After reviewing the IKKO OH1 that Patrick sent for review, I was interested in their newest release the OH10.  I bought the OH10 outright so no disclaimer is needed.    If you have an interest in IKKO products, please visit their website, or facebook.  IKKO products can be purchased from Amazon here or purchased from Xtenik here.

Unboxing / Packaging:
The packaging of the OH-10 shows IKKO’s style with the anime character on the front, and the details on reverse.  Even the sides of the box are adorned with either product photos or specs.  (My understanding is the misspelling of hybrid has since been corrected).  Removing the slip-cover reveals a black book fold box with the earpieces resting in a velvet covered foam tray.  Lifting the tab at top reveals a second compartment with tips held nicely in their own foam block, a leather mat to prevent scratching the earpieces, and an IKKO Lapel pin nestled in foam padding.  The cable and carrying pouch are hidden inside the leather mat.   Overall, the kit is what I would expect from a build at this price point as we are approaching the $200 mark.   Some models at this price provide a hard shell case and if you prefer one, you’ll want to add that at checkout as only the soft case is provided.  The soft case is thought out well with 2 pockets to allow separating the earpieces to prevent scratches while in transit.   Two sets of tips are provided (neutral and bass enhanced although no documentation of such).  The block the tips are stored in is a nice touch, but would be appreciated more if it fit in the travel case perhaps.

The first two pictures below were gratiously provided by patrick of the copper alloy shell before final plating.  This is one of the hallmarks of the OH-10, so I wanted to show it off.   Due to some proprietary techniques and design of the internal cavity, I won’t be able to share the inside of the cavity.   The Shells are nearly exactly the same shape and size as that of the OH-1 but heft is dramatically different.  The OH-10 weighs in at a bit over double that of the OH-1.  The .78mm bi-pin connector is slightly elevated above the shell but is not the hooded type that has become popular of late.  Vents exist on the inner surface behind the nozzle and on the upper surface near the mid-point of the shell.  Nozzles exit the front of the earpiece with an upward rake and a pronounced lip to hold tips in place (standard T400 tips).  The seam between faceplate and shell is not hidden, but polish is very good with no crisp edges anywhere on the unit and mirror finish throughout.

The OH-10 is powered by a pair of drivers, one. 10mm dynamic and one balanced armature.   The dynamic is a dual diaphragm titanium coated polymer model, while the balanced armature used is a Knowles 33518.   Worth noting is the copper alloy shell was designed with an acoustic chamber specifically for this 10mm driver so a lot of work went into reducing harmonics and producing the best sound possible from the drivers.  I note this as I think the same driver in a different shell might not show the same level of refinement as a lot of work went into the pairing of materials.  Nominal impedance is listed as 18Ω with a sensitivity of 106dB/mW.   I found the OH-10 to be reasonably well driven with a phone or a tablet, but it does scale well and detail improves considerably with a better source.  This is a case of scaling in quality rather than quantity as a phone is capable of powering it fully.

The provided cable is a standard length (1.2m) made with 4 strands of 5N oxygen free silver-plated copper with a black outer coating.  From the 90º Jack, the cable exits through a proper strain relief as a double twist pattern (two wires paired, then the pairs wrapped).  The splitter is a metal barrel that matches the earpieces closely.  Cables exit as twisted pair but not as tightly as below the splitter.  Pre-formed earhooks are provided without memory wire and terminations are metal encased (again matching the earpieces) .78mm bi-pin connectors.  The right connector has a red ring around it for quick identification.  The earpieces themselves do not identify R/L but only fit one way so matching them up is a pretty straight forward proposition.  The cable has a leather cable tie provided that matches the protective mat.   Again, a nice touch to make all the cable parts closely match the earpieces and accessory kit.

There are 2 sets of 3 sizes of tips provided (SML).   They are all silicone, but of two different designs.  I found the narrower bore to be a bit nearer to neutral (not that the OH-10 is ever that) while the wider bore enhanced bass response mildly.  The OH-10 has plenty of bass for my tastes with the standard tips so I stuck with the narrower tips for my sound notes and testing.   Again your views may vary based on tip selection.


The OH-10 starts off with a mildly emphasized and well extended sub-bass which gives it a satisfying rumble.  If you have used the OH-1, the OH-10 has the same level of control over the bass,  with added umph.  Lower mid-bass is mildly emphasized and falls as it moves toward the mids.  Again control is very good and texture is above average.   The OH-10 is best used at lower volumes as the control over the bass seems to lessen as volumes increase and if listening at above about 80dB some congestion can appear in more complex tracks.  Backing off the volume a bit restores control and the congestion disappears again.    Some mild-mid bass bleed occurs and while it does not obscure the mids, it does provide a bit of warmth to the signature.

Lower mids are the mildly recessed but not lacking in detail.  As we move up, the mids move forward and female vocals present in front of their male counterparts as a result.  Timbre of electric guitar is realistic with good growl which makes the OH-10 a fun listen for rock and classic rock.   I found the clarity of the mids to be probably the most impressive thing about the OH-10.  That doesn’t mean I found the mids to be accentuated the most, just that despite starting out slightly recessed, the definition and textures are very clean and precise.   If anything, if you could retain the quality of the mids and push the lower mids just slightly forward it would be near perfect for jazz as well.

Lower treble is emphasized but drops fairly rapidly as you move further up creating a signature that has good clarity while avoiding any tendency to get strident.  The bright tilt makes high hats and snare with brushes sound particularly clear and realistic which is no easy task, while cymbals fall just a hair short of sounding lifelike.   The roll-off of the upper treble probably limits the cymbals a bit, but does also make the OH-10 less fatiguing than many with more high end emphasis.    The most treble sensitive among us may find the OH-10 to be fatiguing, but for the rest of us, the detail, clarity, and air this provides will outweigh any aversion to bright signatures (yes, its that good).

Soundstage / Imaging:
Stage is good sized with a touch more width than depth.  I found the stage was large enough that orchestral pieces were seated properly with nothing behind that should be next to or vice versa.   Imaging is very good with directional cues and movements being well represented as well.   Layering is good with the caveat that the bass gets a touch loose as volumes increase and the OH-10 is best listened to at moderate volumes.   I suspect as easy as the OH-10 is to drive, it may well be overwhelmed by too much power.


IKKO OH-1 –   of course this is the expected comparison.  The OH-10 departs from the OH-1 significantly.  While the OH-1 can be described as mildly mid-centric, the OH-10 is a bigger V shape with more detail throughout the signature.  The OH-1 is a bit more laidback, while the OH-10 is a bit more aggressive in both attack and decay and the resultant sound is a bit cleaner and sharper edged as a result.     Shells are almost exactly the same size wise but the materials used on the OH-10 make it much more solid feeling without feeling heavy or uncomfortable.

Magaosi K5 –  The mid-centric K5 vs the V shaped OH-10.  Both are built very well, cable prefrence goes to the OH-10, and choice of model is going to be dependent on prefered signature as the two have very little in common sonically.  Extension is better on the low end on the OH-10, but the K5 has better mids and arguably better treble extension.  Other than price point, these two have little in common.

Moondrop KP –  The KP is well established and liked at this price point and with both sporting polished metal shells, it again is a natural comparison.  Signatures are completely different as the eKP attempts to be more neutral than the OH-10.  The OH-10 has better low end extension as well as considerably more sub-bass than the KP brings to the table.  The KP has slightly more forward mids.  Both have lively upper mids and lower treble and both roll-off above that and are rather polite.    This is a tough call which speaks well for both models.

Brainwavz b400 –  The b400 is way closer to neutral than the OH-10, but the OH-10 is much more engaging and fun to listen to.  Build quality is night and day different as the 3d printed shell on the b400 is prone to cracking while the shell on the OH-10 looks like it could take a direct hit from a howitzer with only minimal damage.

IBasso IT-01S – These two again are similar signatures with different builds.  Both have good bass depth and an emphasized bass and upper-mid/lower treble region.  I find the OH-10 has better control at lower volumes but yields to the IT-01s at higher volumes as the OH-10 becomes slightly loose and the IT-01s comes out of its shadow.   The OH-10 sounds a bit cleaner at normal listening levels when compared to the IT-01s and has a bit better detail resolution.  The IT-01s is slightly smaller which may be a consideration for some and both are well constructed and polished although the material used on the 01s is lighter and less durable.

Thoughts / Conclusion:
Having enjoyed the signature of the OH-1, it probably comes as little surprise that I really like the OH-10.  The tonality is intoxicating and the detail and texture are very good.   It isn’t the best for those listening at above average volume, but for those that listen at average or lower volumes, it competes very well with most things in its price class.  It is not as neutral as some, but is much more engaging than most.    Even with higher end models available, I find myself reaching for the OH-10 when I just want to relax and listen.  So far Ikko has two models and two solid offerings, that’s not an easy thing to do and shows the level of effort and dedication they are putting into their products.   I can heartily recommend both the OH-1 I previously reviewed and the OH-10 as both are very solid values.  I will also admit to having IKKO’s facebook page bookmarked so I won’t miss their next release.


Pros: very engaging signature, with above average texture and detail

Cons: not a neutral signature, can get a bit loose at high volume.
Pros - Very good sub and mid bass, with good textures and natural decay
Epitome of fun yet fatigue free tuning, with strong technical foundations
Very good soundstage, with good height and depth
Superb build, fit and isolation
Very good value for money, a top notch competitor at the price
Cons - A little more lower treble energy would have made the F4 even more fun

I have purchased and paid the full retail (but nice pre-sales) price for the FIBAE 4, this is not a sponsored review.

Review notes
This review is based on over a 100 hours listening to the FIBAE 4, with various sources : AAW Capri cable for iPhone, iFi Micro DSD Black Label amp and DX220 with both AMP1 mK2 and AMP9. As usual with FIBAE IEMs, the FIBAE 4 signature is consistent across sources. My preferred combo is DX220 with the NuTubes powered AMP9. I tried several cables but PW 1960 4 wires and PlusSound X series were my favorites

The FIBAE 4 in custom form comes with a solid black plain card box which contains a black Pelican 1010 hard case with a transparent lid itself containing a small blue pouch with a cleaning tool.

  • Single low, Single full-range, single proprietary high, single proprietary super high
  • Sensitivity : 115dB @1kHz @0.1V
  • Distorsion : Low % THD
  • Impedance 8.1 Ohm @1kHz (+-0.95 Ohm 10Hz-20kHz)
  • Frequency range : 10Hz-21000Hz (+-20dB into IEC 60318-4 coupler)

2019 will be Custom Art’s year for sure, as they pushed the envelope starting with the FIBAE Black release a very singular single BA with a Helmholtz resonator which also happened to be my first Custom Art IEM. The FIBAE 4 is another release this year and innovating as well with the first to include 4 BA top firing drivers. As stated on Custom Art’s website « Top Firing Drivers provide improved frequency extension compared to traditional Balanced Armature drivers with a spout resulting in immensely detailed sound».

I loved the FIBAE Black so much (which holds a unique place in my collection with its distinctive and intoxicating tuning) that I didn’t wait for reviews and enjoyed the preorder price making it a very attractive and refreshing proposition in a soaring prices market. No brainer.

The FIBAE4 tuning was quite appealing to my tastes as well : « We tuned FIBAE 4 to be fun sounding IEM with warm and smooth signature. It offers excellent sub-bass depth and punch, detailed and natural midrange finished with extremely detailed, but never harsh highs. It combines big headroom, high resolution and expansive sound stage. FIBAE 4 is a perfect tool for guitarists, bassists and drummers for stage monitoring. »

Does it hold its promises?
Let’s see !


Fit, Build and isolation
The FIBAE Black was the first Custom Art model introducing 3D shell printing and it also was one of the best fit I ever had with customs, no matter which price point. I was very confident that the fit would be perfect and it is indeed even better than the Black in the sense that it’s just slightly less tight while retaining a perfect seal. Isolation is better than my other custom because the seal is just a little bit tighter than my other customs (VE8, Phantom and EM64 which is based on the same digital impressions). Wearing a Custom Art IEM is a fatigue free experience for sure.

The build is simply perfect, and the FIBAE4 looks sturdy to withstand every day use.

I chose a full black shell (required for 3D printing) and stuck to black plate, plain if you will. There are benefits when commutting not to attract attention, although the brand is able to provide mouth watering art on their shells, and I think when I get the FIBAE7 I’ll pick something sexier :p


The FIBAE4 is a very dynamic IEM that manages to remain absolutely smooth across the range, thanks to a softer attack and a very nuanced presentation.

It is deeply grounded in bass with very good sub bass extension with good extension and beautiful textures, providing a lot of fun and great rhythm for a toe tapping experience. Interestingly Custom Art decided to keep the mids fairly neutral with good clarity and articulation, vocals are very natural and with good presence. Treble has very good extension providing welcome air with a very natural decay, probably a benefit of the top firing drivers.

Its signature grants the FIBAE4 a very good and balanced soundstage with good height and great depth, with very good layering. The overall sense is a highly coherent fun and smooth fatigue free signature. A fun tuning for sure but a mature and refined one too.

I expected the FIBAE4 to be a fun bass experience and it is indeed but without sacrificing technicalities. Typical of modern BA bass implementation, the FIBAE4 features big BA bass driver that is able to hold its own against good dynamic drivers, especially in terms of texture and - probably a benefit of its top firing driver - a very natural decay that offers a sense of realism that few BA can brag about.

Sub bass extension provides the oh so very pleasing hit of subs. The attack is on the softer side, providing kick without being fatiguing. It boast a lot of detail and never gets saturated. It’s somewhat reminiscent of how my former 64 Audio U12 portrayed bass, only the top firing driver is at work there instead of an ADEL module and is true of the whole bass range as well.

Mid bass has good presence but it manages to stay clean and controlled something IEMs in the same kind of tuning don’t always do so well. Again, it’s a mature tuning and an audiophile take on the fun well extended subs combined with great mid bass presence. It certainly does help the soundstage depth to have a more progressive decay.

The FIBAE4 mids is where all of its seriousness is revealed, for it’s very balanced and natural. I don’t find the FIBAE4 to be that warm despite the product page claim of warm and smooth. The warmth is inherited from its mid bass rather than its mids. Mid centric tracks will reveal the FIBAE4 to be quite accurate in terms of tone and timbre, and closer to neutral with just a touch of warmth to fall into the natural category.

The lower mids are lean and clean, with enough presence to grant its mids body but not enough to color them too much. Vocal presence is really good, male vocals do shine and female vocals are just a little sweeter than pure neutral which I don’t mind at all. Textures stand out and instruments are portrayed with a lot of realism.

Last but not least - given its signature this balances things nicely -the FIBAE4 have good upper mids presence which grants a very good level articulation and separation, while remaining buttery smooth. Bass and treble are what makes the FIBAE4 stand apart but its mids stay true to the Custom Art philosophy as smooth as can be while retaining very strong fundamentals and technicality. A real treat!

Despite the prominence of its bass, the FIBAE4 treble is key to its signature and with the support of two custom BA drivers. Good treble extension is definitely a factor in both soundstage providing welcome air and good resolution and a deceptive ability to retrieve the fine details. In this sense upper treble is really the highlight point of the FIBAE4 treble wise, and while it takes a step back to the bass it plays a very defining role in the signature. Lower treble is less prominent and I wouldn’t have minded a little extra energy there, but the benefit is an absolutely non fatiguing signature.


There is no mistaking a Custom Art IEM, and the FIBAE4 is definitely not breaking the common rule : it has this smoothness and musicality that is so characteristic of the CA house sound.

It would be tempting to categorize the FIBAE4 as a U shaped signature, but I never really dug the concept of V, U or L shaped as I find them too reductive and there is much more to an IEM signature than it’s frequency range distribution. While the bass and upper treble clearly are the foundation of the FIBAE4 signature, its mids have good vocal presence and instruments are not recessed either and it’s why I think it’s a good all rounder. On top of this, the softer attack and natural decay plays a key role to the sense of realism and naturalness of the FIBAE4.

If you’re looking for a fun IEM with sound technical foundations that you can listen to for hours at times without any fatigue, then the FIBAE4 is definitely a must own in a collection especially in its price bracket! If you’re looking for fun tuning with more bite and a snappier attack then there are a few mid range IEM that could suit you more like say Earsonics Velvet v2 or - more pricey - the Earsonics Purple or Campfire’s Atlas.

Velvet Underground... Finally The Carpenters cover CD which has the Sonic Youth track i wanted for ages, and first and later Pixies and stuff