Some clarification... my personal review is amateur(mostly my hobbit and sharing thoughts with my pal) and not professional. Mostly based on initial impression before and after burn-in (Which mean I listen to songs of genre with no EQ setting, same player at the same volume before and after burn-in to compare any difference). If you are interested to know a little more regarding KZ upgrade cables, please look at my ZS10Pro review. In general, what I find is similar when using different "upgrade cable", so I will not repeat here again.
Since I own both C10 and ZS10Pro, I uses ZS10Pro as the day-to-day iem for the more accurate replication of frequencies and wider soundstage. But when it comes to songs relying on vocals, such as live/acapella I prefer to use the C10 for the fact of close to unnoticeable sibilance and exceptional clarity in the mids
As per my review with the KZ ZS10Pro, the accessories including the stock copper cable is pretty decent. But I would have "expected" something more from the middle range products. Maybe the silver-plated 4 core?
Bass & Sub-bass (9/10)
Based on my listening, the bass is not as strong as the ZS10Pro. But I still give it a 9 because in no ways it feels lacking. In fact due to the nature of lesser bass it does not make your head thumps as if you were having a headache. After burn-in: the bass seems to become slighlty more prominent.
Mids & Vocals (9.5/10)
I love the mids and vocals! Both male and female. It sounded very soothing, hardly hears any sibilance at the higher mids (which is pretty common) unless you are giving special effort in listening. Great clarity, managed to pickup breathing in songs which I did not previously realised was there in other earpieces I use. After burn-in: Might be due to stronger bass and highs, the mids and vocals does not stand out as much, but the clarity is still very good, made this statement for I listened to songs with lesser bass/highs and the vocals still *thumbs up*
Highs & Treble (9/10)
I tried listening to some classical and symphony. How should I put it? Felt like a live performance/recital. I mainly listened to Grand Piano and Violin pieces. The soundstage is wide, allowing accurate reference of where the source was. Simply put, LIVE experience. After burn-in: As mentioned, there is a increase in highs and treble making pieces especially the classical more "eargasmic" and of course in turn, make the iem feel really classy!
This earpiece is really sensitive. Like the KZ ZS10Pro, I put the volume at only 25% when typically it is around 32% for the older/less sensitive KZ earpiece. EQ in my opinion is more sensitive in C10 compared to ZS10Pro, in fact I have a hard time trying to get a nice EQ on my AP80 that I gave up (too sensitive hahaha). My life would be much easier if the dB were in +/-0.1 interval instead of +/-0.5. I give it a 9 simply for the fact that using a professional application with more delicate interval, you can acheive much more.
Slightly less heavy than ZS10Pro, thus making it less stressful on the ears. Tucked well in the ears with ergonomic design, comfortable to wear for hours. Does not have the warm sensation even with prolonged use.