Review : Fearless Audio S6 Rui – with a Bang

Disclaimer : The Fearless Audio S6 were sent to us free of charge in exchange of an honest opinion by Linsoul. Their retail price is 399€/$ and you can find them in the Linsoul store directly.

About Fearless Audio

Founded in 2012, Fearless audio produces IEMs and CIEMs for professional users. I didn’t know the brand prior to this review, but thanks to Linsoul, I’m widening my range of knowledge every month.

If they’ve been making IEM for more than 7 years now, Fearless began to experiment with 3D-printed models in 2016 only. If that sounds early, let’s recall how far this technology has come in just a few years. Today, you – if you want – can choose your IEM to be custom-fitted (or universals), for just a fraction of what it cost a few years ago. And that’s all thanks to brands like Fearless in my opinion.

Anyway, time to dig in.

The SX Series

Unsurprisingly, Fearless offers a wide range of models to fit everybody’s tastes and budget.


The Fearless Audio Start is the entry-level IEM from the brand. It doesn’t look much different from any modern UIEM as it offers a CIEM like shape, to cover the whole ear. Once fitted in your ear, no one can possibly say you’re wearing a custom or a universal IEM.

Inside, there is 10mm dynamic driver with a Diamond Like Carbon diaphragm, something we’ve seen recently inside the iBasso IT01S in-ears. There is an option to choose which colour you want, and the cable can be swapped thanks to a 2Pin socket.


The S4 is a four balanced driver IEM with a 3-way crossover. It mixes a dual Bass Driver from Sonion with two Knowles drivers for mid-frequencies and trebles, a fairly common architecture in this range.

The IEM comes with DDP Technology and can be customized, be it custom-fitted or universal. Price is still low for this type of in-ear, so I’d be curious to see how it may sound.


S5H / S5T

The Fearless audio S5 comes in two editions. The S5H which is a five-drivers IEM “suitable for music production and stage production” whereas the S5T shows a “strong sense of low-frequency”. Basically, the S5T is a bass-boosted S5H with a prominent low end, to please the bass-lovers out there.

At the end of the day, it’s just a matter of taste.

S8 Pro / S8 Freedom

The S8 is an eight balanced driver IEM in a 4-way crossover configuration. It’s like the S4 but the brand double-downs on every driver : 2x ultra-low, 2x medium-low, 2x medium-high and 2x ultra-high.


There are two different tunings, labelled as S8Pro and S8Freedom. The first one is tuned to fit performers and music producers whereas the second one is supposed to suit musics listeners and audiophiles. Also, the impedance for the Pro version is 10 Ohms lower, at 15 Ohm instead of 25 ohms, so it should be easier to drive.

S10 Genie

The Fearless audio S10 Genie is a ten balanced driver IEM with a 4-Way Crossover. It’s not anything special now as you can more and more see IEM in the two-digit driver area. What’s surprising though, is the low asking price.

There is not much information regarding the Fearless audio S10, but the architecture is described on the website : 2x dual ultra low, 1x dual Low-mid and 2x dual Mid-high. Impedance is low at 13 ohms and the sensitivity reaches 115dB/mW, so this again should be easy to drive.


With only 8 drivers, the Acme is announced as Fearless Audio flagship, over the S10 genie. It’s not very different from the S8 Pro and S8 Freedom if you only look at the specs, but that is only half the truth.



The Fearless Audio Y2K is a very special case. First, it costs a whopping $4399USD. Second, it’s not just a 10 Balanced driver in-ear, it comes with its own amplifier. A very special amplifier. Basically, the Y2K is a tuning system that allows you to set your IEM as close as possible to what perfection is for each listener.

It’s the same kind of material you use to parameter your CIEMs/IEMs before launch, and I find it pretty cool to get a change to own this kind of setup. Just writing it, I want to get/buy one !

Now let’s take a look at the Fearless Audio S6 Rui, after all that’s what you’re here for no ?

The review continues on Page Two, 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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