Tannoy Stirlings on the way!

@mulveling 

Great write up.

My 1978 Berkeley's have the 15 inch alnico pepperpot driver but apart from the fact that I remember reading that they crossed over around 1kHz I don't really know that much about them.

So it looks as if the tweeter is covering most of the midrange, or am I missing something else?

My 1978 Berkeley's have the 15 inch alnico pepperpot driver but apart from the fact that I remember reading that they crossed over around 1kHz I don't really know that much about them.

So it looks as if the tweeter is covering most of the midrange, or am I missing something else?

Yep the alnico/pepperpot tweeter covers a lot of midrange. And the 15" woofer covers a lot of upper midrange! I think the woofer suffers some degree of "beaming" at that point, but at 15" diameter it's a pretty large "beam", and this transition at 1100 Hz is further aided by the controlled dispersion pattern of the horn tweeter. A pretty amazingly balanced and considered design, for having its origins in the 1940s!

The tweeter has a 2" inverted dome metal diaphragm and 2" voice coil, which is well suited to going down that low AND handling the higher power levels. Where it's less stellar is in hitting 20kHz and beyond. The GR series tweeters seem to be improved at this. The tulip tweeters use a smaller dome and can extend past 20kHz.

Interesting.  I thought all the Prestige GR models used alnico magnets.

@trentmemphis

Interesting. I thought all the Prestige GR models used alnico magnets.

Nope, in the last few modern series Tannoys, alnico models are distinguished by the pretty gold/orange colored horn (the strangely named pepperpot), with an empty/open throat until it reaches the back "pepper" holes drilled through to the compression chamber. The tulip waveguides are visually distinguished by their inner concentric circles, and always use ceramic magnets.

The good news for tulip driver owners is that replacement drivers cost a LOT less 😅 FYI I bought spare Canterbury GR drivers to the tune of $7K. The Glenair 10" tulips were like $600.

I'll be darned. You sent me back to look at the manual. Sure enough, it says the magnets are barium ferrite.  Dunno if that's the same thing you're calling "ceramic," but it certainly is not alnico.