phase plug design, simple or not ?

Trying to knock together a phase plug for the Funktion 1 Ax88 driver.

according to this the principle is not complex in terms of calculations. Its just a blocker for phase cancellation and thats it. high frequencies come from the centre of the cone, and the plug stops them crossing each other.

http://www.preference-audio.com/phaseplug.htm

So if this right, then all the the fancy angles on the F1 horns are really just dispersion. There is no real maths to the actual phase plug action itself ? All it has to do is prevent cross cancellation,and sit near the cone centre. 

I know there is the compression driver aspect to phase plugs in Compression drivers...

i.e.

but this does not appear to be present in the F1 driver. It just a cross cancellation plug and horn located next to the driver for wide dispersion. 

kevinmcdonough wrote: rogerharris wrote: So if this right, then all the the fancy angles on the F1 horns are really just dispersion. There is no real maths to the actual phase plug action itself ? All it has to do is prevent cross cancellation,and sit near the cone centre.  Well, in theory yes. In practice it will also affect the sound greatly, in subtle ways that aren't always predictable just going by the maths. Almost always takes LOTS of prototyopes and modifications to get a result. There was another thread over the last few weeks where (possibly Centauri again) was comparing lots of different phaseplugs on the same driver, all basically the same bit with the "ring" of sound output in different places. And was noticably different results for each one. k

Ill PM him about this. I think the problem he is having is that the plug is not right on the cone centre and the cones are not designed as a diaphragm in the first place.  

pfly wrote: F1 Axehead creates in essence a ring radiator, it matches path and time differences before the throat and eats away compression chamber volume. After the throat phase plug is part of horn expansion, at the same time taking care of even dispersion throughout the intended range of whole device and at the same time keeping horn profile in check thus making mad efficiency possible. It is possible that cone produces 10khz tone but it will probably be too narrow to be of any use whereas if you'd put horn in front of it, the horn would amplify (match the impedance between cone and air) certain fq range while attenuating others. Put it simply, horns generally make usable frequency range narrower but on the other hand make things more efficient. Here the real art of F1 starts, how they seem to make things possible no one else can, to get as much efficiency and clean sound out through that wide bandwidth as F1 Resolution mid devices do is pretty amazing.

Ok, back to drawing board. I thought i might be trying to simplify it. So basically the horn design is helping the driver become a ring radiator ?

http://en.wikipedia.org/wiki/Tweeter

Dome tweeter

A dome tweeter is constructed by attaching a voice coil to a dome (made of woven fabric, thin metal or other suitable material), which is attached to the magnet or the top plate via a low compliance suspension. These tweeters typically do not have a frame or basket, but a simple front plate attached to the magnet assembly. Dome tweeters are categorized by their voice coil diameter, and range from 19 mm (0.75 in), through 38 mm (1.5 in). The overwhelming majority of dome tweeters presently used in hi-fi speakers are 25 mm (1 in) in diameter.

A variation is the ring radiator in which the 'suspension' of the cone or dome becomes the major radiating element. These tweeters have different directivity characteristics when compared to standard dome tweeters.

so does the ring radiator horn design of the F1 also compress the sound or is it all about directivity ?

ok that explains it somewhat. So it looks as if the F1 is a massive paper version of this.

interesting plots of all this various stuff here

http://www.aeronet.com.au/waveguide.htm