Fearless Audio S6RUI

Sound Analysis.


If you like bass and have been complaining that balanced armatures can’t play bass all this while, THIS IS YOUR IEM! The S6RUI has good-punchy-impactful bass that I’ve always expected from a dynamic driver. I like it! It has good rumble when required, the sub-bass can go low, mid bass and high bass shines in songs with overdriven bass playing in bands like Karnivool, Muse and the likes.

Let’s dig-in in detail with some songs as reference.

  • Kanivool’s Simple Boy & Goliath – If you’ve been reading my reviews, you know I love these two songs for the bass. The S6RUI nails the overdriven bass sound. It has well present sub-bass, good mid-bass and snappy high bass with good bass string definition.
  • Chainsmokers’ Somebody – If you’ve heard and like this song, I’m sure you would’ve gotten hooked to its falsetto based hook line. But right after the intro, an 808 and an overdriven stereo synth bass makeup most of the instrumentation.
    Both the basses have good impact and separation, keeping their individual identity strong and present throughout the track.
  • Muse’ Panic Station – It starts with a bass slide and off to a snappy groove where the S6RUI makes the bass shine along with the drums. In most BA sets, the drums take the spotlight. But the S6RUI re-creates the gnarly bass tone that Muse is known for with utmost ease and poise.


The mids have good weight to them. They sound natural, thick while still very smooth with great clarity and separation. I know these adjectives don’t generally go together but well, it is true in the case of S6RUI. The lower mids enable the snares to have good body and meat whereas the high mids help guitars with attack and percussion shells with good stick attack. Instruments have a good timbre and vocals sound authentic and life-like, as if the artist is performing right in front and only for you.

  • Ed Sheeran’s Thinking out loud – Ed’s voice sounds very natural. The strat guitar tone sounds very authentic too. The separation is so good that I can even hear the spring reverb every time he percussively mutes the strings while playing the main chord progression.
  • James Bay’s Hold back the river – The hollow body Epiphone that James uses sounds so natural that I can certainly hear its authenticity. James jumps between his real voice, head voice and falsettos dynamically throughout the song. His vocals are presented very well by S6RUI. All the voices in the falsetto based chorus are identifiable individually. The tambourine also sounds very natural and well present whenever it is played in the song.


The treble is smooth. It isn’t overly boosted which helps give S6RUI a smooth character and also keeps it fatigue free. But don’t mistake it for being a dark sounding set. Even though the treble is smooth, it still extends decently well and enables S6RUI to have good clarity and definition. Also, there are no rogue 8kHz peaks so you’re not going to hear any added sibilance here.

Soundstage, Imaging and Separation. 

Soundstage has more than average width, I’d rate the width around 7 out of 10 (where 5 is average). Imaging is precise and well done. Separation, layering and resolution are very good for the price. I guess the drivers are doing their job, playing their parts well.

fearless_s6rui-S6RUI 1

S6RUI vs S8 Freedom

As everyone is extremely interested in this comparison, I hope I can do it justice.Think of S6RUI as S8F’s sibling who is younger by a year (2 drivers). S8F sounds more airy and creates a better sense of space. It has more sparkle and snap in the 2-6kHz region. The mids are thinner and have better resolution. The bass sounds more authentic, tight and cleaner but both S8F and S6RUI have good slam! Personally, for me the S8F sounds more exciting and refined, with better resolution overall.

But on the other hand, S6RUI is warmer of the two and an easier listen. If you don’t want as much resolution and prefer listening to an easier sound signature, go for the S6RUI. But if you want a more detailed and resolving IEM, S8F is the one.

fearless_s6rui-S6RUI 5 with cable


S6RUI is a very impressive IEM from Fearless, who have priced it extremely aggressively. It is one of the cheapest 6 BA driver IEMs which uses all original Knowles and Sonion drivers. It has very good build quality, countless faceplate and customization options but the MVP of this unit is its extremely well-tuned and enjoyable sound signature. If you want a jack of all trades, this is the one to get. Highly recommended!

Gear used for testing and review.

  • Logic Pro X session with hi-res test tracks played through Universal Audio Apollo or Focusrite Clarett Pre X audio interface headphone out.
  • Hiby R6 Pro
  • Oneplus 7 Pro

Reference Songs list.

  • Foo Fighters- The Pretender, Best of you & Everlong
  • Coldplay- Paradise, Up in flames & Everglow
  • Ed Sheeran- Thinking out loud, Bloodstream & Galway Girl
  • Chainsmokers – Somebody, Sickboy, This Feeling & Closer
  • John Mayer- Slow dancing in a burning room, Stop this Train & Say
  • Gavin James- Always & Hearts on fire
  • Switchfoot- Meant to live & Dare you to move
  • Linkin Park- Papercut, Somewhere I belong & Talking to myself
  • Maroon 5- She will be loved, Payphone & Lost stars
  • Lifehouse- All in all & Come back down
  • Karnivool- Simple boy & Goliath
  • Dead Letter Circus- Real you
  • I Am Giant- Purple heart, City limits & Transmission
  • Muse – Panic station
  • James Bay – Hold back the river

2 thoughts on “Fearless Audio S6RUI

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