The FIBAE7 is a very rich sounding IEM, a soulful and romantic presentation that combines power and energy with finesse and nuance. If you like a full, rich, natural and smooth signature with amazing musicality and great sense of pace rhythm and timing with no compromises on technical foundations then you’re in for a treat with the FIBAE7!
If you’re looking for a fun IEM with sound technical foundations that you can listen to for hours at times without any fatigue, then the FIBAE4 is definitely a must own in a collection especially in its price bracket! If you’re looking for fun tuning with more bite and a snappier attack then there are a few mid range IEM that could suit you more like say Earsonics Velvet v2 or - more pricey - the Earsonics Purple or Campfire’s Atlas.
The Black is appart in the FIBAE lineup, in that it’s based on a radically different design pattern - from the ground up. There is a lot of work into the technical design, especially in acoustics and it shows. It might be priced as an entry level custom IEM (and a mid priced universal) but it sure doesn’t sound like one! The Black mids are probably my favorite mids regardless of price or driver tech.