Yume

I jumped from the hype 4 immediately to a $1400 pair (SeeAudio Kaguya) and while they are more detailed, it didnt have the same “oh wow ive never noticed this sound in this song before” experience i had with the hype4. The best way i can describe it is everything has a more defined texture than it does with the hype4, no instruments mix or cover up the others at all, but the sounds were all already present and pretty well separated with the hype4. I dont regret buying a kilobuck set but i doubt I will buy another set of iems in that price range unless i demo them and discover a massive difference in sound.

Honestly they're both really fun for J-pop, at least in my opinion, based on my playlist. Maybe you can share some jp songs you use for reference? Both are fun and engaging iems with decent bass quantity(not basshead levels though). Not sure about the treble issue, but the yume sounds brighter yet not sibilant, while the May sounds shouty(compared to the yume) and may sound sibilant at higher volumes. The Mays have a rounder, deeper bass, and the vocals sound fuller. The Yume has a tighter, leaner bass while the vocals sound a bit digital(?) not sure how to describe it. It sounds different, like how warm iems sometimes color female vocals but the opposite. The biggest difference(aside from the price ofc) is in the separation and clarity, and how the sound is presented. The May(at least compared to the Yume) sounds like it's closer to you and makes it feel like everything is at your face. Combined with its deep bass and shouty vocals, it can sometimes sound overwhelming or too much in busy tracks. While the Yume has better separation between instruments and the vocals stay clear and well-defined even in busy tracks, the bass although not as deep as the May doesn't sound lacking at all. I think these factors make the sound wide and expansive.