Been trying out my BA5 for a couple of days now.
First impressions:
BUILD - Shells look very nice and contoured, with pleasant material. They look as if they might be a complicated fit, but they are surprisingly comfortable. Comfort and seal is good out-of-the-box, and I have not engaged in cable-changing or tip-rolling. [Even though I bought this cable, I think, for the BA5:
https://www.aliexpress.com/item/4000141337661.html ]
The shell is reminiscent of the V90 in some way, such as its smoothness and material. Mine is a rich shade of black that glistens attractively, and there is a cool grille on the exterior. There is some isolation, but not much more than a V80 for me. The BA5 fits me much better than the V90. The stock cable has no microphonic issues, and isn't tangle-prone. It's worth noting that the seller shipped it pretty quickly following the 12.12 sale.
AUDIO - My first impression of the sound quality is that the BA5 is very CLEAR. Playing prog rock, jazz, and hip-hop at first, the BA5 separated elements pretty well. Vocals are usually distinct. In Yelawolf's 'Pop the Trunk,' the BA5 delivered less bass information than the V90. However, I found it easier to follow the vocals, and this was not an isolated incident.
Directionality or sound positioning is also pretty good, probably a result of the all-BA setup. I can actually tell that there's a bunch of BAs positioned all over, hearing the mixing coming from distinct locations. The BA5 predictably aces Bowie's "Space Oddity" in this regard. I find the BA5 comparable to the King Pro, here.
Tuning or timbre is relatively 'mature' as far as my IEMs go. It's not as 'musical' as the CNT-1, King Pro, or ZS7, and in this regard, it reminds me of the V90. This has advantages and disadvantages. I'm experiencing roundness and not peaks, which is good. It's a pretty smooth IEM, actually. On the other hand, I find that the treble in particular lacks 'sparkle' and air. The highs should be more emotional, at least that's my preferred tuning usually. I noticed this lack of emotion in the middle of "The Best of the Alan Parsons Project" album.
The instrumental strengths of the IEM, as far as I can tell, seem to be in percussion. Drums and other percussion tracks are crisp, and distinct. I think that they often have more impact than the bass. The BA5 reliably keeps the beat. In classical tracks, brass has some punch to it, although I sometimes find the strings a bit weak. The BA5 can render them as rich and full in Boulez's Rhapsodie Espagnole, so maybe it's a recording issue.
I wasn't sure exactly that the BA5 was _for_, so tried Daft Punk's Discovery album. Here, it presented the bass tastefully, but not too large, as in "Something about You." Synth instruments were handled well in multiple tracks, and of course the percussion was crisp.
In any case, this is a clear-sounding IEM that provides good separation and positioning. It utilizes many of the strengths that are associated with BAs. I think I'll try the music mentioned in the posts above, to see how the BA5 performs.