
Disclaimer
My name is Jérémie, I’m a 36 years old audiophile from Paris. I think I’ve always had audiophilitis, but things only started to get bad last year when my SM3v2 died in February 14. Looked for a replacement, and 18 months later I now have 4 customs (H8Pro, SE5, Ei.XX and Ei.3), one universal (SA7, having sold my SM64), have been through a handfull of DAPs, and just got started with headphones (HD800 plus Lyr2/Gungnir Multibit combo).
In the end, I just love music. That’s all it’s about. I love to feel the details, the attention that the creator thought of and put into his creation. I’m also a sucker for violins and drums, which are my favorite instrument.
I was invited by Piotr to be part of a team of 4 Ei.XX reviewers. Of course I was thrilled and accepted to join. My Ei.XX were provided free of charge for testing purposes, and I have no financial interest with Custom Art or Massdrop or other sort of joint interest that may skew that review.
For due note, I have written a preview of Ei.XX (
http://www.head-fi.org/t/778219/teaser-massdrop-x-new-custom-in-ear-monitor-available-september/315#post_11933896), as well as a review of Custom Art’s Ei.3 (
http://www.head-fi.org/products/customart-ei-3-acrylic-custom-iem/reviews/13821), and Harmony 8 Pro (in French,
http://www.tellementnomade.org/test-des-harmony-8-pro-custom-art).
Introduction
Methodology
This review is based on a total of 120 hours of Ei.XX sessions. Half was made with my iPhone 6 in pure nomadic mode (Parisian subway, street, bus, etc.), and half was made on my desk rig (Schiit Gungnir Multibit and Lyr 2 with Reflektor SWGP ’74 tubes).
I tested the following cables: Linum BaX, Linum Music and Thor Effect Audio. In general, they did not influence sound experience, and when they did, it was extremely limited (in fact, only the Linum BaX appeared to have an effect, by slightly tightening the bass and pushing the trebles, but we’re really talking small minor details here). In actual use, I now go with the Linum Music with the iPhone 6 because you just don’t feel it on the go, and the Linum BaX at my desk.
From September 20 to October 20, I listened exclusively to the Ei.XX, having listened exclusively to the SE846 in September. On October 24, I performed a comparison of the Ei.XX and the SE846 which you can find at the end of this review. I also listened just a tad to my Harmony 8 Pro sometime in between.
Please note that I am NOT a basshead (some people even call me a treble head, but I think they are wrong), I am NOT the typical Ei.XX target, since I mainly listen to rock (around 85%), and only 10% of my listening is EDM, Rap or Hip Hop (for the curious lads, the 5% remaining are classical and soul. DUH). I also listen at levels which are usually considered as very moderate to very low. This point I cannot stress enough. Listening at different sound levels will likely lead to different experiences, but, as you’ll see, I did turn up the knob.

Presentation
Ei.XX are the result of the collaboration between Custom Art and Massdrop. This ciem features 6-drivers (2 super low, 2 low, 1 tweeter, and 1 super tweeter), 4 ways and 2 soundtubes. Those who know Ei.3 will be interested to know that the small soundtube is gone, and has been replaced by a much larger one.
Of course, collaboration with Massdrop means…Massdrop.
Ei.XX are thus not bound to be part of the Custom Art lineup (as far as I know), and they ought to remain for sale only through Massdrop. The first drop started on September 28 and was a resounding success, with Ei.XX finding 50 new homes in less than 73 hours. There is no doubt in my mind that further drops will happen, including in a not so far future.
Of course, before we go any further, the price is $600 (plus shipping and extra with you want crazy personalization – and trust me, Piotr is up for it, he’ll take on almost ANY challenge).

The packaging / The Fit
Packaging is standard Custom Art, that is, the Pelican 1010 box with a cleaning tool, Ei.XX with cable and a neat warranty / introduction card.
When I received my Ei.3, the fit was good and comfy, yet not as tight as with my Harmony 8 Pro or SE5. The situation is different with Ei.XX: the fit is perfect, and if it wasn’t for the nature of acrylic (which imho isolates less than silicone), the isolation would be identical to that of Harmony 8 Pro and SE5. Please note that those were made after impressions that I sent Piotr from over a year ago, which means that well-made prints can yield long lasting results with the right artisan
SE846
I’m introducing this here because when I joined in, Piotr asked me if I could try and make some Ei.3 and SE846 comparisons. I thus borrowed SE846 from a friend (blue filters, Shure olives), and listened exclusively to them for two and a half weeks preceding the reception of Ei.XX. I used exclusively the tracks mentioned in the Ei.3 review.
As a result, quite a bit of the following will be made in reference to SE846 and Ei.3.

The sound
Scene and separation
The Ei.XX soundstage is quite pretty. It is clearly out-of-head, and always showcases a great precision, mainly due to their trebles imho. While it is not the widest soundstage I have experienced in any dimension (width, depth and height), it is very homogeneous, albeit appearing to be slightly wider than deep. Yet, it remains markedly smaller than say, the soundstage of Harmony 8 Pro.
To give a proper example, if you listen to ‘
Myopie’ by PandaDub, the tuba/trombone (can’t quite tell if it’s one or the other) at about 1’36 comes at you from faaaar away, deeeeeep. The same goes with the resounding effect at about 0’43 in ‘
Feral’ by Radiohead. Not only does it come from far away, but its position is clearly defined, to your right in your back and slightly over your head (I’ll spare you the metric measurements).
As a result, the Ei.XX and Ei.3 soundstage are hardly comparable, because the Ei.XX soundstage showcases a real depth. I also have the feeling that the Ei.XX is a little less frontal (or less close) than that of Ei.3, but this could relate to the Ei.3 having very little soundstage depth.
Compared to SE846, the Ei.XX soundstage appears less wide. In this case it is a quality for me: sometimes, the SE846 give me the impression that they stretch the soundstage laterally, to the point that the center, right in front of me, feels kind of empty. Also, the SE846 appear to lack soundstage depth quite sorely when compared with Ei.XX. But they seem to be even in terms of soundstage precision.
The amount of details appears similar at first, but an attentive listener will find that the Ei.XX actually reproduce micro-details with much more brio than the SE846 (you’ll see more on that in the comparison I made on some tracks at the end of this review). However, be it with the Ei.3, Ei.XX or SE846, ‘
On every street’ and ‘
Telegraph Road’ by Dire Straits are impeccably reproduced. The difference really lies in how immediate and acoustically readable the details come out, like the cowbell at about 3’50 on ‘
On every street’, which is much more clearly rendered by the Ei.XX than the SE846 for instance.
The separation provided by the Ei.XX appears to me like it is just a tad below that of the SE846. But given the fact that Ei.XX shares some family traits with Ei.3, I expected no less from them, with Ei.3 being already a solid performer (if you take into account their weakness in the trebles). After many comparisons and repetitions, I think it relates to the more airy nature of the SE846 trebles, and to the warmth and coloration of the Ei.XX.

Bass and sub-bass
The Ei.3 were a big step up in terms of subs quantity in the Custom Art family. The Ei.XX go further and even outdo the SE846.
At first, I found that the bass of both iems were comparable, and would probably not be all that easy to distinguish. And then I realized that I wasn’t volume-matching when I was switching from one to the other (precisely because the bass and overall volume level appeared pretty close).
But the fact is that the SE846 are more sensitive than the Ei.XX, which are already a pretty sensitive bunch. Long story short, the Ei.XX can make my Lyr 2 and its 0.3 Ohm impedance output whisper, but the SE846 will make it hum distinctively.
So I started over my sessions, but this time I took care to volume-match when going from one to the other. To give you an idea, I used two soundwheel clicks on my Headstage Arrow 5TX. And that made me change my point of view.
Concerning the Ei.XX, you’re looking a textured and full bass and sub-bass. I would tend to think that the bass texture is akin to that of Harmony 8 Pro, except that there is quite a bit more of it. And for sub-bass, well there is a lot more of it.
During my first day with them, it felt too much despite my listening to the SE846 for close to twenty days (but I think I can explain that below). Two days later, my brain adapted, and it doesn’t feel that way anymore. And I must confess that I really love to feel the drums kick on my rock tunes, which I sort of discover under a new light with that added kick.
The sub-bass of the SE846 appear somewhat drier in comparison. Not that those of the Ei.XX are bloated, but just that they feel denser. But this may relate to the fact that there is simply more of them with the Ei.XX, or to the fact that I was using Shure Olives, and not silicon flanges (but I can't stand 'em).
Having always considered the SE846 to be bassy iems, so I will say the same about the Ei.XX: they are not for the bass faint, and will clearly show the bass content of your music.

Mids
This is the part which I had the hardest time with. And probably the only thing I can reproach the Ei.XX with, although this is very much a matter of tastes as you will see.
My main beef with the Ei.3 was overall sound purity / lack of crystal-likeness. With the SE846, it quickly was obvious that my main beef would be boredom. They’re a great performing bunch, and I have almost no technical reproach (except for the stretched scene above), but they leave me limp. Like a really hot girl, but one that I just don’t lust for.
Well Ei.XX are different. They make me lust. But they frustrate me a little bit at the same time. They are clearly colored in the mids (I confirmed with Piotr that they are tuned for a “fun signature”), which is nice but leaves me wanting for more neutrality on some of my tracks (think Dire Straits, vocal or acoustic guitar focused songs). But then I’m a neutrality junkie.
I would describe this coloration as W-shaped. I more or less managed to reproduce is by applying a blend of ‘Jazz’ and ‘Rock’ equalization to my SE5, that is with a dip around 500Hz, a peak around 1.5kHz, and another dip around 2.5kHz.
At the very least, one can say that this coloration is clearly audible. During my first sessions, I even had the impression that some of the timbres were off! Apparently, this relates to the fact that the Ei.XX coloration plays exactly in the main frequencies of my Foo Fighters albums. I confirmed this by reversing the above described signature and applying it to the Ei.XX, which gave me more or less the sound I was used to hearing.
Once I felt reassured, I told myself “if you can beat’em, join’em”, and that I might as well try to embrace the Ei.XX mids and see how things went. And you know what? I got used to it. Well almost, because, to be 100% honest, the first time I listened again to my Foo Fighters with my Harmony 8 Pro, if felt like being back home after a looooonng trip.
Nevertheless, I really like the Ei.XX. They are indeed fun, and for a nomadic experience, they make a really great combo with the impact of the bass. It’s simple, pretty and efficient. And darn good with electronic music.
To sum things up, the mids coloration and the bass amount is a clear departure from the traditional Custom Art house sound. The Ei.XX are not strangers, but they’re more like cousins than siblings (sorry for the lousy metaphor).
Most of all, the mids are not lacking in presence, which almost surprised me when you see the added bass and sub-bass, as well as treble.
I was worried that mids would be somewhat lacking, but it is definitely not the case from my sessions. You could, on some tracks, find that the voices are a little laidback (think Mark Knopfler on ‘
Telegraph Road’). But that’s really being picky imho.

Trebles
The part of the Ei.XX which gave me the most satisfaction at first. The only beef I had with Ei.3 is clearly fixed. Highs are here, they’re pretty, my cymbals finally sound right. They are not fatiguing to me, but then I am apparently impervious to treble fatigue and sibilance.
The trebles have clearly inherited some of the coloration from the mids, and this can be felt on some cymbals. But at the same time, they provide so much detail, they perform with such an incredible precision without ever being tiring!!!
I insist here, because the SE846 have the reputation (which I was able to confirm) of being excellent performs in that field, yet the Ei.XX are clearly a notch above in my book. However, you should not expect the Ei.XX trebles to provide the air of that of the SE846. The Ei.XX really are more on the warmer side, yet with incredibly present, precise yet soft highs. And yes, I am aware that this will sound paradoxical (I could use more derogatory words here but then who needs to constantly invoke bovarian faeces?).
Conclusion
The Ei.XX appear to be a fun bit of ciems. They have strong bass engagement with a great scene, very good details and separation.
Build quality and fit are top notch, but hey, let’s be serious, anything less would now be a disappointment coming from Piotr.
Before you take the plunge, please take into account the fact that Ei.XX are NOT neutral. For all their qualities, if neutrality is your dope, then they’re probably not for you.
In my experience, they really play toe-to-toe with the SE846 technically speaking, and the choice between these guys really appears to be a matter of taste. And maybe a little bit a matter of money too, because the Ei.XX have a $600 price tag which is much lower than that of the SE846, with the added advantage of being custom molded.

[size=20.007px]The Ei.3 / Ei.XX / SE846 Truel[/size]
For dessert, I thought I’d provide you with a detailed comparison of the Ei.3, Ei.XX and SE846 on tracks I have listened to at least 400 times. The comparison was made on my iPhone 6 connected to the Headstage Arrow 5TX, mainly because I find the iPhone 6 lacks a little bit of bass authority. And also because the Arrow 5TX has a clicking soundwheel, which is super cool for volume matching (as I wrote above, I used two clicks between the Ei.XX and the SE846, the latter being the louder of the two).
The part concerning the Ei.3 as well as the ‘What to look for’ where inherited from my Ei.3 review. The order of presentation corresponds to the order in which I took my notes, and I listened pseudo-alternatively-randomly to the SE846 or to the Ei.XX first on each track.
Iggy Azalea – The new classic – Black widow
What to look for: sub-bass and their cuts (starting at 1’50)
Ei.3: subs are well established, a constant tense humming which cuts sharply and resumes with the following « boom ».
Ei.XX: welcome to a new sub-bass world. It’s not a humming anymore, but a tight and thick vibration !
SE846: sub-bass are close to that of the Ei.XX, but a little less thick, a little drier and less present.
Daft Punk – Random Access Memories – Doin’ it right
What to look for: sub-bass.
Ei.3: clean engaging subs. Not the biggest soundstage ever, but the job is done nicely and it just sounds right.
Ei.XX: the sub-bass provide impacting booms, and the quality of separation of the Ei.XX really makes the details shine (like the bell around 1’50)
SE846: a different interpretation due to the contrast between the coloured Ei.XX and the more neutral SE846. I prefer the latter because of the airier and ‘straighter’ restitution fo the SE846. But they don’t make the details shine as the Ei.XX do, and for instance, you have to know that the bell is here in order to hear it.
Daft Punk – Random Access Memories – Contact
What to look for: all of the song. It goes crescendo all along, just the way I like it. The drums are very important, as they are recorded, but mixed with deep resonating booms and with saturated samples, as well as with a bass line which drives the final climax starting at 2’47.
Ei.3: it is balanced, punchy and dynamic. All of the above is there, without any interference or disappearing, even if depth is somewhat lacking. The experience remains exhilarating to me, due to the unity rendered by Ei.3. The volume knob goes up and up and up, to unreasonable levels.
Ei.XX: it’s a little more intense than with the Ei.3 due to the added bass and sub-bass. I find the drums a little laidback, especially the toms. A little too much bass for my taste, and a little less foot tapping too.
SE846: it’s more balanced, and I like it better. Here again, less details, but it’s not as bothering as with ‘
Doin’ it right’. As usual with the SE846, it remains a little too polite for my taste.
Savant – Alchemist – Fat Cat Shuffle
What to look for: bass texture, spacialisation, bass deflagrations ( starting at1’18).
Ei.3: bass are precise, and their texture is excellent. The deflagrations of the bass beats leave a loud hum but never bleed. They also cut sharply when called for. The whole is very lively, in spite of so-
so cymbals and a shallow soundstage.
Ei.XX: here again, we enter a new dimension. It’s dense, almost fat, but without ever losing control. Probably one of the tunes which suits best the Ei.XX signature.
SE846: the bass are less textured and dense than with the Ei.XX. The overall restitution feels good, but the SE846 are just too goody two-shoes for this tune.
The Avener – The wanderings of the Avener – Lonely Boy
What to look for: guitar clarity, echo depth at 1’00, attack at the beginning, quality of hand clapping
Ei.3: guitars could be sharper, purer, but they’re still quite good. The bass line is really nice and well cut starting at 1’00, with a good depth by Ei.3 measures. Guitars sound a little matte as opposed to crystalline (as an acoustic guitar should sound). Globally not technically optimal (the voice is for example purer on SM64 with more echo depth but similar width, see 2’27), but it sounds incredibly well overall.
Ei.XX: the attack could be a little stronger. The guitar is clear, but it could be clearer (should be). The soundstage is nice, with a superb echo depth. The beat shows a little more authority than with the SE846.
SE846: this tune was made for them. All is just great. The guitar shines, and the restitution really benefits from the SE846 airier restitution. At 1’55, the specialization effects are more natural than on the Ei.XX, but the echoes show that the soundstage is significantly shallower.
The Avener – The wanderings of the Avener - Castle in the snow
What to look for: grain of voice, echoes (drums at 1’00), voice depth all along, for example at 2’41. Ability to smoothly mix original song with added electronic samples.
Ei.3: very musical, not overly spacious compared to SM64. The shallowness of Ei.3 soundstage shows. However, the width of the soundstage makes up for it at 2’41.
Ei.XX: I don’t feel I ever truly felt the depth of this tune before, and certainly not with such ease ! It’s ample and beautiful, details overflowing yet musical at the same time. The beat imposes the rhythm and you can’t help but tap that foot. Wow.
SE846: ouch. The lack of depth shows immediately, and it stings. The beat is less present. Nice, but it doesn’t quite cut it after the Ei.XX.
The Avener – The wanderings of the Avener – To let myself go featuring Ane Brun
What to look for: acoustic guitar, beat, musicality (violins at 2’25).
Ei.3: guitars are not as nice as with SM64. Likely due to Ei.3 cutting high too quick. But the more upfront soundstage and the mids density makes it all fun and games.
Ei.XX: if I was allowed only one word, ‘fun’. The beat is strong with this one, you can see the sub-bass at work. It even highjacks the guitar a little. The violins are here, but they’re not the stars of the show. Overall very dance-inducing and musical.
SE846: a little more balanced. It lacks a little depth and the beat is less present, but that gives more room to the rest of the tune. With just a little beat, it would have been perfect!
Dr DRE – 2001 – Still D.R.E
What to look for: flow, impact
Ei.3: FAST, make you want to bobble your head.
Ei.XX: boy this is fun. The beat hits you, the voices are right where they should be, and my head is bobbling. Really great, even though it would have been even greater without the coloration which changes Dre’s voice. Matter of taste though if you’ll ask me.
SE846: the strings are nice, but they just take too much space compared to Dre’s voice: they’re in front! Snoop sounds better, but overall, it’s very disappointing.
Foo Fighters – Wasting Light – Rope
What to look for: bass line (rare item to look for in Foo Fighters), doubled voices (big feature of Wasting Light album), chorus, and the cowbell at 2’55. For cowbell amateurs:
Ei.3: bass line is precise, could be a tad more upfront. But boy it does the job right, be it for driving the chorus or for driving the instrumental parts prior to the doubled voices. The second voice, higher, is a little less readable, but it all sounds so well together. The cymbals are there, but more as a concept, as they lack precision: the impact is there, but there resonance is much (way) too short. The cowbell is clean but somewhat shy.
Ei.XX: bass line is top notch, and the drums kick like I’ve never felt it kick before (probably the Ei.XX greatest quality on rock music imho). I’m still bothered by the mids coloration, which makes some guitars and toms sound a little weird for my taste. But once you get accustomed to it, boy it’s fun!
SE846: the bass line could use a little more strength, but the rest is really clean and fun. I find the sound of the tune that I know. But I must confess, it’s a little less fun than with the Ei.XX.
Foo Fighters – Wasting Light – Dear Rosemary
What to look for: the intro, which echoes the end of the previous track (“Rope”), the little bells, the stop and block created by the drums and guitars, the doubled voices starting at 0’50, including on the chorus, the rise starting at 3’04.
Ei.3: engaging intro, very so-so little bells. Drums play their role perfectly, and provide a strong rythmic sense. The voices combine perfectly, and it sticks up with you, but in a good way. The final rise really makes you want to shake your head and to pump up the volume. Ei.3 really do this tune justice.
Ei.XX: if you forget the mids coloration, as with ‘Rope’, it’s top notch. All is technically irreproachable, from the bass to the guitar including the drums and the little bells. The voices are perfectly separated, yet totally sound in unison! Eargasm.
SE846: the classic difference with the Ei.XX – the bass is less present, there is less details and the separation suffers from it (think doubled voices), but an overall super-duper clean restitution. A bit less engaging, but truer to the sound I know from that tune.
Foo Fighters – Wasting Light – Arlandria
What to look for: in the beginning, the echo of the scratched guitar rythmic part, the separate guitar parts at 1’30 (scratched on the left, melodic on the right), the little bells and the doubled voices on the chorus, the bass echo which moves from left to right and back between 3’12 and 3’36 ; the tom triplets (see 2’14, 4’02 or 4’18).
Ei.3: in the intro, the scratched rythmic resonates in the depth direction at the center. The drums and the frontal scene induce instant foot tapping despite the lack luster little bells. The melodic guitar on the right lacks purity, crystal sound. The whole is really fun thanks to the drums.
Ei.XX: the doubled voices are incredible, and so are the little bells. Too colored again, but it’s less bothering here. Bass echoes and drum triplets are awesome.
SE846: the voices and details are somewhat less satisfying. Bass echoes lack a little depth but drum triplets shine.
Foo Fighters – Wasting Light – Walk
What to look for: all of it. Again a tune which goes crescendo in intensity. First, melodic guitars which are lateralised, then the bass tom, the rest of the drums, and the little bells before the 2’05 break. And it starts again crescendo at 2’45, adding an instrument with each repetition. Several end teasings before the drum finish circa 4’02.
Ei.3: this tune sums up the essence of my Ei.3 experience. Not the most perfect technically, but it grabs you by the guts, and I pump up the volume knob to unreasonable levels (fortunately not for too long).
Ei.XX: wow dat bass drum ! Seriously dat bass drum ! It hits hard, it rises, taking you away…
SE846: about the same thing, with less bass drum, details and coloration. Eargasmic.
List of tracks used in the test list:
2 Cellos – Celloverse – The trooper (overture)
Toby Lightman – Little things – Devils and angels
Minerals – White tones – Last time
Radiohead – The king of limbs – Feral
Monika Borzym – My place – Finding her way
Brahms- Ein deutsches requiem Op.45-Selig sind die da Lied tragen-, Chorus
Com Truise – Galactic melt – Futureworld
Daft Punk – Random access memories – Contact
Matt & Toby – Matt & toby – Good boys
Dire Straits – Love over gold – Telegraph road
Dire Straits – On every street – On every street
Monika Borzym – My place – Pisces
Lights – Siberia – Flux and flow
Toby Lightman – Little things – Real love
Korn – Take a look in the mirror – Play me
Massive attack – Mezzanine – Angel
MDC – Conception – Good vibes
Alicia Keys –The diary of Alicia Keys – Nobody not really
Hans Zimmer – Pirates of the caribbean dead man's chest – Jack Sparrow
Christina Aguilera – Save me from myself – Save me from myself
Drydeck – DDK VS ODG /2 – Gentle RMX
The Killers – Hot fuss – Mr. Brightside
Savant – Alchemist – Fat cat shuffle
Pandadub – Archives – Myopie