Disclaimer: This set was provided to me by Surfans themselves, but all thoughts are my honest opinion after using this set for one week.
Also take notice that we all hear differently based on our ear anatomy, eartip used and individual sensitivity to specific frequencies, so what i may hear may not necessary be what you'd hear.
Specs:
Impedance: 20Ω
Sensitivity: 106dB
Connector: 0.78mm QDC
Drivers: 1 Dynamic driver + 1 Balanced armature
Cable length: 1.2m
Package and accessories
Surfans M10 comes with 2 sets of decent eartips (silicon and foam, 3 sizes of each type).
Silicon eartips are wider bore and short length, feel comfortable in ear and don't irritate my skin even during long usage.
Cable is below average, it's thin qdc style cable that is a little bit better than kz cable, it's lightweight but have angular shaped connector and could be uncomfortable if it would touch your ear.
Carrying case is of decent quality, has enough space to carry iems as well as small dac/dap.
Ergonomics
Iems themselves are lightweight, sitting at 4.74g without cable and eartips, shape is semicustom and may not necessarily work with your ear, also IMO it's quite wide.
Another thing i should point out is that stock cable force earbud in position that is extremely uncomfortable and I start feeling pain on my right ear after 20 minutes, changing cables to trn sea serpent fixed issue for me, but when i tried stock kz cable laying around and some random 2-pin cable it helped as well. IMO they should improve cable.
Sound
Personally, based on what I hear, it should be described it as W-shape well done, it has quite forward vocals without being sibilant, bass boost and good detailed treble extention.
Bass: Bass is fast and well controlled without lacking in quantity, bass sound similar to Letshuoer Astralis in quantity but a bit slower and with more noticeable air pressure, exactly what you can expect from difference between planar and dynamic driver, but unlike astralis because vocals are not recessed it doesn't overpower them and you can hear everything crystal clear.
Mids: To avoid sibilance they used specific trick with tuning - instead of peak at 3kHz for pinna gain they have 2.5kHz and 4kHz kHz peaks at around same level with slight dip at 3kHz, as well as dip between 4.5-7kHz.
Acoustic guitar, bass guitar and piano sounds clear and full bodied, both nylon strings, steel strings on guitar.
High: To restore some of details lost they boosted upper trable, it has another peak at 7.5kHz (it shifts based on insertion depth, but this peak is lower than 4kHz peak) and after this it smoothly decline before rolling off above 15kHz.
My measurements of this IEM aligned to 8kHz resonance peak
Technical Performance: It has good resolution, something you can expect from IEMs in similar price brackets.
Polyphia - Playing God - you can hear not only nylon strings but also fingers plucking them, decay sound natural even in more chaotic places you can cleanly distinguish everything.
DragonForce - Through the fire and flames, as well as Dream theater - Panic Atttack, even in most chaotic places sound doesn't transform in wall of sound but stays quite clear, even though it can't reach performance of something like Aful Performer 5+2 it isn't that far off.
Daft Punk - Giorgio by Moroder - testing layering, even close to the end on when everything could mesh together transforming into wall of sound on less resolving gear, you can still distinguish individual parts like cymbals, bass, etc.
Imaging: I think i better talk about imaging in context of gaming, i should say that it's a bit strange, in cs2 i cap pinpoint exact enemy position, including how far he is and if he is above or below me with high precision, but in war thunder sometimes i have problem distinguishing enemy sound from background noise and distance is a bit less accurate, i suspect it shows difference in how stereo audio in game is implemented.
Music used for testing:
Polyphia - Playing God
DragonForce - Through the fire and flames
Dream theater - Panic Atttack
OneRepublic - Artificial Paradise
Alice Merton - No Roots
Five Finger Death Punch - Wrong Side of Heaven
Imagine Dragons - Children of the Sky
OneRepublic - Sunshine (acoustic)
and much more...
Sources used:
Motherboard 3.5 output
Lethuoed DT01 PRO
TRN Black Pearl
Shanling UA7
Surfans X10
Conclusion
While I personally like this IEM (i though it would be bad iem, but it exceeded my expectations), i understand that it may be not for everyone, if you don't like vocal forward iems, something like Letshuoer Astralis may be better for you. But if you like exciting iems with forward vocals and detailed treble, this iem may be for you, also as most V shaped iems it's suitable for low level listening because we are significantly less sensitive to bass (low frequencies) compared to mid-range frequencies, and to a lesser extent, also less sensitive to very high frequencies. It doesn't need best source but i recommend getting decent dongle, with motherboard output treble get metallic timbre, with good sources high frequency sounds natural.
Surfans X10
Small Part about this DAC, it performed decent even though I had some issues, at 32bit 384kHz setting you get oversampling artifacts (I don't know if it's windows problem or dac having problem, with trn black pear I also have a bit of distortions, but they are less noticeable, and Shanling UA7 don't produce any distortion).
Noise floor is quite low, but with some most sensitive IEMs when using 4.4 balanced output you can still hear almost imperceptible hiss (you can't hear it when using 3.5).
When i changed settings to 24bit 192kHz issues disappeared.
It's good enough to properly power all IEMs I can imagine and overhead full-size planar headphones (Hifiman Ananda Nano in my case).
Also, small note, I feel like this source add some coloration to IEMs, it makes sound a tiny bit warmer (at least it works this way with Surfans M10, and it improves listening experience).
Pros:
+Good power output both 3.5 (111mW) and 4.4 (522mW)
+Screen
+Low noise floor
+Good Build Quality
Cons:
-No PEQ
-Strange behaviour at high PCM settings (might me problem with my system or I lost silicon lottery with this one)