Review : Fearless Audio S6 Rui – with a Bang

Design & Build Quality


Visually, the Fearless Audio S6 Rui is like any other CIEM you could get. It’s made of acrylic and thanks to how good 3D-Printing is now, the build quality is flawless. There are no bubbles and even cable management is superb when you look at it.

You can do almost anything you want it term of customization, but the standard choice is a translucent shell with the Fearless audio logo printed on the faceplate. My S6 Rui is the same as seen on Linsoul’s website : CG28 + B15 + Fearless audio Default logo.

My only drawback would be the nozzle. Without any demarcation, tips can easily get stuck in the ear canal, or get loose if you leave the units in your pocket.

Build quality

As written before, the build quality is top-notch and for 389$, you get more than you expect. It’s still not as soft as the Hidizs NF-3U, which are my reference in term of “grasp-sensation”, but it would be unfair to tackle Fearless here. To compare, it’s better than my Unique Melody Maestro and a tad under the Hidizs.

The 2-pin socket is slightly recessed to avoid pin-accident and to ensure a better grip for the cable. I’d prefer a MMCX socket as it’s sturdier in my opinion, but during my testing no issues occurred. Plug/Unplug requires just the right amount of strength. You should not lose connection on a daily basis, and when you will want to change the cable, it will be be a piece of cake.

I really like the cable they chose, it reminds me of the one bundled with the BGVP DMG. It’s almost tangle-free and thickness is never an issue. It’s a 3.5mm TRS cable, but you should have no issue if you want to switch for a balanced cable, be it 2.5mm or 4.4mm.

Bundle and Comfort

Inside the box

The Fearless Audio S6 Rui package comes in two parts. On one side, you have the basic cardboard box, which contains the tips and cleaning tools. On the other side, you have a massive aluminium case, engraved with the Fearless logo. This box holds the IEM inside, so you better check twice before putting it away.

Last but not least, you also get a very clean metal card that displays all the information regarding warranty, contact and the name of the person who built your IEM.

To sum up, you have :

  • the Fearless Audio S6 Rui
  • six pairs of colored memory foam tips + 6 pairs of silicon SpinFits
  • a 0.78mm 2-pin 8N OCC Silver Plated Cable
  • 1x plastic case + 1x aluminium case
  • the metallic warranty card

The brand doubles-down on protection and I think that’s a good thing. Even more if you’re the kind of guy who mistreats your IEMs on daily use.

Additional accessories

Like every custom manufacturer, Fearless audio gives you a large range of options to customize your S6 Rui. From the colour of the shell to the design of your faceplate, there are a lot of options available and not two customs will look the same.

The 2-Pin socket is a standard and you should not have any issue change to aftermarket cables, if you’d want to. I stuck to the default one, because I like it, very much.


With the BGVP DM6, the Fearless Audio S6 are the most comfortable ears I tried this year. The semi-custom shape fits perfectly inside my ear, it takes the whole ear up to the cymba without being intrusive. It’s a bit less aggressive than real CIEMs so if you’re not confident enough to go custom, this could be a good option.

Of course, the best option for maximum comfort would be to order them fully custom. If the earprint is correctly taken, this ensure the best isolation and fit all the time. This also means you’ll have a hard time selling them and lending them to friends and family, your choice.


The cable is slightly sensible to microphonics but it’s not a big issue in my opinion. The real issue is the nozzle which doesn’t get a stop for the tips, so half of the time you end up with the tips locked in you ear…


Isolation is good with the basic tips and even better with memory foam. The Fearless Audio S6 takes advantage of their acrylic shell to dampen unwanted sounds in all conditions. On my daily commute, it’s a good step-up from the Simgot I used earlier and on high-pitch noises it’s even better than my usual CIEM.

The review continues on Page Three, after the click HERE or by using the jump below.

4.3/5 - (21 votes)

A nerdy guy with a passion for audio and gadgets, he likes to combine his DAC and his swiss knife. Even after more than 10 years of experience, Nanotechnos still collects all gear he gets, even his first MPMAN MP3 player. He likes spreadsheets, technical specs and all this amazing(ly boring) numbers. But most of all, he loves music: electro, classical, dubstep, Debussy : the daily playlist.


  • Reply April 2, 2019

    Albert Cheng

    I am now very curious about the Y2K amp, the S10 and everything below it

  • Reply April 2, 2019

    Oleg K.

    Are Oriolus Forsteni or iBasso IT04 better than S6 Rui?

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