The Kans, I know, are I.B.s (sealed boxes), and I'm guessing here that the Tannoys are not (don't know much about Tannoys). Could it not be than any I.B.s need a lot more welly to wake up? Certainly , all I've had did, incl. early Kans and SBLs (and even Briks) as opposed to ProAcs etcetera (ported).
This thread is becoming a wee bit technical for me (and that doesn't take much), and I haven't a clue what the ostensible contretemps is about. However, I have to acknowledge Dennis's written eloquence (once a teacher......)