@ruthieandjohn
I've seen your profile and you have Heaven VIII so you want to know the sound of FI-BA-SS compared to that?
Short comparison (used Mojo, Mjolnir 2, iPhone 6 Plus (direct), oppo HA-2):
Heaven VIII: Warm smooth sound and bit sparkle and have some etching (outline) in voice or instrument. Bad staging.
Vocals are so big in size and like singing sticking on your face. Kind of warm, smooth, relaxing but fun sound, but sound is not natural especially for classical music (especially for flute, the hardest sound for audio to reproduce).
Plenty bass but not good punch. Reminds me of Kaiser 10 though not the same. Like not so hot and not so good bass Sonorous VI.
FI-BA-SS: Extremely revealing. Direct sound. Transparent. Tight, slim, deep, heavy and punchy bass. Cymbals and brushes? get prominent and in some tunes too much combined with slim bass.
Vocal and acoustic instrument sounds really natural and realistic. Nice staging. Adequate sized vocal.
Revealing sound reminds me a bit of STAX SR-Omega (original model which I own). However, I don't know why but bad matching with Mjolnir2 (bass becomes small and dull)
For me, it's a special IEM and really engaging and sometimes make me even tear, but not daily IEM since it's somewhat fatiguing for me.
E3000: Decent modest sound like 2 channel audio. Natural sound and nothing special in good meaning and bad meaning as well. Scales well with amp.
Sounds fantastic on Mjolnir 2 with nice punch and natural sound. However, with some amps like direct out from iPhone 6 Plus, music sounds slower.
Soundwise,I like it the best of the three for daily use regardless of the price. Sounds a bit like ETHER Flow on Mjolnir2. Hardest to drive of the three.
Please keep in mind FI-BA-SST is much warmer than FI-BA-SS (I compared it and felt SST more like "normal" IEM) and AKR02 is said to be warmer than FI-BA-SS as well (I haven't heard AKR02 though).