Tannoy Stirlings on the way!

It's a certain sound right? I've been curious about how the wave guide could take over at like 1000 hz in some models? I like mids with PUNCH but I've also heard pure horns sound so beautiful that I would sacrifice that punch. Is that kind of the case with Tannoy?  

It’s a certain sound right? I’ve been curious about how the wave guide could take over at like 1000 hz in some models? I like mids with PUNCH but I’ve also heard pure horns sound so beautiful that I would sacrifice that punch. Is that kind of the case with Tannoy?

@bjesien

The Tannoys which crossover at 1100 Hz use the older "pepper-pot" waveguide an alnico magnets rather than the newer "tulip" waveguides (which cross over higher) with ceramic magnets. The pepper-pot’s tweeter diaphragm is a replaceable part strapped onto the back of a compression chamber. The actual horn/waveguide is steel and somewhat substantial. The tulip’s replaceable tweeter includes the waveguide, which is much shorter and lighter (a few inches). Pepper pots come only in Kensington, Canterbury, Westminster, the Definition 10A, and I believe (maybe) a special very limited run of Turnberry (normal Turnberrys are tulip). The old vintage Tannoy drivers - Black, Silver, Gold, HPD - are pepperpots w/ alnico magnets. Tannoy switched to ceramic magnets (like everyone) around the 70s/80s when there was strife in the Congo and Cobalt supply went out. I guess the more compact ceramic magnets opened up more design possibilities which eventually led to the tulip design? Also, ever since the 80s, alnico is EXPENSIVE.

For comparison, a full replacement Glenair 10" tulip driver (woofer and tweeter) cost about $380 whereas a full Kensington 10" pepper-pot driver cost a few thousand. Why the expense? They have a huge alnico magnet basket on the back: the pepperpot and compression driver chamber operate inside this magnetic flux, which they share with the woofer coil (I think the pepperpot itself serves as a pole piece to focus the magnetic flux? magnets are still a mystery to me lol). The tulips use regular (and I believe separate) ceramic magnets (cheap), with these waveguides and magnets being much shorter. I believe the large alnico magnet ALSO dictates the low crossover frequency of these models - the long length from the alnico magnet and pepper-pot horn should match the half wavelength of that 1100 Hz crossover frequency (about 6 inches), so that by simply reversing polarity of the tweeter wires it can be in perfect phase with the woofer at that frequency! This gives these Tannoy drivers "phase coherence" at crossover without ANY added crossover complexity. Very cool.

As for the pepper vs. tulip’s impact on sound? Hard to say for sure across multiple models, as each cabinet design and driver size (not to mention crossover) has quite an impact on a Tannoy’s overall sound. What I’ve noticed is that the pepper designs have a more vibrant, rich, lively sound, especially in the midrange. The tulips are perhaps more technically neutral and even-handed. Certainly some might prefer tulips - but I find the pepper’s sound more exciting, warts and all: they can bite your ears with a couple treble peaks if you’re not careful - or even if your are careful, haha. The Canterbury SE is an example of a pepper driver with a darker overall voicing (the Canterbury GR, Kensington SE and Yorkminster SE are not dark like this), but the vibrance of the pepper pot still shines fully through in any case, so long as you don’t suffocate it with bad gear pairings. The older pepper pots before GR series had trouble extending to 20kHz, so you see these frequently paired with supertweeters - make no mistake, the Tannoy supertweeters have a very noticeable effect on the audible range (one which you may or may not like)!

@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.