The Zaph Audio 5" mid can perform down to around an F3 of 55-65Hz in the old Philharmonic Audio MiniPhil (ported, sealed respectively). That's a $50 Driver. You think that the AT Mid can't deliver in Spades as low as 400Hz? (Which is the bottom of the Speech Band for all intents and purposes.) Now I don't know where they are crossing at, but the three higher end Mids that Salk has been using (Accuton, Audio Technogy, Eton) are some of the best on market. They will soon be adding the Ceramic SB Acoustic driver to that line up as well, from what I understand.
Remember, It's also not just about crossing to the woofer, but also the tweeter. If you've never heard a Dennis Murphy designed speaker, you need to. Of course, chances are, you'll not likely be able to listen to anything else again!