**** 4in1 impressions:
- WOOF are these hot on the treble. Like, pierce your eardrums with a sewing needle hot.
- Sub-bass, not bad but it seems like everything after 20hz up to 200 is lacking. No worries about any sort of midbass hump here.
- Switching to narrow bore tips (Trinity Kombi) helped tame some of the highs.
- After 30 hours of burning the sibilance I heard initially seems to have disappeared.
- Soundstage is above average, but sound is still "inside of the head"
- I find myself constantly fiddling with the volume level. Usually due to too much sizzle in the treble on various tracks or not enough bass on others.
- With the cable included from NiceHCK these are a little harder to drive than the usual IEM. I'm up around 45-60 on my LG V10. Most IEMs I'm never above 40 or 45 on the volume.
- Acapella music is fantastic with these. I hear overtones that other headphones don't accurately reproduce.
- Dance Music just isn't any fun with these. I need more bass.
- Rock...OUCH. I couldn't do it. The hi-hat and crash cymbals about sent me through the ceiling.
- Jazz...nice...very nice.
- Detail, instrument separation, aural texture, all are way above what I would expect for headphones that cost less than $30.
The **** 4in1 has all of the detail and treble of the Vivo XE800 without being so shouty in the mids.
Overall, if you aren't a bass head, and you can deal with some serious treble, I doubt you'll find a better headphone for you right now. If someone could take the clarity and detail of these, and match them with the bass and relaxed nature of the TFZ Series 5, I would have my end game IEM.