Just a few scattered comments here and there on the boards and in PM. I'm waiting until after the meet where I get to hear it on the BHSE and a new prototype amp that someone's building. I've already measured the 009. The results are excellent - the most linear FR and possibly the best CSD compared to all other headphones I've measured yet.
Subjectively, it sounds a little bit bumped in the middle to upper midrange and tails off a bit in lowest octaves or two, but overall very smooth. Smooth in that I don't hear any abrupt changes in FR which makes it very "speaker" like since 95% of headphones usually have some nasty resonance nodes. Very fast in the treble, similar to O2 in clarity of fast percussion work. Overall slam is great.
There are some shortcomings with overall dynamics, lower bass slam, bass extension (which I already mentioned), and even ultimate low level information retrieval. I still think the BA + <insert TOTL dynamic> sounds more "involving" and "musical" (for whatever those two vague terms really mean), but I want reserve final judgement until I hear this thing properly powered. One person I trust says a DIY T2 does justice for it. But that is out of the question for me.
Thanks, I look forward to a comprehensive, subjective review. The one thing I always admired about Stax was the transparency from the mids up, having owned some in the '70s. I reckon they'll never have low bass.