Softears RS10 and Cerberus

Sound Analysis – RS10

RS10 stands for Reference Sound 10 and is tuned to Moondrop’s VDSF target curve (which primarily takes inspiration from the Harman target curve) but has Softears’ own flavour and take on the curve. As per Softears, RS10 aims to reproduce sound of a mastering studio and was specifically designed to reproduce accurate timbre, imaging, soundstage and immersion of good monitors in a mastering studio.

RS10 has a bass shelf of around 6-7dB below 200Hz, very neutral and accurate midrange presentation, forward upper-midrange with 10dB pinna gain, clean and accurate lower treble and fairly neutral upper-treble extension and presence. RS10 is very well tuned and has a very accurate tonal presentation. It is more a direct refinement over the Moondrop S8 than Softears’ own RSV, which was a slightly warmer and easy-to-like musical take on the VDSF curve than a more neutral one like the S8. Compared to S8, RS10 refines technical performance significantly while keeping the signature mostly similar, except for the treble region. More on this later in the comparisons section.

Bass – The 6-7dB bass shelf is extremely well executed. It tastefully boosts not just the sub-bass and mid-bass but also a bit of upper-bass. I really like the precision of RS10’s bass response. It has really good attack, punch and rumble without ever overpowering the rest of the frequency range. The only thing it lacks is a bit of the soft, natural and musical character of a dynamic driver, which somehow the RSV and U12t were able to execute even though they too are all-BA IEMs. But on the other hand, I find RS10’s bass presence more sharp/precise and neutral compared to U12t’s, which is slightly more boosted for a more fun & dynamic listen.

Midrange – RS10’s midrange sounds clean, precise, accurate and is highly resolving with very good vocal and instrument definition. The lower-midrange presentation is very linear, clean and resolving without any muddiness or honk whereas the forward upper-midrange presentation of 10dB pinna gain helps in accurate tonal presentation. The same 10dB pinna gain can come off shouty if you prefer IEMs with warmer midrange with less pinna gain. But RS10 will definitely appeal more to neutral and technical performance heads. The sheer resolution, detail retrieval and tonal presentation in the midrange is of very high quality and a feat that is not as easy to achieve as one would imagine, even though RS10 is no affordable IEM by any means.

Treble – RS10’s treble is well balanced and has good extension till 20kHz. It has excellent clarity and is a very clean sounding IEM. RS10’s treble balance keeps tonality and timbre of instruments sounding pristine and accurate, without any harshness or sibilance. RS10’s 8kHz peak is a smidgen more than Moondrop S8’s which makes it sound ever so slightly brighter in the region in comparison but also improves on micro-detail retrieval ability over the former. RS10 is neutral with its upper-treble presentation and isn’t as airy as the U12t, which has significant boosts in upper-treble to add some air and excitement into an otherwise warm signature. RS10 is actually the more neutral sounding IEM in the upper-treble region but U12t’s highly attractive airiness makes it a more fun take on neutral.

Technical Performance RS10 has a good soundstage with good width and depth but doesn’t beat 64 Audio’s similarly priced U12t’s soundstage, which feels slightly roomier like a performance stage compared to RS10’s picture of a very neutral and well treated studio room, which is actually what Softears designed it to do. RS10 has very good detail retrieval and resolution throughout the spectrum while keeping the tonality sounding natural without over boosting of treble, which is what good tuning is. Imaging is very good and so is the separation.

Drivability – RS10 definitely needs more power to drive than the average multi-BA IEM. I’m able to drive it to a good loud level with my MacBook Pro and OnePlus 7 Pro phone by almost maxing out the volume, at around 75-80% on my MBP and 85-90% on my OnePlus. A DAP with good output power like the R6 2020 or DX160 will be able to drive it with way more ease. Even though I didn’t have any problem driving it with these sources, just keep in mind that RS10 does need good juice, especially if you feel your portable sources are on the weaker side. 

Softears RS10 + Case


64 Audio U12t – IMO, U12t is the default competitor when it comes to best IEMs at the $2000 mark and also RS10’s direct competitor as a reference IEM. Both are available as CIEMs, so they are targeted at both audiophiles as well as pro-musicians/engineers. When it comes to reference IEMs, RS10 is a more neutral, precise and clean take on a reference IEM whereas U12t is a slightly bassier, warmer, fuller and a relatively more musical take on a reference IEM. U12t has a bigger bass shelf by around 2dB and slightly fuller instrument body because of slightly fuller lower midrange presentation compared to RS10. RS10 sounds slightly leaner in comparison but has a more neutral and linear bass and lower-midrange presentation. RS10 has more accurate upper-midrange presentation with stronger instrument definition owing to it having more pinna gain at 3kHz but can also come across shouty to people sensitive to this region in comparison to U12t, especially when listening to them at louder levels. Even though RS10 is more accurate in its midrange presentation, U12t is a happy medium between having a fairly accurate upper-midrange presentation and an easy signature. RS10 is slightly brighter in lower-treble at 8kHz whereas U12t is much airier and sparkly up top in the upper-treble region. U12t can be considered a slightly V-shaped take on a reference IEM and ends up sounding more sparkly and exciting up top than absolutely neutral. RS10 is relatively more accurate and neutral in its upper-treble presentation. U12t has a bigger and roomier soundstage with slightly better resolving ability. It resolves reverbs in songs slightly better than RS10 and portrays a better sense of space in comparison. RS10 is no slouch but does fall slightly behind U12t in this regard. As I previously said, U12t’s soundstage feels like a roomier stage space compared to RS10’s picture of a very neutral and well treated studio room. U12t has a slight upper hand in image placement because of its roomier soundstage presentation. RS10 has more forward and stronger instrument definition but U12t makes up for it with good resolution, though both resolve similarly well and have very good micro-detail retrieval capability. At the end of it all, RS10 is a cleaner, more forward sounding neutral reference monitor whereas U12t is a slightly v-shaped/musical take on a reference signature with a roomier soundstage. You can find U12t new for around $1600 during sales and even lesser in the used market, which makes its value proposition quite attractive. If Softears can do similar sales throughout the year and discount the RS10 similarly or even more handsomely, it will always remain a competent competitor as a reference IEM to the U12t.

Lime Ears Pneuma – Pneuma and RS10 have the same amount of sub-bass with Pneuma’s bass switch off but Pneuma has a bit more with the switch on. Pneuma has more mid-bass as well as upper-bass and is tuned to be more fun and punchy than neutral. Pneuma has slightly fuller instrument body because of its 250-500Hz being slightly north of neutral whereas RS10 is more linear and neutral in the range. RS10 has more upper-midrange pinna gain and as a result, slightly forward and stronger instrument definition compared to Pneuma, but just by a little. In treble, Pneuma has its prominent peaks at 5kHz and another one at 10kHz whereas RS10 has a single lower-treble peak at 8kHz but is airier and better in its upper-treble presentation in comparison. Pneuma has a slightly wider soundstage but RS10’s is deeper. They both have equally competent technical performance. Both resolve very well and have good separation between layers. Both are very competent IEMs and choosing one over the other will probably come down to personal preferences, tastes and what one wants out of the IEM – Pneuma is a more fun sounding IEM whereas RS10 is the more accurate and neutral one.

Moondrop S8 – RS10 is a direct refinement and upgrade over S8’s sound signature and technical ability. They have similar-ish tonal balance but RS10 has slightly more lower-treble and ends up sounding slightly brighter and more exciting musically as a result.  RS10 has better instrument definition, imaging as well as macro and micro detail retrieval. It is able to resolve the small nuances and background information in songs better.  Even though RS10 is definitely the better IEM, S8’s value proposition is definitely better.

Softears RSV – RS10 is more neutral, cleaner and more refined whereas RSV is a warmer and slightly more musical take on the VDSF target in comparison. RSV has slightly fuller instrument body whereas RS10 has slightly more presence in the 3-5kHz and more lower-treble presence. As a result, instrument and vocals sound more upfront and defined in RS10 and sound warmer and a bit more romantic (for the lack of a better word) in RSV. RS10 has better overall technical performance – instrument definition, imaging, micro-detail retrieval and separation between instruments.

Page 3 – Cerberus – Sound Analysis, Comparisons and Conclusion.

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