The comparison between two of the heavy weight bass-canon IEMs for the moment (or forever?) the FatFreq Scarlet Mini Universals vs. the hype-worthy TSMR (Tansio Mirai) Shock featuring the patented revolutionary Sonion Bone Conduction technology. According to TSMR description: " The double L-shaped membrane channel allows the sound of the bone conduction driver to be conducted through the ear cartilage, greatly improving the application efficiency of the bone conduction driver inside the in-ear monitor. The bone conduction driver has stronger penetration, and the many subtle vibrations generated can be felt by the body. The way the cartilage contacts can also allow the ear to receive more comprehensive sound information as a whole, enriching the layers and making the sound more holographic and three-dimensional, further enhancing the spatial sense of the in-ear monitors."
Four balanced armatures work in unison to create a holographic, three-dimensional soundstage with exceptional tactile feedback - everything electronic music lovers crave in their IEMs.
The Scarlet Mini brings its own advantages with claims of the worldās first and only 30dB sub-bass shelf with outstanding low-frequency control below 200Hz. FatFreqās proprietary tubeless hyper-tweeter system delivers cosmic high-frequency extension and crystal clarity up to 40kHz.
Sound signatures differ significantly: the Fatfreq Scarlet Mini offers an L-shaped response (emphasized bass, relaxed highs), while the TSMR Shock delivers a V-shaped signature. Both are allegedly āmid-tierā priced - yeah right, at $600+ theyāre stretching that definitionā¦ For brevity, weāll refer to them as Scarlet and Shock respectively.
Test Setup:
Hardware: Hiby RS6 DAC
Software: USB Audio Player in Bit Perfect mode
Sound enhancements: Only Ultra Darwin (applied globally)
Test track: Shitstorm by Vandenberg
With an impedance of ~16Ī© and sensitivity of ~108dB/mW, the Shock is driven easily by most smartphones, though they truly shine with more powerful sources. The Scarlet shares similar specs, though itās 3dB less sensitive. To achieve equal volume, I needed 44 volume steps on the Scarlet versus 34 on the Shock - that 10-step difference is significant for portable use. This translates to some battery savings, but weāll discuss that in the Conclusion part.
The Shock contains one dynamic driver, two BAs, and one Sonion BCD (Bone Conduction Driver) per channel. It also features a frequency switch system allowing precise separate adjustment of highs and lows. This is both a blessing and a curse - while it enables extensive sound customization, achieving perfect channel matching can be challenging. You can radically alter the tonality with these adjustments. Iāll include a link to my squig.link page showing frequency response measurements of the compared IEMs as well as Shockās tuning results - though these naturally represent extreme settings, as comprehensive measurements could literally take a year.
Thereās another interesting opinion that Sonionās bone conduction drivers deliver remarkably capable bass in default settings, but when adjusted toward a more bass-heavy tuning, you can truly appreciate their full potential. Rumors even claim these are the same BCDs used in the $4,000 Penon $3.600 flagship Monitor Rival.
The Scarlet employs a simpler 1DD + 2BA configuration. Both IEMs share an identical 5Hz-40kHz frequency range, promising earth-shaking sub-bass and sparkling ultra-highs with diamond-like brilliance. According to manufacturer specs, the Shock delivers a similar performance.
FatFreq Scarlet Mini Universals
If youāre unfamiliar with FatFreq, just glance at their Meastro Range frequency response graph and you will get a general idea about those IEMs.
While these IEMs deliver competent but unremarkable bass on non-EDM genres, the moment you play electronic music (house, techno, drum and bass, etc.), they teleport you to another dimension. The connection to the outside world vanishes as youāre engulfed in a hypnotic dancefloor vortex. Kick drums physically penetrate your chest, basslines rewire your psyche, and the addictive pressure makes removal of Scarlet unthinkable. These crimson marvels achieve the impossible and no other IEMs on the market come close.
General Performance
Genres: Excels at everything except distortion-heavy metal (though bass never bleeds into other frequencies).
Separation: Not perfect, but zero muddiness even in complex passages.
Eartips: Community claims tip-sensitive, but for me stock L tips were perfect for me.
Iāve owned Scarlet Mini since early 2024, and they still astonish me. But thereās a real problem. All other headphones sound like tinny toys with EDM music played. That is why I try not to listen to Scarlet every day as theyāre home-only treasures and I have tons of other IEMs which I listen out-of-doors.
TSMR Shock
Bass
Tight, textured, and punchy but mid-bass dominant vs. Scarletās sub-bass which rumbles like nothing else. To me the Shock is a better option for outdoor use.
Mids
Balanced V-shape with BA-enhanced clarity.
Vocals: Natural and rich (male vocals especially), zero harshness.
Switches: Mids feel recessed at all settings except ā0-0ā (both dials neutral).
Treble
Scarlet: Unobtrusive yet sparkly, ādewdrops on an early July morningā-ish
Shock: Brighter with a BA-esque zing
The FatFreq Scarlet Mini Universals are engineered for bass purists - delivering subwoofer-grade low-end reproduction with zero treble harshness. These represent the ultimate, irreplaceable headphones for the 80%+ hardcore bass-heads, particularly EDM devotees who demand tectonic sub-bass impact.
TSMR Shock caters to hip-hop fans and lovers of fun, energetic V-shaped sound signatures. Its crown jewel is technicality: best-in-class detail retrieval, a wide soundstage with pinpoint instrument positioning, exceptional separation, and remarkable āairinessā. The immersion factor operates at an elite level.
Both IEMs are my personal Endgame: Shock is for out-of-doors (mid-bass cuts through the outside noise). Scarlet is for home (sub-bass sovereignty).
I have no doubt whatsoever this duo will satisfy my bass needs for 3+ years, though Iāll still keep an eagle eye on new releases (old habits die hard).