I disagree Tam. When tweaking the crossover and later when experimenting with active, I did lots of measurement. They are putting treble out there right up to where microphone response falls off. Lack of Tannoy treble response is a myth. The fact is they are voiced to make music, not to compete with gee-whiz hifi speakers which overemphasise the treble region to make an impact.

I've actually tried four different brands of supertweeter with mine to see what impact that might have, in all cases the result was less musical.

There were speakers (Cambridge R50s - which I've owned - and various KEFs spring to mind) back in the 60s and 70s that did the extended treble response thing and none of them can hold a candle musically to the coherence and 'rightness' of a Monitor Gold.
I totally agree, Tom, but it's rather interesting when I swap from my Lockwoods and pop the Celestion 66s onto the end of the system... I can say for a fact that the 66s are defo more extended at the top-end, and in a way which isn't in the slightest "gee-whiz hifi"!

It's one of the reasons why I bought the 66s, as they have a totally different presentation from Tannoy DCs, but do the same 'musical thing' in their own inimitable way, which is equally as enjoyable.... It's nice to have a choice

Marco.