Gotta update this. And this is why I try to be careful in the early stages, as although I always have a decent handle up front, the tiny nuances start to become much more apparent over time.
So I would scrap that the Expanse is a bit ahead resolution wise. They are both phenomenal at resolution and all of the detail in each, with each song, is apparent. What I am finding rather, is that the Expanse is a just a bit more forward--just a bit. And so the midrange, and particularly vocals, are a bit more in your face. In addition to that, the Expanse is definitely less spacious and more in your face in a "Utopia kind of way", although to be clear nowhere near the level of the Utopia. So at times, this more in your face sound can make details feel more apparent. For perspective, the CA-1a's positioning feels just about neutral, not recessed at all (more forward in comparison say to the x9000 or TC I.E.), but overall a bit spaced out and not as up close in your face.
However, the tradeoff here is the spacing. The single thing that is blowing my mind just a bit right now is the soundstage of the CA-1a. It is one of the best I've heard. It feels so spacious, so natural, and the imaging within it is just insane. From what I have heard, only the x9000 (admittedly can feel a bit artificial in doing so), Sr1a and SGL Sr (This is also a wow factor for the R10, but being closed it simply is a slight step behind all of these). do this at this kind of level, at least to my ears. So although things aren't as in your face or condensed like with the Expanse, you can very clearly pick out where every sound, instrument, etc is coming from as if you could reach out and touch it, in a way that the Expanse cannot compete with.
This and the better bass impact would put the CA-1a ahead of the Expanse overall to me, but I do find them to be close, and there are times I prefer the Expanse's presentation, especially with vocal heavy music. The bass is only a bit stronger, both with a smidge more impact and perceived quantity, but it matters a lot imo. You can listen to genres like rock, hip hop, etc. and not feel a deficiency. That is not the case with the Expanse or the Sr1a. It's also not the case with the SGL Sr., at least to my ears. (To be clear, you can still enjoy other aspects of the music with these genres, but for me, I simply avoid and turn the speakers on lol)
Also did some comparisons with the SGL Sr. last night and it was really interesting, taking one more day today and I'll follow up here at some point. But as a heads up, to say I am impressed by these headphones is an understatement. They will be up there in the ranking overall.