adds the feel of transparency to the sound. This range is perfectly controlled, accurate and totally enough to balance bass or accented mids without puting much stress on your ears and allowing to have have long listening sessions. Of course, no piercing sounds, no extra sharpness produced by treble and no problems with hisses or sibilances as a result.



As already mentioned — very capable IEMs concerning the the size of imaginary stage. Not afraid to say that Oxygen are leading now in this respect among all other dynamic models that ever got to our hands. Good instrument separation with significant spread in their position together with quite a wide space produced by lows and treble, plus the voices that are brought to front — all create a good feel of wide and deep stage.


Sound in overall:

Tanchjim Oxygen sound can be described as moderately dark and balanced, with slight accent on mids and vocals, great texturing of lows, good overall resolution, clear and natural voices and slightly warm timbre. Surprisingly good for any genre, including heavy metal and rap. Not the best choice for bass heads due to accurate and weighted delivery of this range instead of simply overemphasizing it.

Compared to Earnine EN2J:


The only IEMs that we’ve examined so far with the similar price tag — Earnine EN2J from South Korea. Many similarities between the two: shells made of stainless steel, small size, great fit. The main deifference is that Earnine EN2J belong to pure armature type of IEMs with better extenson of treble, more resolution in overall and better micro-dynamics. On the other hand — lacks in bass and midbass reproduction in comparison to Oxygen. EN2J does also sound quite warm, thanks to treble driver tuning, but still cannot compete in the extension of lows and richness of midbass range. Therefore, good opportunity to get the right model choosing from those two — either the more resolving and appealing lower end of Oxygen or better extension and higher clarity of treble of EN2J. But both sound pretty balanced when are not directly compared to each other.



Two main definitions followed us while we were examining Tanchjim Oxigen IEMs and writing this review: accurate and clean. This addresses both — overall design and sound. There is nothing much to talk about or to admire in Oxygen appearance but at the same time such minimalistic approach, perfect crafting, clean look and natural profile represent the maturity of this model instead of incorporating screaming design to hide some drawbacks behind its exteriors. Sound quality and tuning spreads this idea further — accurate and weighted delivery of all frequency ranges resulting in balanced sound with slightly warmer tonality and wide soundstage. This is much better than having severe accents on either range to identify that IEMs are capable of only few genres. All in all, Tanchjim Oxygen do create a feel of fundamental and mature model regarding every single aspect and really impress with most of its sound characteristics. It would be hard to find any other match if the dynamic driver model is preferred.

You can purchase Tanchjim Oxygen at PenonAudio store

Video ad from Japan:

I got very interested in this Tanchjim, also on the Hidizs MS4, after saw your Kanas Pro review. How do you compare The Oxygen and the Hidizs MS4 in terms of sound quality? By hearing, do you think that the Oxygen or the MS4 follows the Harman Target Curve, just like the Kanas Pro? Thanks in Advance.
I prefer the fit and SQ of the Oxygen over that of my KPE. It just has a more likelike presentation with superb imaging and depth. I have not heard the MS4 but I have found very few IEM's over the many years that I have been involved with this hobby that have impressed me as much as the O2.
@HiFlight would you compare it favourably to Moondrop Kanas Pro and Periodic Be?