Yes but to be technical I must digress, I don't think the EX700 is sibilant, at least not like the CK10 or the SA-5000 which is what I call sibilant, especially the SA-5000 where "s" sounds are actually resonating into your nasal cavity but I could live with it it was pretty cool.
The EX700 is just harsh in a dissonance of the mids kind of way, which becomes literally deafening with extended use, it's literally impossible to listen to the EX700 with sony hybrids, flat eq, and high volume, impossible, after half an hour my ears are ringing, but I have learnt to circumvent this flaw with decored Shure Olives tips and eq'ing, and now I just get the best qualities out of them which is excellent transparency, tonality, decay, resonance and sweetness/clarity which is what I attribute to the 6kHz FR boost, but I do find the imaging really quite weak especially on the Y axis, and I certainly miss the flat-FR of the ck10. If I could sum up the EX700 in a few words I would call it the "harmony of dissonance" IEM, or "the deceitful angel", whatever Sony has magically done to the housing or driver of the EX600/1000 it seems to have exfoliated into the harmony of resonance.
There has been some discussion on the FR graphs of the EX700/600/800/1000 created by sonove.angry.jp, mostly along the lines of "what was Sony thinking?" with the 6kHz boost, but it is now clear that that boost is intentional, as we can also find it in high-end custom IEM's like the Rooth LS8 which even goes over and beyond whatever Sony was thinking with that SS.
The most interesting graph to me was the EX800ST, which looked a bit more well-tapered almost like a perfect sine-wave, but he was using "Sony Hybrid S" and changing tips will change the FR a bit, and then source synergy is important too, I do most of my listening with the Teclast T51 which has a good synergy with the EX700, another strength it has, source transparency, I can now hear the difference between my laptop and T51 clear as day, which was much harder with the ck10 as it is more forgiving and just takes whatever signal it gets and says "let's ck10 this", whereas the EX700 is let's the signal shine through, albeit it is stained glass.