Effect Audio needs no introduction for audiophiles that are into headphone audio. They are well-known for their high-quality aftermarket IEM cables, being one of the first brands to commercialize it for good to a wider audience.

It might come as a surprise though, that they’ve just come up with their second IEM release to date – the hybrid Axiom. Their first IEM, King Arthur ($6999) has been a polarizing product ever since its release back in 2019. It shouldn’t come as a surprise though, as releasing a first IEM and pricing it at $6999 was a risky move, to begin with. Two years have passed and now Effect Audio brings a new product to the market, and it’s a really interesting one, having some aspects that have never been seen before. 


The unboxing experience of the Axiom is really interesting and polished, hence we decided to cover it in a standalone article that has been released a couple of weeks ago. Nonetheless, this wouldn’t have been an Ear Fidelity review if we’d decided to skip this part, so here’s what has been already covered in the unboxing article.

Looking at the box we can clearly feel the Apple vibe – it’s small, even for an IEM. However, looking at the fact that there’s no cable included in the packaging, and the set of accessories is rather small, it should come as not a surprise. 

Still, the box is really pretty with an interesting color scheme. The branding looks well-thought and polished. I’m not gonna lie – I really, really like it. The graphics and branding look mysterious and really like nothing else. 

Inside of the actual outer box is… another box. It’s always good to have additional protection and more space to put those cool graphics on. That’s not all though. From the very first time I opened them up I was sure I can feel a rather unexpected smell, so I started to dig into the packaging, and I have found…tea. I’m not planning on making an actual tea out of it, but the scent is really interesting. If Effect Audio is going to ship it to normal customers, then I actually think it’s a wonderful idea. Pushing the limits when it comes to the presentation of the product, aren’t they? Nice touch!

Design, Build and Comfort

Now, let’s get into the IEMs themselves. From the first moment I saw them on press materials I felt like it’s a beautiful IEM, but now that I have them in my hands…this feeling is even stronger. 

The whole construction is made of aluminum and titanium alloys. It feels very substantial in the hand, and the level of craftsmanship is high. The actual faceplates are made of Hetian jade and they look absolutely spectacular, just take a look at the photo above. The nozzle is made of a titanium alloy and should be very resistant to everyday use.

Even though the Axiom is on the heavier side, it fits me just about perfectly. The shells are rather chunky and big, but the overall shape is well designed and simply put – comfortable.
Effect Audio has been using the word “Sustainability” in promoting their new Axiom IEM, and here are a few words about it:

“This is probably the first personal audio product in the world to be designed with sustainable features from the moment of its conception. In addition to minimized packaging and included accessories, this is also the first in-ear monitors in the world to include a Modular Unit (MU) System that promises maximum scalability and user interactivity for years to come.”

It’s good that more and more companies start to really care about this whole sustainability theme. There’s one thing though – Effect Audio, THE brand that brought us high-end aftermarket cables…doesn’t include any cable in their latest IEM.  I get the idea why, I somehow understand that approach, but I’ve heard more than a dozen people complaining about it already, and having in mind that it’s a fresh product says a lot. It’s a rather controversial decision and I see why so many people are complaining about it – this is a $1499 pair of IEMs, include even your basic model to give people a good start.


At the beginning of this review, I stated that the new Axiom is an IEM utilizing features that have been never seen before in the market. The most important one is their Modular Unit (MU) System, which lets you swap between MMCX and 2-pin connectors, giving you brilliant flexibility when it comes to cable pairing. 

To swap the unit, all you have to do is undo a single screw and choose if you’re going for MMCX or 2-pin, with more variants coming up in the future. This is a great idea that’ll hopefully get used more often. I myself have many aftermarket cables that I can’t use with some IEMs because of a different connector, and this little thing is a lifesaver in this kind of situation. 

Effect Audio has been really good in this kind of idea lately, first, they introduced their conX system, which basically made any IEM cable compatible with almost every single IEM on the market. Now, they bring it to the other side of the equation, and because of that, we all have to crown Effect Audio as the connector king of portable audio.

Apart from the MU system, there’s nothing to write a book about. The Axiom uses a hybrid design, with a single 12mm magnesium dynamic driver with LCP suspension for the bass and midrange, as well as a twinned FK-series Knowles Balanced armatures for high frequencies. It’s nothing impressive, but as we all know by now…it’s not the driver count that matters. 

Lastly, the Axiom rates at 32Ω impedance and 112 dB sensitivity, which makes it rather easy to drive. 


Effect Audio describes the Axiom as “non-fatiguing” and “reference”, and I don’t think I could agree with those statements. For me, the Axiom is most definitely a V-shaped, high contrast IEM, with a focus on the bass response.

Let’s start with that bass. It is definitely big, hard-hitting, very physical, and very impressive. You can definitely hear that 12mm big driver, as its overall presentation is definitely quite boosted. Don’t get me wrong though, I actually really, really like it. There’s just something extremely pleasant about that thick, roaring bass presentation which at the same time is well-controlled and exceptionally precise. Ever since getting the Axiom, it is my go-to IEM for electronic music, since it offers that high-contrast and very dynamic sound that suits that music genre perfectly. 
Speaking about electronic music, let’s take a song called “Alive” by RÜFÜS DU SOL. It is a very dynamic and big-sounding track, that has some great bass passages here and there. I find this song quite unappealing on many IEMs and headphones that struggle with that powerful and somewhat in-your-face type of music, but the Axiom handles it exceptionally.
The bass delivery is boosted, clean and physical, giving you a great amount of fun while listening to this track. 

The midrange is slightly recessed and it mainly focuses on resolution and immense detail retrieval. Female vocals might sometimes sound a little harsh, but it mainly depends on the quality of the recording. It is because of the tuning which is actually a V-shape with the boosted bass response and the transition between the higher midrange and lower treble being significantly forward sounding. With good masterings, this kind of tuning sounds marvelous, and the Axiom offers a spectacular detail retrieval, but it’s not too forgiving when it comes to the source material.
A great example is an album called “Unplugged” by the British Trip-hop legends Archive. It is an unplugged live album that is packed full of little details, such as fingers sliding around the guitar neck, vocalists inhaling etc. The Axiom handles this album spectacularly, creating a very detailed and spacious sounding experience. 

The treble is yet again full of energy and forward sounding. It once again proves the Axiom to be a great choice for electronic music and rock, being an intense and fun type of listening experience. While there’s a certain peak at around 6k, giving the Axiom a quite edgy and harsh sound from time to time, the overall presentation of the high frequencies is entertaining to listen to. 
If you’ll choose a well-mastered album, such as Nils Lofgren “Acoustic Live”, you’ll be left with a highly detailed and impressive sound performance. Every little sound of an audience, Nils sliding his fingers around the neck of his guitar, this is the IEM that could show you details that you’ve never heard before. Be careful though, as with badly mastered albums the Axiom could sound a bit too intense in the upper regions of the frequency response. 

The soundstage is one of the best aspects of the Axiom. The size of the stage is quite impressive, both in terms of its width and depth. The layering and imaging, while not the best in the price range, are both great and they do give a great feeling of immersion. 
While I won’t call the soundstage of Axiom as impressive as that of Unique Melody MEST, it is a good opponent for Fir Audio VxV, Campfire Audio Solaris 2020, and Final A8000. I’d call the overall soundstage capabilities as natural and precise, not being intimate, nor too vast and spacious. It is a good type of staging that complements the overall fun sound signature of the Axiom well.

MU Modules

Surely, the elephant in the room is the revolutionary idea from Effect Audio called MU Modules. Let’s dig into it a little bit more, as it has a feature that I wasn’t aware of, and it can be a surprise for you as well.

See, the MU Modules are NOT just different types of connectors. When I first saw the Axiom I thought that these are to change the termination between 2-pin, MMCX, and some others and that it’ll be basically the only purpose of this new technology. How surprised I was when I found out that Effect Audio is sending me the new modules that are meant to alter the sound of the Axiom. 

The first additional module to be released is the YU module. It’s really easy to differentiate it from the OG one, as this time it is silver, instead of black. 

When it comes to the sound difference, I was actually quite surprised with how little of the change it was. The YU module has a more organic, warmer tonality with a slightly more forgiving and rolled-off treble response. While both modules offer very similar bass and midrange response, the biggest difference is in the treble performance. While I won’t call it a day and night difference, it is great to see that you can finely tune the Axiom to your liking. 

Personally, I stick to the OG module as its more forward and high-contrast sound is more appealing to me. The comparisons have all been done with the OG modules installed, so take note. Changing the modules to YU won’t really change the outcome too much, but it is definitely worth noting. While the Axiom with YU modules is slightly more relaxed and less extreme sounding, it is still a fun provider without a doubt. The difference is there, but it’s rather subtle. 



Unique Melody MEXT

Right from the beginning, it’s easy to notice that both of these IEMs are fun providers.  It is how they achieve it that makes them quite different though.

Overall, the MEXT is slightly thinner sounding, but it actually makes them sound more precise and it boosts the separation. The bass is more hard-hitting and more physical in MEXT, due to its revolutionary OBC driver. The Axiom however sounds more “normal” and is also great in terms of impact and kick. The midrange is warmer and smoother in MEXT, while the Axiom focuses more on the upper-mid region. The treble has a similar extension, but the MEXT is more relaxed and smooth sounding. 

When it comes to the soundstage, the MEXT produces a bigger and more precise image. The Axiom is slightly more intimate, but it also does great job with imaging. Having in mind that the Unique Melody MEST is the best staging IEM that I’ve ever listened to, the MEXT is not an easy opponent for the Axiom to say the least. While it’s not as good, it’s still a good staging IEM. 

Cayin Fantasy

This comparison is really interesting, as both Effect Audio and Cayin are NOT doing IEMs on a regular basis. For both of the companies this is a second attempt into the IEM world, so let’s see who did it better. 

Overall, these two IEMs are very different, especially in the tuning department. Starting from the bass, the Axiom is much larger, more physical, impactful. The Fantasy is a bass-light IEM and its low frequencies are a no match for the Axiom, which is much better suited for the majority of music genres and use case scenarios. The midrange is much leaner and sharper on the Fantasy, making the Axiom seem really thick and bold. While the Axiom does a great job with most vocals, the Fantasy shines with female voices, but it lacks body for male vocalists to sound natural. The treble is slightly boosted in Axiom, but the Fantasy is an overly-bright IEM and it comes up as more pronounced, sharper, and less forgiving to say the least. 

Overall, the Axiom is a much better tuned IEM that will definitely suit much more people than the more specialized Fantasy. While the build quality of the Axiom is great, I find the overall design and finish of the Fantasy even more spectacular. Having all the aspects in mind though, I find the Axiom to be a safer and simply better introduction of the brand to the vast IEM market.

Campfire Audio Solaris 2020

Here is a completely different story. Campfire Audio has been known for making IEMs for years now, being one of the top dogs for years, ever since releasing their highly popular Andromeda.

Their current flagship, the Solaris 2020 has a similar goal to the Axiom, but once again, the approach is different. The Solaris 2020 is the more romantic, richer, and more forgiving sounding of the two. Its biggest strength is its beautiful, lush midrange performance and an overall sweet timbre. The Axiom on the other hand is more dynamic and it’s harder hitting in the bass region. When technical capabilities are concerned, I’d say they play in the same league, providing good detail and resolution, while not being the best in class.

This will come to a subjective approach – if you crave that more romantic, smooth and liquid-like midrange, the Solaris 2020 is going to be a better choice for you. However, if you’re looking for a more fun-oriented, extreme-sounding IEM that will handle metal and most electronic music, the Axiom is your guy. Actually, you could go for both, as the Axiom would be a great choice for your everyday outside activities, while the Solaris 2020 will make your evenings chill and warm. 

Final A8000

Let me start by pointing out the fact, that the A8000 is $500 more expensive, coming at $1999, compared to $1499 you’d have to spend for the Axiom. 

The build quality is pretty simple – the A8000 is still the IEM to beat in basically any budget. It does have slightly sharp edges and it’s both scratch-prone and massive fingerprint magnet, but it just looks spectacular and very industrial. 

When it comes to sound, the A800 is faster, more precise, and due to its famous hyperfast sound, it comes out as more technically capable. On the other hand, the Axiom has a thicker, more rumbly bass response and a more forgiving nature. While both are excellent at providing fun, the Axiom is more universal due to its less clinical tuning. 


Effect Audio has been a legendary aftermarket cables manufacturer for many years, and now they enter the IEM market with confidence. The Axiom is a revolutionary modular IEM that is tuned for a fun and engaging experience. With its high flexibility and gorgeous design, combined with a sound signature to enjoy, it surely is a great offering for their truly first IEM. While its price is a little high, the potential of this product will only grow when more and more modules get introduced. For now, the Axiom gets our recommendation, but when (or if) Effect Audio will eventually come up with TWS modules it’ll be a very exciting day for all IEM enthusiasts. The sky is the limit.


Gear used during this review for the sake of comparison and as an accompanying equipment:

IEMs – Unique Melody MEXT, Unique Melody MEST, Final A8000, Cayin Fantasy, Campfire Audio Solaris 2020, Fir Audio M5Sources– EarMen Tradutto, Topping D90se, XI Audio Broadway S, Ferrum OOR, Cayin N3Pro, Cayin N8ii, Fiio M11 Plus ESS, Fiio M17

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