CustomArt Ei.XX 6-driver CIEM - MassDrop edition

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CustomArt Ei.xx

 

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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).
 

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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.
 

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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.
 
 
 
 
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

 

 

 


Disclaimer:
 
i am a CIEM freak who went CIEM over full size headphones, and i use the CIEMs on my desktop, not portable, CIEMs have come a long way that i made them my main setup, this review is to show you the full potential of the Ei.XX with the best Portable Rig, and will be tested with few cables which i find them one of the best.
 
and oh my English Writing isn't super so bear with me if you saw a mistake here and there  

The Equipment:
 
i am using Hugo Chord as a DAC and for the amp i am using the amp section of the Hugo, since this a review for a portable rig its better to stick with dac/amp setup, not a dac + amp fat rig setup, for the cables i testing with the stock cable, Toxic Cable Scorpion and Toxic Cable Silver Widow 22.
 

The Craft and Fit:
 

 
I had few CIEMs before, UM Miracle , UM Mentor, and Custom Art Anzu v3 (crafted by Lear Ear) and my ear impressions were very very good, i went for the best option in Dubai Mall's Clinic, i was always happy with my CIEMs, used them for hours.
 
yet when i received my Anzu V2 and Ei.XX from Peter. i was shocked, they look very nice, and fits like a glove, and from the first day too!!, usually you about people complaining on the first few days, even i did with all my previous CIEMs, not that i did complain a lot, but i felt small annoying feeling on the left ear, and this feeling goes away in 2-3 days

but when it comes to Peter's CIEMs, never i felt annoyed nor found them hard or semi annoying to be removed, they fit like a glove, and easy to remove and insert, simply shocking, easily the best CIEM craft i ever encountered since 2012.

Sound impressions:
 
Bass:
 
the bass is rumbling!! i though for a second that it had a Dynamic driver, but no it was a Balanced Armature driver, wow Peter, not sure how he did manage to do this, its also fast, a great mix between the rumbling of a Dynamic driver and a fast Balanced Armature driver, yet fear not! the bass doesn't bleed into the mids, what a great balance, the sub bass is great too! 
 
i also wanted to note that i didn't find any problem with the Bass Texture, remember i am using Hugo Chord and Toxic Cables here to see what the Ei.xx is capable of, and i can safely say that both slam, speed and texture are ultra epic!! so if you went with a high end rig, fear not, the Ei.xx's bass will keep scaling with your rig
 
Mids:
 
WoW, i am glad i went with this CIEM over the SE846, i used to think that boosted thick mids are the best, when i look for mids, my collection is 99% got female vocals, the mids are really super important for me, i had SE535 and tested my friend's Se846, yet the Ei.xx's mids won me over.
 
why? its placed right, its still dense and will satisfy your mids/vocal needs, its organic, lush, and creamy to the max, in fact i had WA7tp before, and used it to make the Mentor Mids sound creamy and lushy, since the Hugo Chord alone wasn't able to achieve that with the UM Mentor, yet here comes the Ei.XX, simply wow, its so sweet i feel like melting while listening to its mids.

The placement of the Ei.XX is right, its not forward, nor back, which will make you enjoy the mids while not craving V-Shaped sound sig CIEMs, i find myself to miss my Anzu v2 CIEM when i am using the SE846, feeling like i want more bass/treble presentation, yet using the Ei.xx didn't make feel so, it was the right/perfect balance between fun and sweet organic mids, placed int the right way to make you enjoy a super mixture that will produce nothing but a smile on your face and a tapping feet that want to dance from the fun.

Treble:
for a "crazy" Treble head like me, the Ei.XX was a unique case, it wasn't sibilance at all!! i got this one track, little badly recorded, and tested the Ei.XX on it, this was my first CIEM to not sound sibilance on this track, and on my Hugo Chord and stock cable, the Treble wasn't really falling back, yet more sparkle and extension would have helped, but again i am a Treble head who listen to J-pop, so the others will find the treble fine. 
 
Cables: 
 
Toxic Cable Scorpion:
 

 

 
this is a HQ copper cable, compared to the stock cable it had smoother and less airy Treble, so for me or anyone who don't want less Treble , stay away from any copper cable, yet on the other hand the mids gain slight lush and warmness, and the bass impact went deeper, not bad, yet the price was the Treble Extension here, and it wasn't as fun because of that, at least for me who care about the Treble, if you don't then give a good copper cable a try, its all about preference in the end.

Toxic Cable Silver Widow 22:
 

 

 
the Silver Widow is a OCC Stranded Litz Silver with Gold/Cryo cable, one of my favorite cables, this one brought the Ei.xx potential to crazy, the Treble airiness and extension became enough for me to move my head right and left when listening to pop, while enjoying the creamy organic mids.
 
thanks to SW22's smoothness the whole music got even smoother, yet still fun and enough for you to enjoy the bass and treble a lot while maintaining the mids quality, the bass might been slightly less on the impact compared to copper, but the details, micro details, bass texture and speed went epic, also the SW22 got stronger bass impact when compared to pure silver cables, which is why i went with it for my ei.xx.

Which Cable should you go for?
 
don't get me wrong, you don't need to spend more to make the ei.xx sounds better!! it already sound really good!!, but this head-fi were some of us like to improve the sound and they are crazy with this hobby, yet if you want to spend little extra i suggest a silver cable, since it will bring the Treble Extension with slight bass impact decrease, but don't get me wrong the silver is clear and smooth, fast with better bass texture.

Why the Ei.XX over other Similar CIEMs?
 
now if you want a in your face boosted mids, which is not bad i used to enjoy the SE series for this alone! and you don't mind losing some lush/warm/sweet organic mid, then the SE series is the way to go, but keep in mind the Treble/Bass presentation will be way different than the Typical  U shaped sound sig
 
yet if you want to maintain the fun of the Bass while wanted Organic Creamy Mids, then there is no other option than the Ei.XX, it will fit the bill 100%. 

Why the Ei.XX over U shaped sound sig CIEMs?
 
U shaped sound sig CIEMs, sound darn fun!! but the mids are falling back, and not smooth or organic, the Ei.XX bring something new to the table when offering both fun and creamy mids, its one of a kind.
 
yet if you don't mind the mids to sound on the Neutral side,  and wanted bass/treble fun, then the NT6pro or NT6 and similar CIEMs is what you should go with, remember its all about what sound sig you want, not about the hype, so make sure you pick what you want, not what the most want.
 
Conclusion:
 
The Ei.xx is a perfect combination between fun, and nice organic lush mids, which is a rare case when it comes to CIEMs, never i though i will see a similar CIEM but again Peter proves that he is a Genius that keep adding more unique products to his company, not to mention the value when we compared it with more expensive CIEMs out there, and thanks to peter's tuning they scale up with high end rigs to make them sound perfect and almost all in one whole package. 
 
 
P.S: sorry English isn't my first language, and i am sure i got a lot of Grammar mistakes over there -.-''  

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Before I start my writeup, I would like to Thank CustomArt (@piotrus-g) and MassDrop for the opportunity to review a product of their exclusive collaboration, Ei.xx CIEM which I received in exchange for my honest opinion.
 
Due to exclusivity of this Special Edition CIEM version, keep checking their direct listing link on MD: https://www.massdrop.com/buy/customart-massdrop-exclusive-ei-xx-ciem which should go Live again in the next round of Drop.

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Often when I approach a company with a request for review or the other way around when I'm being approached by a company, I do my homework to learn more about their product and their reputation.  When MassDrop reached out to me with a request to review their upcoming featured product, I was intrigued and excited about the opportunity.  After being told it’s an exclusive CIEM from the Custom Art, I sharpened my pencil and got right to work!  My “homework” led me to a single name that got a lot of praises from everybody - Piotr, the man behind Custom Art.  As I started my communication with him in prep for this CIEM, I quickly realized how passionate and knowledgeable he is about multi-driver design, and why so many people, including such a popular e-commerce site as MassDrop, put their trust in him.
 
Still in his mid 20th, within short period of time Piotr evolved from Head-fi visitor and reviewer to someone who took his passion for Custom IEM into his own hands to start a company and to go against established “dinosaurs” in this segment of audio gear market.  It was definitely a bold move considering his operation is from Eastern Europe (Poland), though with an advantage of being vertically integrated where everything is being done efficiently in one location once he receives your impression, even to the point of requesting to send impression pictures prior to the actual shipment.  Piotr wants to be sure you don’t waste your time in case if impressions don’t meet his expectations.  Custom in-ear monitors (CIEM) require a special attention in order to make them sound and look great, not just a clever configuration and tuning of the drivers but also skills to take a custom impression of your ears, made by a local audiologist, and to turn it into a shell mold designed specifically for your inner ear footprint.  It's very impressive to be able to accomplish all these steps from sound design to shell manufacturing, and to be able to have many dedicated fans and loyal customers who speak volumes about his products.
 
Due to expedited schedule in lieu of MassDrop release deadline, I received my Ei.xx review sample lighting fast, but typically you should expect to wait about 4 weeks which is normal with other CIEM manufacturers as well.  Obviously, CIEMs could be customized per your design requirements (shell color, material transparency, faceplate and artwork, cables, etc.), but you should still expect with every order a common packaging with a genuine Pelican 1010 compact case to protect your headphones during shipment and also during everyday transportation.  Inside of the case you will find Ei.xx CIEMs with an attached cable, a cleaning tool, and a personalized warranty card with a hand written date of when CIEM was manufactured and a printed acknowledgement that you have 12-month warranty.  As a matter of fact, you also get 30-day fitment warranty in case if something needs to be adjusted.  Even custom impressions are not bulletproof, depending on a technique and a material used by your audiologist or the process during manufacturing of the earpiece mold.  Remember, Piotr and his team will have to trim the mold to a desired shape, allowing some marginal room so it will feel comfortable in your ears.
 
Unboxing.
 
 
 
 
Due to a cable being removable, I always consider it as one of the accessories, especially since you have an option to stay with a default one or to select another one when placing an order.  Or you can upgrade it later with aftermarket cables since majority of CIEMs use two common connectors: 2-pin header or mmxc connector.
 
Though a stock cable included with Ei.xx is a generic OFC type, I actually found it to be of a good quality.  To match the color scheme of my blue translucent CIEM, the cable I received had silver looking wiring with a clear shielding, soft and easy to manage for storage, and hardly any microphonics.  The right angle 3.5mm connector, y-cable capsule, and chin slider all had a matching soft plasticy material with a cloudy white semi-translucent finish.  2-pin standard connector was used, and a portion of the cable next to the connector had a memory wire.
 
Stock cable.
 
 
 
 
On a subject of replacement cables, one of the offered options with Ei.xx order is Linum BaX.  Since I already have one, I decided to run a test to compare it against the stock cable, and also to throw in the mix my TWag v3 cable.  In my testing of Ei.xx with Stock vs Linum BaX, I'm hearing a definitive level of refinement, especially in retrieval of details.  It even felt like a faint layer of veil was lifted off.  With my Whiplash TWag v3 pure silver cable, I hear more changes, making sound a little more forward (especially with vocals), brighter and more balanced in comparison to a stock cable which has a warmer and more v-shaped sig.  For my personal taste and using a selection of low output impedance DAPs as a source, pure silver cable didn't compliment sound signature of Ei.xx to its full smooth potential.  With BaX the change was not as drastic but more of a refinement, especially with detail retrieval and some improvement in low end quality.  It's all a matter of personal taste, and I would suggest to get used to a sound with a stock cable first before you move on to an upgrade.
 
With different cables (Stock, Linum BaX, Whiplash TWag v3).
 
 
 
 
From what I learned, Piotr originally started with silicone as his exclusive CIEM material, but later with Ei.3 and this new Ei.xx model he decided to use a more common acrylic material which is easier to deal with during mass production.  I’m not gonna lie to you, my vast experience with in-ear headphones is based on universal fit models, and Ei.xx is only my 3rd CIEM.  But regardless of this limited experience, I can still see a great quality of workmanship.  A baby-blue translucent shell finish of the Ei.xx I received was quite revealing since you can see everything inside out, and I didn’t find any noticeable blemishes or bubbles worth mentioning.  I only had one comment about the area of the connector socket that looked kind of partitioned, but if I would have a darker or a solid color shell and a non-transparent faceplate – this wouldn’t be even visible.
 
I was actually pleased to be able to see every single driver, every single wire, sound tubes and filters, and all other details inside of the shell.  With 6 drivers, partitioned into 2 super lows, 2 lows, 1 tweeter, and 1 super tweeter – you can see how 4 bass drivers are grouped together going to one sound tube path up to a nozzle bore with a green filter, and 2 tweeters grouped together and going to another sound tube path up to a 2nd nozzle bore with a white filter.  Cleverly, Piotr used Red wires inside of the Right earpiece, as well as the red label with serial number on outside of that shell on the right side and blue label on the left shell.  Obviously, Left and Right earpieces are not symmetrical and you won’t be able to jam a wrong one in your ear by mistake, but I still find it helpful to be able to distinguish the sides prior to placing them in my ear.
 
Design details.
 
 
 
 

 
It’s always fascinating to examine CIEMs in our hand, but the next step is very crucial – the fitment.  No matter how great is the tuning of a sound, if the shell doesn’t feel comfortable inside of your ear, you are not going to enjoy it or get a proper seal to appreciate full frequency content.  I was a bit nervous putting Ei.xx first time in my ears, but to my pleasant surprise the fitment was like a glove perfect!  With a typical clockwise movement they went into my ears smoothly and formed a good seal which stayed intact even when I open my mouth.  Sound isolation was also very good.
 
Fitment.
 

 
Sound Analysis.
 
After confirmation of the fitment, I was ready to start my sound evaluation.  Since I don’t have any previous experience with other Custom Art CIEMs, I wasn't familiar with their house sound and didn't know what to expect.  But knowing that I’m dealing with 4 dedicated bass drivers and 2 dedicated tweeters, I was already anticipating great things from the low end!
 
With hours of careful listening, I found Ei.xx to have a smooth detailed sound with organic tonality and enhanced low end impact which contributes to a slightly v-shaped signature.  Here is my sound analysis in more details.
 
Considering 4 dedicated bass drivers, 2 super lows + 2 lows, you can take a wild guess that bass is a star in these CIEMs.  Ei.xx low end is very articulate, tight, well controlled, with a deep textured sub-bass rumble that is not just great in quality but also in quantity, and at the same time perfectly balanced with a fast mid-bass punch.  In this case I'm “hearing” low end performance like a hybrid combination typical of dynamic driver longer decay (down in sub-bass area) and a fast BA punch with a short attack (in accentuated mid-bass).  There is a very slight bleed into lower mids, but it doesn't contribute to any muddiness.  With such attention to low end details I don't want people to think Ei.xx is a basshead CIEM, but for sure it will be highly appreciated by anybody who craves high quality articulate bass impact.  If you are a fan of SE846 and UM Pro 50 bass - Ei.xx will be not just your cup of tea, but the whole kettle!!!
 
Lower mids presence is not too thin or too thick, sharing a little bit of warmth from the low end which adds some body to a sound.  Upper mids are smooth, detailed, and very organic.  They are not analytical or micro-detailed, but they do have a good level of clear detail retrieval while still remaining smooth and natural, especially with vocals (both male and female) that shine through with a clean timbre.  I usually trust my ears over FR measurements, but was curious to see Ei.xx FR graph where I found a slightly scooped mids around 500Hz-1kHz which explains why mids sound a bit recessed.  You have 4 drivers dedicated to low end and 2 dedicate to top end, and the valley of that scoop actually partitions low end and top end into their own separate domains where you can shift listening "focus" from one to the other.  I actually found this slight scoop to enhance the dynamic impact of the bass and to improve the clarity of upper mids. 
 
Despite 2 dedicated tweeters, I found their sound tuning to be shifted more toward upper mids and lower treble range.  Treble is smooth and detailed, not extra crisp or super "hi-def" extended, and also lacking some airiness.  But at the same time it has a rather good definition, and absolutely NO sibilance which is fantastic for extended listening sessions.  I threw at Ei.xx all my sibilant test tracks, and it passed the test with flying colors.
 
Separation of a sound in these headphones is good, with a clear layering between vocals and instruments, preventing congestion of a sound.  I was also impressed with a soundstage expansion, definitely way above the average.  Actually, I'm hearing more width and height than depth.  To my ears, placement of instruments and vocals was not exactly 3D in space, but it still had a very convincing natural imaging with some intimacy.  This type of imaging along with a smooth detailed sound would make Ei.xx not only great for audiophiles and casual sound enthusiast, but also for performing artists to use these CIEMs as monitors on stage, which is great for extended listening in any environment due to a great isolation and very comfortable fitment.
 
When it comes to pairing, I'm not going to talk about every single DAP I tried it with because I have way too many of them.  But one thing I found in common - a warm smooth signature won't benefit from a warm sound source which can make sound more congested and less detailed.  I found Ei.xx to pair up better with neutral and brighter sources.  No amping was necessary, and due to sensitivity you will enjoy these better with sources that offer a solid black background.
 
Comparison to W60, W50, UM Pro 50, DITA (Whiplash cable mod), InEarz P650, and SE846.
 

 
In comparison to some of my other IEMs, here is what I found.
 
Ei.xx vs P650 - P650 has a very similar soundstage expansion, sub-bass doesn't extend as deep and has lower quantity, mid-bass punch is not as tight and overall bass is slower and lower in quantity, and not as well controlled.  Lower mids are a bit thinner, while upper mids are a little more upfront.  Treble is slightly better with a little more brightness and airiness.  While fitment should be similar (due to impression from the same audiologist), P650 felt a little less comfortable in comparison to CA.
 
Ei.xx vs SE846 (going by memory when I had a loaner, while I took good notes) - 846 low end is very similar in terms of the impact, speed, and overall emphasis.  Ei extends deeper with a more noticeable sub-bass quantity.  Also, Ei mids are more organic and smoother, while SE846 mids are more in your face, brighter, and a bit harsher to my ears.  SE treble has more airiness, more sparkle, while Ei is smoother and not as extended.  Soundstage is similar.
 
Ei.xx vs UM Pro 50 - Pro50 soundstage has less width, mid-bass punch is very similar, but Pro 50 sub-bass doesn't extend as deep and doesn't have the same level of rumble, and feels a bit scaled down in comparison.  Lower mids in Pro 50 are warmer/thicker, while Pro 50 upper mids are similarly smooth and organic, and maybe a touch brighter.  Treble in Pro 50 is a bit brighter, has a similar definition, and a little more airiness.
 
Ei.xx vs W60 - W60 has a similar soundstage expansion, bass is less aggressive, more laid back (slower attack), and less quantity.  Similar low end extension, though Ei feels like it goes a bit deeper, and the mid-bass punch is tighter and better controlled.  Lower mids are very similar, while upper mids in W60 are more detailed, have more natural tonality, and a little more upfront.  Treble is very similar.
 
Ei.xx vs W50 - W50 has a touch narrower soundstage, very similar low end quantity with a similar deep sub-bass extension and slower mid-bass punch.  Actually, W50 bass sounds looser and even a bit muddy, not as articulate.  Mids are warmer and thicker, not as detailed, while treble is similar.
 
Ei.xx vs DITA (silver gold re-cabled, original sig is changed) - DITAs soundstage is a bit wider, sub-bass has a similar extension but less quantity, mid-bass is not as punchy or as fast, sounds slower.  Low end is not as tight or well defined, too relaxed and lower in quantity, lower mids are similar, but upper mids are a bit more recessed and brighter in comparison, treble is brighter, more airy, with a better extension.
 
Conclusion.
 
IMHO when you are dealing with a quality $500+ multi-driver IEMs/CIEMs, it’s no longer about sorting out “bad” vs “good”, but rather about discovering different sound signatures to determine which one you enjoy better or which one comes closer to your preference of TOTL end-game sound.  The more headphones I review, the more I realize that TOTL “end-game” sound encapsulated in one pair of headphones might not be realistic.  Not necessary because it’s not possible, but rather because I end up craving two types of sounds (Yin-Yang): a smoother/warmer/organic with more bass impact and a more neutral/brighter/revealing with a more balanced signature.  It all depends on my mood, on the type of songs I’m listening to, and the sound signature of sources I'm using.  To my ears Ei.xx sounds like a love child of SE846/UMPro50 (low end impact) and W60 (organic detailed smoothness of mids).  It definitely takes Yin to perfection and makes it one of the new reference standards in my book when comparing bass quality and quantity, along with a smooth detailed organic mids/treble.  I might be still on a journey to find my Yang where most of the revealing IEMs I tested had some harsh peaks (subjective to my ears), but in case of Yin I found Ei.xx to hit it hard with a bass impact like a jolt of energy!  Well done Custom Art, well done Piotr!  I'm looking forward to your next masterpiece, perhaps something that can bring my Yin and Yang closer together under one roof (or in one shell).