Oriolus Traillii
Oriolus 2020

Oriolus Traillii Review

The Oriolus Traillii is a flagship hybrid 12 driver universal IEM featuring 4 Sonion electrostatic drivers and 8 balanced armature drivers. It is priced at $5999 but for a limited time only you can avail of this discount link and use coupon code BFTrailliiJP to get a $1000 discount!

Disclaimer: The Oriolus Traillii was sent to us in exchange for our honest opinion in this review and will be returned after.  Many thanks to Musicteck & Oriolus for giving us this opportunity. 

To read more on Oriolus products we have reviewed at Headfonics you can click here.

Note, this review follows our new scoring guidelines for 2020 which you can read up on here.

Oriolus Traillii
The Oriolus Traillii is a flagship hybrid 12 driver universal IEM featuring 4 electrostatic drivers and 8 balanced armature drivers. It is priced at $5999.
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Oriolus has been in the community for quite a while. In the past few years, they have released some nice products which help them generate a great reputation in the community. Lots of fans gravitate towards their unique mid timbre and the forward, transparent vocals.

Unlike their trailblazer Oriolus/MK II/ Reborn which is budget-friendly, the Traillii is probably one of the most expensive IEMs in the market that does not have a piece of jewelry on the shells.

Well, $6000 retail is an unbelievable price that is hard to be rationally justified. However, after about 4 weeks of prudential listening, I have to admit, the Traillii is a true stunner as it should be. It is the most expensive IEM that I have ever used, and it is also the one that sits closest to the “perfect world” for my personal taste.

Oriolus Traillii


The build quality of the Traillii is good. The photopolymer shells look great and feel very silky. According to their website, the faceplate is allowed to be customized, even though the Traillii is now only available in a universal fit. Again, because I’m using the demo kit, I only have the oriental scarlet default faceplate which looks sharp and classic.

The size of the headphones is about right in the middle, not too small nor too big. Fortunately, I got a perfect fit for them. I can easily wear them for many hours without any fatigue. I have relatively thin ear tunnels, so do prepare larger ear tips if you have big ears.

Packaging & Accessories

The unit I have is a testing demo, I hope the actual product has more accessories and probably a more luxurious-looking package. The demo kit per se somehow reminds me of L&P P6 which has been reviewed on Headfonics a few weeks ago.

The package and accessories of the Traillii are simple and practical. A few pairs of nice quality tips and a carrying case in good size and quality, that’s it. If I don’t know the price, it would be fine for me, but ahh… I think at the summit price range, the package should be on par with Erlkonig or at least it should be as unique as Thummim.

The good thing is the Traillii comes with a specially tuned cable that is based on PW 1960s 4 wires. Compared with the original 1960s 4 wires, this cable sounds slightly leaner with better bass and lower mid texture.

I found this specially tuned cable sounds perfect with the Traillii, I switched some other premium cables, including the original 1960s 4 wires. I didn’t find another cable that fit particularly better than this specially tuned 1960s.

Oriolus Traillii

Sound Impressions


Ultimately sound is the only thing that matters. At $6000, I presume customers would expect something special. A very long-time debate in the community is how and when would a pair of IEMs be comparable to full-size headphones in terms of sound quality.

Personally, I’m rocking both full-size headphones like Abyss, Sennheiser, Focal, and Hifiman as well as portable systems. I found most of the IEMs today are still lacking good bass texture, scaled 3-dimensional soundstage, image accuracy, and dynamic compared to full-size headphones.

The Traillii is the first pair of IEMs that makes me feel like listening to big cans in almost all aspects. Despite the price of the Traillii skyrocketed, I do feel it is an IEM on another level. Especially in staging and imaging. That makes me feel that it is well worth it at least for a moment.


The Traillii is a balanced but not a flat sounding IEM. It has a very neutral timbre with a touch of musical warmth in the mid-range which I categorize as the house signature of Oriolus.

If you have ever experienced their products you will understand what I am saying. It has a great definition of bass, mid, and treble without being cold and colorless. The four latest provides some nice sparkle without being overly bright.

As a matter of fact, the Traillii is not even a bright IEM. I found the timbre of the Traillii is very lively and accurate, with a soft and rounded edge in the ultra-high frequency.

The tonality is also in a world-class balance without leaning towards a certain frequency range. It has a very natural, coherent sound and the transition is gapless and silky smooth from the bottom to the top. To my ear, the Traillii sounds more like a planar headphone rather than a multi-BA or an electrostatic hybrid IEM.


The soundstage and imaging from the Traillii are word-class. I would never dream of this type of presentation from a pair of IEMs. The soundstage from the Traillii is large, holographic but not hollow and boundaryless.

You will easily find many sounds and details that are placed out of your head, but the images maintain a good definition. All the vocals and instruments sound clear and realistic within controllable distances.

The Traillii finds the sweet spot between the size of the stage and the accuracy of the image. Every note from the Traillii sounds free and smooth breathing.

Thus, it sounds more natural than almost any other IEM that I have ever heard. On the other side, the soundstage is not overly sized up and lacks an entity or focus. Without a doubt, the Traillii has the most organic soundstage that I can think of as an IEM.

Oriolus Traillii


The Traillii uses four BA drivers for the bass region. However, the bass sounds full and has great decay, which is nowhere like the traditional BA bass we have heard. It is again more like “planar bass” which is not as fat and punchy as “dynamic bass”.

The bass from the Traillii maintains great speed and clear of any unwanted grain. Maybe, it is not the IEMs that have the greatest bass impact like Thummim that I have reviewed recently, the bass impact is still very satisfying.

For classic symphonies, the Traillii’s bass is a little lean and on the gentle side. For string instruments, this type of bass works great, but for wind instruments and percussion, the bass is a little less impactful.

For modern genres, the Traillii’s bass is ideal! I have tested many funk, rock, metal, and EDM tracks. The Traillii’s bass sounds very lively and energetic. Perhaps, it is the fastest bass I have heard recently. The bass hits hard and deep, and it sounds very focused.

Meanwhile, the bass details and resolution are also on the top of my list. When I listen to bass solos from Victor Wooten, I find the bass slaps and walking flows are illustrated clearly right in front of me. Air slapping, body shaking, headbanging!


Oriolus has a very unique tonality in the mid-range. The Traillii succeeded in this house signature with an elevated mid-range performance and an even more artistic tuning.

The Traillii’s lower mid is very full and meaty. For male vocals, the Traillii sounds lush and full of emotion. The Traillii also adds a little creamy nature in the lower mid too, which makes the notes sound more fluid and enjoyable.

The upper-mid is where the Traillii’s mid stands out and differentiates from our compared competitors. For most multi-BA and electrostatic hybrid (tribrid with dynamic driver) IEMs, there is a compression in the upper-mid around 4k-6k.

As a drummer, I am very sensitive to these snare and cymbal compressions. However, it is not the case for the Traillii. It is upper-mid is forward, with a clear presence and resonances. But it is not very aggressive. The Traillii successfully cuts the unwilling edges at this frequency range like there is a sugar coat covering the popping body of the upper mid.

The mids clarity is superb where I can easily detect the voice vibrations, small motions, and breaths of the singer almost physically. Interestingly enough, the presentation of these details are not crystal transparent. It is like the tree behind the mirage where you can see but you can never touch it.


I do enjoy the treble from the Traillii a lot! It is equipped with 4 of the newest Sonion electrostatic drivers which offer fantastic treble extension and yet are very smooth and refined. The trumpet and woodwind sound tight and elegant. It has a great treble density which makes the instruments sound very realistic and vivid.

As a natural-sounding IEMs, the Traillii’s treble is not very bright but not dark as well. You will get enough sparkles, but if you are looking for a crispy, glassy treble, the Traillii is not what you should look for.

The Traillii focuses more on the overall coherence which doesn’t let one single range stand out and interrupt the completeness. If you are looking for a natural, realistic, and refined elegant treble the Traillii might be your choice.

The technical performance of the Traillii is excellentt. Great micro-dynamic, top-tier clarity, and resolution you will have all these good things from the Traillii. It is something that is hard to make people tired of.

Oriolus Traillii



The Traillii is rated at 21Ω and 112dB SPL. It is quite easy to drive as a BA and fairly sensitive for an Estat hybrid IEM. With the Hiby R8, I can detect some background noises, especially when turning the HiBy R8 to the Turbo mode which most IEMs would have a similar humming issue.

So, I personally would not rate it as a noise detector, it is still at a normal noise level and nowhere close to Campfire Audio’s more sensitive IEMs.


I tested the Traillii on an AK SP1000M, Hiby R8, and a Cayin N6ii A01. Good news is that the Traillii is not a peaky source pairing. With different DAPs, the Traillii will offer you different enjoyable flavors. However, I think it largely benefits the most from a natural and versatile sound signature.

With the SP1000M, I got a lithe and lively presentation. The upper frequency is slightly thinner and crispier than with the other 2 DAPs. With the Hiby R8, the soundstage is further extended, the mid and vocals are less vivid compared to SP1000M, but it still has some sweet voicing.

The Cayin N6ii delivers the least transparent sound, however, this combo sounds fuller, warmer, and more engaging. I do like the Traillii with the N6ii for most classic rock music.

Vision Ears Erlkonig

Select Comparisons

VE Erlkonig

(Switch to Mode 2, Neutral, €4299)


The Traillii and Erlkonig are two of the most exotic IEMs I have heard. Both have some great build quality but the silver shells of Erlkonig add more of a premium feel. However, the Traillii is lighter and more comfortable for me.

Both manufacturers offer customized faceplates. Oriolus offers more choices in terms of color and inner materials. VE offers changeable faceplates and you can always DIY with additional purchase on faceplates.

Beyond the appearance, Erlkonig allows customers to choose between 4 different sound signatures by turning the switch system underneath the changeable faceplates. The Traillii is not equipped with such a system, you got one finalized tuning with the PW cable.

Erlkonig is rated at 16Ω and 105db SPL or sensitivity. Both the Traillii and Erlkonig are relatively easy to drive and “cellphone friendly”. I can rock both of them with my Samsung S10 with enough volume and both of them do not sound weak or tempered.


Both IEMs have a completely different tuning ideology. Erlkonig focuses more on sound density sounding more full-bodied and with significant macro-dynamic focus. The Traillii focuses more on stage, image, and overall coherence.

Erlkonig’s bass is closer to the “dynamic bass” which sounds fuller and more intense. The Traillii’s bass is more relaxed and natural with a touch more decay. Both of them have great bass clarity, but I found the Traillii’s bass reaches a touch deeper. 

Erlkonig has a more forward midrange, with a larger imaging size. It is also slightly warmer. The Traillii is more neutral and realistic in terms of mid timbre. Erlkonig put the singer closer to the audience, but that is not saying the Traillii sounds distant. You could say it is more relaxed and objective versus Erlkonig’s involving and fun tuning.

Erlkonig’s treble is very engaging and attacking. It is not sharp but compared to the Traillii it is closer to the “in your face” sound. It has a more ‘brilliant’ signature whereas the Traillii is smoother and more placid. The difference is more noticeable when playing high tempo music.

As I said earlier, the Traillii stands out as a master in soundstage and image. Erlkonig’s sound stage is OK but relatively narrower compared to the Traillii and some other competitors. I found the Erlkonig is a little stretched when playing classical symphonies, but that is never an issue for the Oriolus.

MMR Thummim

MMR Thummim



The Thummim has the most unique shell design and one of the best build qualities. However, the Traillii still fits better to my ears.

Both IEMs offer high-end cables from top cable manufacturers. The Thummim is equipped with Eletech 24AWG Plato silver cable and the Traillii comes with the specially tuning all-time classic, the PW 1960s 4 wires.

The MMR Thummim is rated at 35Ω with an unrated SPL officially. In reality, I found the Thummim is noticeably harder to drive. Even with AK SP1000m, Thummim sounds clustered or compressed. I feel the Thummim would need at least 700mW to 1W output to fully reveal its potential. I have even tested them on desktop amplifiers and Thummim doesn’t seem to be overfed.


The Thummim is more bass oriented. It has significantly more bass quantity and weight. Thummim is a canonical V-shaped IEM whereas the Traillii sounds more balanced and neutral. It is a classic reference tuning IEM. I can see enthusiasts enjoy both of them but the signature between these two IEMs are quite polarized.


The bass is the most prominent frequency of the Thummim. The 9.7 mm Foster dynamic driver provides tons of bass quantity and energy. The sub-bass fills the entire room when you plug them in your ears.

Besides the quantity, the bass quality of the Thummim is also stunning with a nice texture, a great amount of decay, and a very focused bass attack.

The Traillii’s bass is more neutral in terms of quantity. It hit faster but lighter compared to the Thummim. Unlike the Thummim, the bass of the Traillii is well controlled and will not bleed into mids.

MMR Thummim


The mid of the Thummim is slightly recessed compared to the Traillii. The Traillii’s mid has better resolution and the sounds are placed closer to the audience.

I get more precise details from the Traillii and also it connects bass and treble in a much more smooth and natural way. The Thummim sounds a bit muddier and is less accurate to the music and with more artificial warmth.


Both the IEMs offer great treble extension but again the Traillii sounds the more natural and the Thummim sounds more fun and edgier.

The Thummim has a unique goldish aura surround the peak notes which makes the Thummim the most engaging treble among these three TOTL IEMs. The Traillii offers the ultimate comfort in the treble frequency, it is smooth, refined, and inoffensive. I do enjoy both of these IEM’s treble for different genres and in different modes.

Both IEMs have the largest soundstage in my IEM collection. The Thummim is slightly wider, but the Oriolus is slightly deeper and has a more “out of head” effect.

The Thummim has a larger image size with both vocals and instruments offering a big and expanded presentation. The Traillii is more loyal to the music, the images are smaller and more precise, each note has a larger “personal” space in its presentation.

Our Verdict

The Traillii is the most natural-sounding IEM I have ever heard in my life so far. Before this review, I don’t have a “personal favorite” IEM. Sometimes I prefer one pair and sometimes I like another more.

However, the Traillii is the killer here, it really shocks me for a long while, and soon becomes my favorite IEM. It is like a high-end full-size headphone that can be driven by my cell phone or DAP. I can bring this IEM to anywhere I want and get a similar sound quality to what is on offer when using my desktop system. Just think about it, it is crazy.

Oriolus Traillii Specifications

  • Body Material: Photopolymer
  • Transducer Type (per CH): Electrostatic Driver*4; BA Driver*8
  • Sensitivity: 112dB/mW
  • Freq. Response: 20Hz40kHz
  • Impedance: 21Ω
  • Cord: Pure Audio Grade Copper (PWaudio)
  • Plug Type: 4.4mm Balanced


  • Silicone Eartips (S M L 2-flange-M)
  • Foam Eartips (S, M)
  • Protect Case (Van Nuys)
  • Round Twintube (Van Nuys)

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