The Coles super tweeters in my BC2's do still work, although they're wired out of phase with the HF1300 in an attempt to reduce the 14KHz resonance in the Celestions.. To be honest, they just help hf dispersion a tad, but little else..
I read and saw measurements on the Tannoy super-tweeter pods, which actually came in at a perfectly audible 8 - 10KHz and only went out to 28KHz or so before rolling out. I suspect their main function is to smooth out the wayward pepperpots in the main drivers or, bearing in mind the prestige series sound so mellow, to liven things up a little..
I can't go on and I can't go back, I don't feel so matter of fact,
I tried and tried to make good sense, What's the good to try it all again?