This is a full written review of the new Softears RSV-MKII – the 2025 revision of the original “Reference Sound” RSV from 2021. The previous generation is one of my all-time favorite IEMs and I have used it nearly daily since my full review that you can read up on here. I have already highlighted the new features of the revision in this introduction and also shared a comparison with the original RSV on Head-Fi.

Introduction

The official product name is the Softears RSV-MKII (derived from the Chinese 二代, meaning “2nd Generation”), though you may also see it spelled as MK2, Gen2, V2, or simply II. It’s worth noting that Softears’ own naming conventions can be inconsistent; the original model was sometimes referenced as the RS5.

Given its placement in the “Reference Sound” (RS) line – which debuted with the exceptionally neutral RS10 flagship which I reviewed here – one might expect a studio-flat monitoring signature akin to the first RSV. However, the second generation follows a different philosophy. It is a more coloured and engaging listen, positioning itself as a premium all-purpose IEM rather than a strict analytical tool. This invites a reinterpretation of the “Reference Sound” name: perhaps it now signifies a reference-grade, subjectively excellent sound at its price point, rather than absolute neutrality.

The Softears RSV-MKII is currently priced at approximately 4,399 RMB or $699 USD.

Technical Information

The RSV-MKII is an all-balanced armature design employing a 4-way crossover. It is highly efficient, rated at 122 dB/Vrms, with a very low impedance of 7Ω. This high sensitivity means it could potentially reveal background hiss on noisy sources, though all sources I tested – including the iBasso DX260, Questyle M15i, a custom CX31993+MAX97220 dongle, and a Retroid Pocket Mini V2 – remained silent.

The low impedance is a more critical factor, as it can make the IEM’s tonality susceptible to change based on a source’s output impedance (OI). On the original RSV, a higher OI resulted in a reduced bass response. While I cannot yet confirm this effect on the MKII with measurements at this moment, it remains a consideration for potential owners.

The driver configuration is as follows:

  • Bass: Two Knowles CI-22955 balanced armatures, known for their strong output and long-excursion diaphragms.
  • Mids: A modified ED-type balanced armature, optimized for a natural and cohesive midrange response that captures vocal nuances.
  • Highs: Composite double SWFK-type balanced armatures for treble reproduction.
  • Passive Radiator: A sixth, passive BA acts as an air damping mechanism, managing internal pressure and enhancing bass response.

Build Quality

The shell is crafted from filled, 3D-printed medical-grade resin, offering a warm, comfortable feel and a deep black colour. The faceplate is CNC-machined aluminum, anodized with a matte finish and reflective “RS” lettering. A large ‘V’ (the Roman numeral for five) is inlaid with randomly arranged carbon splitters sealed under resin – a subtle nod to the original RSV’s carbon-and-gold-flake design, though the connection may be lost on new users.

The nozzles extend fully to the tip, with no protective mesh; users should clean their ear tips regularly. The nozzle itself is slimmer than the previous model and features an effective lip to secure ear tips. While the housing shape is unchanged, the updated nozzle and the addition of a pressure-release vent significantly enhance comfort by eliminating the ear fatigue associated with fully sealed designs. The passive radiator further aids in pressure management. For my medium-sized ears, the MKII is among the most comfortable IEMs I own.

Accessories

Cable

Softears includes an excellent stock cable, continuing a welcome industry trend that reduces the immediate need for an upgrade. This all-black cable, branded with ‘RS’ lettering, features 228 strands of deep-frozen high-purity copper, braided with a ‘counter-twist’ method to minimize inductive effects. It offers great thickness, minimal memory, surprisingly low microphonics, and a slightly glossy jacket material.

My sole critique lies with its 4.4mm termination. Given the IEM’s high sensitivity, volume requirements are very low, often under 10% on most sources, which can limit the usable dynamic range of an amplifier. A 3.5mm termination would have offered broader compatibility with consumer devices like game consoles and older portables. While the included 4.4mm-to-3.5mm adapter solves this, a native single-ended option would have been more practical. That said, this is a superb cable that also pairs beautifully (sonically and visually) with the Softears Enigma (featured here).

Ear Tips

Two sets of silicone ear tips are included: a ‘B’ (Balanced) set and a ‘UC’ (likely Ultra Clear) set made from liquid silicone. Both come in three sizes (S/M/L). The ‘B’ tips were used during the MKII’s tuning, but the ‘UC’ tips generally provide superior comfort and seal for me. The ‘B’ tips sit deeper in the ear canal, resulting in a slightly more forward treble presentation.

No foam tips are included. For those who prefer them, third-party options or DIY solutions (which work excellently with this model too) are recommended. An optional upgrade, the very expensive Softears UT tips with titanium tubes, is sold separately for improved sonic stability. I bought a set but size M was too small on this particular IEM so I can’t say how it pairs.

Carry Case

The included round faux-leather zippered case offers average protection. It’s functional, but most enthusiasts will likely have a preferred alternative already. Personally, I use the Peak Design Tech Pouch S for my daily commute (featured here).

Sound

Tuning

The RSV-MKII represents a philosophical shift for the Reference Sound line. Where the original RSV and RS10 pursued measured neutrality, the MKII prioritizes natural timbre and listener engagement. Its signature is best described as slightly bassy and warm, with significant weight and impact. The midrange remains largely neutral and excellent, while the treble has been shifted, softening the lower treble for reduced fatigue and adding a touch more upper treble.

This is a bold, more consumer-friendly tuning that closes the gap to the popular Volume S. Whether it constitutes a “better” reference is a matter of perspective and priority.

Bass

The twin Knowles bass drivers deliver impressive authority, impact, and heft. The tuning is excellent, offering a homogeneous balance of rumble, punch, and texture without favouring any single aspect. There is minimal midrange bleed, though the elevated quantity means thump and power are immediately apparent before finer textural details become clear. Personally, I would prefer 3-5 dB less emphasis, but this is a subjective preference many will not share.

Midrange

The midrange itself is essentially untouched and remains a benchmark in its price class. However, the changes in bass and treble affect its presentation. The added low-end weight grants instruments and vocals a more grounded, physical presence, making them sound more lifelike and three-dimensional. The softened lower treble takes the edge off sibilance, creating a more natural, less “hi-fi” reproduction. If you admired the original RSV’s midrange, you will find the same core quality here, now framed within a richer, more forgiving presentation.

Treble

The lower treble has been deliberately softened – an interesting choice given the original’s acclaimed transparency. This trade-off eliminates harshness and enhances musicality, but it also distances the MKII from a strict “reference” monitoring tool. Tracks known for sibilance are rendered smoothly, which may not translate accurately to more neutral playback systems.

As a benefit, attention is shifted higher up, to the 9-10 kHz region, which improves perceived detail retrieval, speed, and extension. The treble’s prominence is also track-dependent; it takes a back seat on bass-heavy material but supports mid-centric tracks adequately.

Sonic Qualities & Genre Synergy

The RSV-MKII is not a detail-monster but a master of natural timbre and easy listening. It excels across genres thanks to its superb midrange, but its strengthened bass and softened treble make it particularly adept at certain styles:

  • Rock & Metal: Delivers raw energy and visceral impact without fatigue. The presentation feels like a polished live performance rather than a sterile studio recording.
  • Rap & Hip-Hop: Provides punchy, powerful bass. On rare occasions, deep male vocals can exhibit a slight fullness that borders on bleed, and distorted bass samples can sometimes sound artificially gritty.
  • Classical & Jazz: The bass weight adds a wonderful sense of depth, creating a more immersive and emotionally resonant experience especially with Chamber music. Strings have great texture. The refined treble handles brass instruments with sweetness rather than shrillness.
  • Vocals & Pop: Adapts flawlessly to production quirks, rendering vocals with nuance and intimacy without artificial highlighting. It conveys emotional intent superbly.
  • Electronica: The room-filling, toe-tapping low-end makes it highly engaging for electronic music, providing an ominous presence and physical weight.

Verdict

Initial disappointment that Softears had retuned a beloved reference IEM has given way to appreciation. The RSV-MKII is a different, but no less accomplished, instrument. Its timbre is more natural, its soundstage has greater depth, and its overall presentation is more musically engaging.

While I personally would prefer a slightly reduced bass emphasis, its execution is flawless. The physical and ergonomic refinements – the superb new nozzle, vented design, and excellent cable – are all unequivocal improvements.

Overall, the Softears RSV-MKII is a terrific product in the premium category, offering performance that flirts with flagship territory. It ticks nearly every box for a daily-use IEM and will likely serve as my personal go-to for the foreseeable future. It is an easier, more universal recommendation than its predecessor, especially for those who found the original lacking in bass impact or long-term listenability.