Having spent more time with the BA5 I wanted to add to my initial thoughts about the earphone. I find TRN to be a very interesting company as their is no TRN sound, each release is something new and different and the BA5 is no different. On one of the other threads there was a recent discussion as to whether a single dynamic driver was better or a whether a multi BA earphone was better. I don't believe there is a correct answer to this question but it can not be denied that each has pros and cons. What I believe TRN did with the BA5 is to build a multi BA earphone that took into account the strengths of BA drivers and did not try to compensate in those areas where Dynamic drivers excel. Where the Blon BL03 is praised for Timbre, Tone and Coherency the BA5 has to be praised for Clarity, Instrument Separation, Balance, Soundstage and Quick Decay. Even though I like both of these earphones very much their presentation is very different.
Of the things I have noted about the BA5 since I initially received them, the first is what isn't there. The background is very clean, when the music stops the silence is notable. The second is the soundstage which isn't just wide but has good height and depth providing a 3D effect.
Although other earphones have more bass, the BA5 has good bass with good detail and quick decay. The balance between bass, mids and treble provides a full presentation where the bass is presented at a level that lets the mids and treble shine.
My listening preferences change with my mood. Some days I want to listen to the music as a single unit and at other times I want to immerse myself into the music, isolating and examining individual instruments. The BA5s level of instrument separation and detail allows you to easily isolate and examine each vocal presentation and instrument within the music.
I believe that TRN deserves a lot of praise for what they have achieved with the BA5.