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CustomArt Ei.3


Looking to spend around $300 on earphones? Would you like to try customs? Read on…

CustomArt started out as a manufacturer of silicone custom IEMs and rapidly made a name for themselves with beautifully tuned and crafted IEMs. Piotr, the founder of CustomArt was a fan of IEMs before he became a maker of IEMs so you know that anything he makes will be built for both enjoyment and performance.


CustomArt Ei.3 left & rightThe Ei.3 is CustomArt’s first venture into acrylic IEMs and is priced at an insane sub-$300!! At that price it competes directly with brilliant universals like the AudioFly AF140, various DUNU and FIDUE earphones, and plenty of other contenders, but none of those competitors offer a custom fit which, if done right, will always out-fit and out-perform an equivalent universal.


I haven’t been able to find a definitive listing of the Ei.3’s specs (probably because it’s a brand new product), but here’s what I do know:

  • Drivers:  3 x balanced armatures
  • Impedance:  65 ohms
  • Cable:  detachable, ~4 feet long
  • Sockets:  industry standard 2-pin, surface mount

Beyond the specs, I can tell you that the intention for the Ei.3 is to be a fun-sounding IEM for lovers of electronic (not my favourite genre) and bass (OK, you’ve got me a bit more interested now). In Piotr’s own words from one of the original ads, “the Ei.3 is intended to sound big and bold”.

After biting the bullet and selling my beloved Shure SE846, I really hoped that the Ei.3 would fill the gap when I wanted a thumping, bass-first experience (which I occasionally do), but the reason I actually own these is important for me to share. I was contacted by Kamil from CustomArt to discuss the purchase of some IEMs at a discount in return for a review (a win-win scenario). Unfortunately I’ve been completely strapped for cash lately so I couldn’t scrape together the funds for one of CustomArt’s flagship CIEMs. As luck would have it, they soon released news of this budget beast and were kind enough to offer a pair to me at no charge in order to help get the word out so I had fresh impressions made and shipped them off to Kamil and Piotr with much gratitude and a little excitement (I say ‘a little excitement’ because I really had no idea what to expect).

Boy am I glad that CustomArt offered this opportunity to me and I think you will be too once you read this review. Piotr and his team have set a new benchmark in price:performance ratios with the Ei.3. As you may know from my previous reviews, freebies don’t equate to an automatic good impression and I’ll happily say so if I think a product misses its mark, but the Ei.3s are not an example of this in any way – they not only hit their mark, but surpass it with ease in almost every way.

Packaging & Accessories

The Ei.3s come shipped in a Pelican 1010 case with a moisture absorber, cleaning tool, and the CustomArt cable. There are no frills or embellishments, but there’s nothing left wanting (except perhaps a microfiber cloth). For a $300 CIEM it’s a pretty good deal when you’re getting both an excellent set of earphones and a high quality carry case too.

Fit & Finish

During the design process, I told Kamil that I had always wanted clear CIEMs, but that I was also happy to receive whatever design Piotr chose (in case he wanted to show of his creativity and design expertise). What I received was a perfect compromise of a simple, but attractive flourish from Piotr and the clear shells I’ve always liked the look of, but never owned.

The shells and tips of my set are clear acrylic with faceplates that are translucent with a diamond pattern in them (red on the right, blue on the left).

With the clear shells you can see that there are some imperfections in the shell where the inner surfaces are a little hazy and there are a few bubbles and patches to be seen on close inspection so the Ei.3 won’t compare in build quality to best-in-the-business acrylic manufacturers like Noble, but this is a purely aesthetic issue which may not matter to some people and certainly doesn’t worry me greatly. When you’re not inspecting them closely (which is 99% off the time), the Ei.3 look great and there are plenty of design options to choose from on CustomArt’s website. Also, keep in mind that opaque colours will completely negate the issues caused by transparent colours where you can see internal blemishes.

Edit: Since writing this review, Piotr has informed me that this pair of Ei.3s were about the 4th or 5th set of acrylics they ever made and they have put a lot of work into further improving the quality of the finish since these. No doubt future reviews will reflect these improvements and given that these are already quite OK, the future quality is likely to be at least on par with all manufacturers.


What’s more important than the up-close aesthetics is the way a custom fits your ears based on the correct use of the ear impressions provided. I have to admit that I was curious to see how well the Ei.3s performed in this regard given that they’re CustomArt’s first ever acrylic product. I don’t know if the design process is significantly different from the silicone they made their name with, but I have to admit that I had my doubts.

Well I’m almost embarrassed to think that I ever doubted the fit of the Ei.3s because they’re perfect. They are absolutely as good as my Noble K10s in terms of fit and comfort and that’s high praise. Even my UM Miracles never fitted as well as these Ei.3s so Piotr clearly knows what he’s doing when it comes to trimming and adjusting the ear moulds to create acrylic customs.

Size, Shape & Design

Being a 3-driver custom using balanced armatures, the Ei.3 are as small as they probably can be (after all they have to fill your ear in order to stay in place). They fill the main bowl (concha) of the ear nicely, but have a flat profile that means they don’t stick out of the ear so they’re a lot sleeker than some of the million-driver behemoths being created now.

Looking inside the Ei.3 you can see 3 distinct BA drivers. The mid and treble drivers are nested together firing into a common sound tube while the large bass driver sits on an angle to make it flatter and is a bit further from the ear canal firing into its own very narrow sound tube. The choice of tube length and diameter is part of the voodoo of frequency management and time alignment in IEM design that I won’t even pretend to understand, but suffice to say, whatever Piotr has done here works to perfection. I can’t tell if there is crossover circuitry built in or if the crossover points are a function of each individual driver’s range of capability, but none of that really matters if the earphone sounds good, right?


The Ei.3 is meant to sound big, bold and perfect for bass lovers, and it comes from a company that I’ve always thought of as slightly treble and resolution-oriented so I expected a very v-shaped sound with thunderous and perhaps slightly boomy bass accompanied by some bright and energetic treble… boy was I wrong!

Piotr has tuned the Ei.3 to near perfection and given that he’s working to a budget (remember these cost <$300) and using just 3 BA drivers he has crafted something close to a miracle.


The treble from the Ei.3 is clean and detailed with a slight forwardness that lends the CIEMs some immediacy and energy without ever becoming harsh or fatiguing. The Ei.3s never leave me wanting more from the treble, but also never bite. If this is the CustomArt house treble tuning then consider me a fan.

Strummed guitar strings have a nice edge to them and cymbals have the ability to pierce (in a good way) and shimmer. I wouldn’t describe the treble from the Ei.3s as being breathy or airy, but they’re perfectly balanced just below that level. In other words, breathy vocals and brushes on snare drums have texture, but it’s not enhanced or over-present. There is a subtle sense of roll-off from the Ei.3 when compared to slightly more extended IEMs, but it’s only noticeable in comparison and they don’t sound particularly rolled-off in isolation.


I love vocals and mid-range instruments so I would have been quite upset if the Ei.3 were too v-shaped with a canyon in the mid-range, but if anything they have a very slight lift in the mids that helps to pull everything into perfect focus.

Both male and female vocals are rendered with clarity and speed, but still with suitable weight. The mids from the Ei.3 are not lush or creamy so I wouldn’t recommend these for people who like the heavily mid-centric sound of SE535s or SE846s, but you’re not sacrificing vocals if you choose the Ei.3s – you can have your cake and eat it too.

There’s not a lot more I can say about the mids. They’re just right and perfectly balanced with the rest of the auditory picture cast by the Ei.3. They’re not the star of the show, but they’re also not left out the back somewhere to be forgotten.


OK, here’s the moment you’ve been waiting for… do the Ei.3s live up to their intention to be big and bold?

Well, not exactly, but that’s not a bad thing. You see, I’m measuring ‘big and bold’ against some of the best in the business – namely the SE846. Even so, solely on their own merits I would describe the Ei.3s as dynamic and engaging rather than big and bold.

The bass from the Ei.3 is punchy and agile, but it doesn’t go super deep. Music has an engaging pace and pulse from the Ei.3, but I personally don’t think of them as a bass-first IEM so much as a well-balanced IEM tuned for full-frequency enjoyment which, in my opinion, is better because it’s more versatile across wide-ranging genres.

The bass from the Ei.3 is punchy enough to translate the percussive wave from kick drums and has sufficient rumble to give a bass (guitar or upright) its correct body and reverb. Electronic, sustained bass is appropriately solid and textured to provide the foundation for the sonic landscapes laid over the top. In short, the bass is very, very good – it’s just not the star of the show and that’s completely fine. Don’t expect the Ei.3s to satisfy your bass cravings if you’re a loud-and-proud bass-head. These are bassier than neutral, but not bass-oriented.

Staging & Imaging

The Ei.3s have a really engaging presentation that’s sharply focussed, of good size, and coherent and natural.

What I like most about the presentation from the Ei.3s is the clear placement of each sound. The stage isn’t huge and expansive, but the sense of space is just right so that everything is perfectly placed and feels well-spaced and never congested. There’s also a nice perception of height created if you listen for it, but it’s all subtle enough to not distract from the music so much as enhance the overall experience.

As much as I love a big soundstage, I prefer overall coherency and realism which is where CIEMs like the Ei.3 and Noble K10 both excel so I’m finding myself drawn more to those types of presentations on late.

Speaking of the Ei.3. and K10 in the same sentence…

CustomArt Ei.3 vs Noble Kaiser 10

It’s unfair comparison time!

Let’s set the scene here before going to far. The Ei.3 costs <$300 and uses 3 drivers per side while the K10 costs $1600 and uses 10 drivers per side. This really shouldn’t be a comparison, but there’s a reason I’m choosing to continue on this fool’s errand…

When I listened to the Ei.3s after spending much time with the K10s, what struck me most is how similar the Ei.3’s signature is to the K10s. Don’t get me wrong, the Ei.3s are not at the same level as the K10s, but they share similar tuning despite coming from different companies.

What both IEMs do very well is balance the bass, mids and treble equally without any frequencies competing or getting lost. Where they differ is that the K10 offers deeper, more authoritative bass, a richer mid-range, and better treble extension, but the differences are in the quality and authority rather than drastically different sounds.

As you’d expect, the K10s are clearly superior in the subtleties of layering and textures and the overall sound is slightly more coherent, but the Ei.3s are also excellent in that regard so there’s no slight on the Ei.3s here. Stage-wise, the Ei.3s sound slightly larger than the K10s (particularly in terms of stage width) most likely due to the slightly fuller bass from the K10s.

So, there’s no doubt that the K10s are superior in every way, but the Ei.3’s tuning is an incredible feat from a sub $300 3-driver IEM.


CustomArt have succeeded in creating a massive, potentially industry-shaking statement IEM with the Ei.3. Normally statement pieces are TOTL offerings that many can only hope to one day afford, but the Ei.3 are an outstanding performer that almost all enthusiasts can afford. They are an amazing entry point for anyone contemplating the plunge into custom IEMs and are an equally good option for those already enjoying customs but looking for an additional CIEM with different tuning.

The Ei.3 is a well balanced-IEM that leans towards warmth, bass and engagement. It won’t compete with the best treble / detail IEMs, mid-range centric IEMs, or bass monster IEMs, but it will give you an excellently balanced sound that is completely enjoyable with any genre. In other words, the Ei.3 isn’t about technical superiority in any one area. No, where the Ei.3 excels is its versatility and ability to engage the listener in every track and to make your music fun and lively without colouring it or distorting it in any way. I used the Ei.3s on two 3 hour flights recently and didn’t once long for my K10s because the Ei.3s do everything extremely well. The Ei.3s won’t be replacing my K10s, but they will certainly get regular use because they’re such a great-sounding earphone. For the price I don’t believe you will find a better earphone unless you’re looking for a very specific sound signature.