Oriolus Traillii

Small IEM with a BIG Sound!

PROS: hybrid (8BA/4EST) design with a natural full body detailed tonality, powerful bass impact, and a balanced sound sig, 3D holographic soundstage, durable compact shells, premium PWA cable, VanNuys carry case.

CONS: price, universal fit only, nothing to nitpick unless you prefer a different sound sig.

The product was provided to me on a short loan from MusicTeck for the review purpose in exchange for my honest opinion.

Manufacturer website: Oriolus Japan.  Available for sale from MusicTeck.

For a limited time, MusicTeck is running a Sale promotion with $1000 off the price of Traillii when you use BFTrailliiJP code at checkout.


The only time I use preamble in my reviews is when I talk about cables because I find that discussion to be a rather controversial topic which needs some additional explanation before the Intro.  So why would I start IEM review with a preamble?  Because I need to address the elephant in the room, the price tag of Oriolus Traillii which is $6k.  When I heard how much it cost, a thought ran through my mind that we crossed yet another price threshold and now entering a new chapter of premium IEMs.  But is this really a new chapter?

Every time I review flagship IEMs, I get asked about different premium cable pair ups.  And some of my readers are well aware of Nic’s thread on Head-fi where I see a lot of discussions from head-fiers who use their kilobuck IEMs with high end cables.  The price of Traillii is not for everybody, but there is a number of audiophiles who already own $5k-$6k IEM/cable combos because they want to squeeze out every ounce of performance, don’t mind diminishing returns, and still find it cheaper than 2 channel home systems where a power cable alone can cost as much.


So, let’s put down pitchforks and torches, and if you are still curious about this new IEM release from Oriolus with a premium PWA cable, proceed further to read my review of Oriolus Traillii latest hybrid flagship.


Actually, this review feels a bit like a déjà vu from 2018 when I visited Oriolus/Hyla table at CanJam NYC and heard Oriolus Mellianus for the first time.  I couldn’t get its tuning out of my head and just had to review it.  Now, 3 years later, I continue to use and to feature Mellianus in a number of my reviews as part of comparison and cable pair ups.  Fast forward to 2020, and I saw the announcement from MusicTeck about a new Oriolus Traillii flagship which of course caught my attention even before I read the price.

My original plan was just to hear them without a commitment to review, and I was happy for the opportunity to spend a few days with Traillii.  While I’m trying not to use the word “spoiled”, I do feel a bit jaded after having a chance to hear and to review so many different flagship IEMs, to the point where it is hard to get excited about another one.  And as usual, I didn’t know what to expect, but after putting these in my ears, I immediately asked MusicTeck if I can hold on to them for a few extra days so I can write full review.

Another interesting thing was Traillii being released under Oriolus and not Hyla name.  For those who are not familiar, Oriolus was formed in 2015 under the umbrella of Cyras Co. in Japan, and had a number of successful IEMs, DAP, DAC, and Amp releases.  In 2017, Cyras added a more upscale line of IEMs under Hyla name, though this latest premium flagship release ended up under Oriolus name.  But regardless of the name, what really counts here is how this little bird sings, so let’s proceed to find out more.

Unboxing and Accessories.

Arrived in a smaller size plain carboard box, inside you will find a custom VanNuys storage carry case which is pretty much the whole packaging of the product.  VanNuys (Japan) are well known in audiophile world and usually hard to find outside of Japan.  This ballistic nylon multifunctional case with Oriolus name on the cover has a padded poly mesh inner lining and adjustable velcro partition to make a separate pocket for storage of other accessories like eartips.  Plus, it comes with a twin-tube double sleeve (in red) to separate earpieces so you can keep them apart and secure during transportation.  Though I do like VanNuys storage case, it is not exactly pocket friendly.

Other included accessories are a set of S/M/L regular wide bore silicone eartips, a set of M size double-flange eartips, and a set of S/M foam eartips.  You will also find a cleaning tool, and a removable cable shirt clip, though the spring-loaded mechanism to attach to the cable won’t work with the included thick PWA cable.  I assume this cable clip is a standard stock accessory for use with thinner cables.

Overall, the packaging and accessories are practical, but at this price the unboxing lacks a wow-factor.


The stock cable is a customized version of a popular PWA (Peter Wong Audio) 1960 4-wire (8conductors) cable which retails for over $2.2k by itself.  As I mentioned in my EE Odin review where they also used PWA 1960, these cables are quite popular and in demand even considering their premium price.

The cable uses 26AWG gauge wires and FEP jacket for a positive signal (as part of the core) and 24AWG gauge thicker wires and PVC jacket for a negative signal (as part of the shielding).  The wires are insulated and combined under a tightly braided black carbon fiber sleeving which has a nice touch and still feels very flexible.  Don’t expect a see-through jacket which showcases the wire.  This cable is not about pretty looks but performance and isolation, using UPOCC Litz Copper premium wires presumably sourced from Cardas.

Since positive and negative signal wires are combined under the same sleeve inside of a coax cable design, you can only see two Left and two Right wires, thus a name of 4-wire cable, but you have a total of 8 separate conductors, 4 on each side.  The cable comes with a brand name genuine Pentaconn 4.4mm plug, carbon fiber black y-split, and PWA signature wooden round chin slider designed to minimize microphonics effect.  Toward the connectors you have a flexible clear heat-shrink earhook going into PWA 2pin connectors with red/black ring marking and red/black short strain relief to indicate Right/Left sides.


Before I go into the design details, I want to point something out.  Often, people make assumptions that a flagship IEM should have a fancy look.  If you Google “Traillii” you will see that it is a type of a small flycatcher bird that looks rather plain from outside, until it starts to sing.  As Wikipedia says “… their song is the only reliable method to tell them apart in the field” from other similar birds.  That pretty much describes how I felt about Traillii when I put these small shells in my ears and let them sing!  Don’t know if this is what Oriolus guys had in mind, but it sure does make sense to me.  While Traillii doesn’t look as flashy, once you hit Play you will hear a BIG sound.

The IEM itself has a 12driver design with a 3-way crossover that partitions drivers into 2BAs for lows, 6BAs for mids, and 4ESTs for highs.  And despite 8BAs and quad ESTs along with voltage transformers, everything is squeezed inside of a very compact clear shell with a unique brownish/reddish faceplate finish covered in hairlines of fiber strands.  Oriolus also offers a selection of 36 alternative custom faceplates, but they do have a warning it will delay availability of Traillii if you decide to customize it.


What is interesting, despite packing a more advanced hybrid design config inside, Traillii shells are nearly the same, and maybe even a touch smaller than all-BA Mellianus.  The body of the shell is made using Photopolymer material, and as I already mentioned, the shell design is very compact with a transparent body and standard universal faceplate selection which can be customized.  The nozzle is a bit thick and shorter, has a secure lip at the top, and has one large bore opening and 3 smaller ones.  Also, 2pin socket is recessed, just like in Mellianus.

The fit was very comfortable and secure with stock eartips, and with shells being so lightweight I didn’t even feel them in my ears.  I do know that some people prefer CIEMs, but I’m not aware if one is available for Traillii.

The fit.


Page 2 – Sound analysis and Eartips selection.
Page 3 – Comparison, Source pair up, and Conclusion.

5 thoughts on “Oriolus Traillii

    1. It’s hard to compare to one IEM, Bobby. In general, Trailli is what Thummim should have been, combined with likes of Elysium, Odin, and A18s. Keep in mind, I spent less than a week with Trailli and haven’t heard Erl yet, but it strikes me as the signature where I can’t think of changing anything. Of course, we will be kidding ourselves by calling any IEM “the endgame”, but this one is special for sure.


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