Thanks for all the comments. I'm going to venture a guess as to the source of the observed differences between the HT1 and towers. First, the matter of "bloom" almost certainly has to do with the woofers, not the tweeters. As I've commented before, the W18 has a unique midbass presentation. It is, depending on the listener, either extremely realistic, or, alternatively, "thin." I think I belong in the first camp. The CA15's have a little more warmth in the midbass. Overall, I think the CA15 has less "warmth" than most other woofers, but I can hear the difference when comparing the W18 and CA15 under carefully controlled conditions. Second, the HT1 may well have more detail at the very top of its range. That's not because the ribbon has less "distortion" in the traditional sense. The 0W2 actually measures better in terms of harmonic distortion. But the top end of the G2 ribbon is more extended, and its very small moving mass may confer some transient advantages, although that's controversial. Frankly, my main goal with the towers was to maximize bass performance in a small foot-print speaker, and achieve as clean a midrange as possible. I also wanted the highs to be at least very good, which is one of the reasons I chose 3/4" tweeters, but I never expected to equal or exceed the ribbon designs in that department.
