Peter Dicks and DDD Wave Converter

Whilst information on the Walsh driver can be easily found, I don't seem to find anything on Peter Dicks and his famed DDD Wave Converter as used on the German Physiks range. Tried AES but appears there is no paper on this. I believe that it is possible to convert a conventional driver by disassembling one and adding the directional cones and ancillaries on convert one to a DDD Wave Converter but need to know the physics to get the design to work.

Any thoughts on this?
 
Re: Peter Dick and DDD Wave Converter

amsci99 said:
Whilst information on the Walsh driver can be easily found, I don't seem to find anything on Peter Dick and his famed DDD Wave Converter as used on the German Physiks range. Tried AES but appears there is no paper on this. I believe that it is possible to convert a conventional driver by disassembling one and adding the directional cones and ancillaries on convert one to a DDD Wave Converter but need to know the physics to get the design to work.

Any thoughts on this?


I know Peter Dicks and have had some discussions on his drivers, many years ago. The DDD cone functions very much different then a conventional cone. Normally cones are designed to act as much as possible as a stiff piston. A DDD cone works, like the Walsh, by 'rippling' the wave across the cone to the surround. The cone flexes in a very defined way to do this. The material, geometry (angle) as well as the terminating surround are all quite different and I'm sure a 'conventional' cone will not function as a DDD.

Jan Didden
 
Re: Re: Peter Dick and DDD Wave Converter

janneman said:



I know Peter Dicks and have had some discussions on his drivers, many years ago. The DDD cone functions very much different then a conventional cone. Normally cones are designed to act as much as possible as a stiff piston. A DDD cone works, like the Walsh, by 'rippling' the wave across the cone to the surround. The cone flexes in a very defined way to do this. The material, geometry (angle) as well as the terminating surround are all quite different and I'm sure a 'conventional' cone will not function as a DDD.

Jan Didden

Jan,

Thanks for the prompt reply. Actually, I was thinking of using the magnets, coil and suspension and rebuild the cone, spider and ancillaries. A whole lot of machine work but I think it would come close to Peter Dicks's DDD. Now the problem is to get some literature behind the physics of the DDD.
 
What I find strange is that they use materials with poor damping like carbon and titianium. Maybe the "math" is to reduce the reflection problems to a single peak that can be notched out.
To avoid voice coil centering problems it may be wise to slaughter spiderless DC Gold drivers, expensive, but it will make life easier. If the bending wave is dead before it reaches the bottom I see no problem with a segmented diaphragm.
 
el`Ol said:
What I find strange is that they use materials with poor damping like carbon and titianium. Maybe the "math" is to reduce the reflection problems to a single peak that can be notched out.
To avoid voice coil centering problems it may be wise to slaughter spiderless DC Gold drivers, expensive, but it will make life easier. If the bending wave is dead before it reaches the bottom I see no problem with a segmented diaphragm.

I think they don't want damping in the diaphragm. The problem they have is to absorb the travelling wave at the surround to avoid it being reflected back up.

Jan Didden
 
planet10 said:
I've heard the DDD and it really is very good. A huge amount of work has gone into this driver to not just make it work but to make it work well...

dave


I actually worked for Peter Dicks in the early 90's, at NATO's European Headquarters in Mons, Belgium. We spend lots of hours listening at his chateau. I don't know how much money he spend on this, but it must be many 10's of thousands of Deutschmarks at that time. Ordering special-treatment titanium sheets at single sample quantities is probably more expensive than pure gold. He also had boxes full of surround prototypes, equally expensive. IIRC he was working on it for at least 10 years before the first acceptable prototypes. Then Holger Muller of Mainhattan Acoustics founded German Physics just to market the DDD's. But Peter Dicks didn't expect to break even in his lifetime. For him it was just the fascination in developing this.

Jan Didden
 
David,

I can only compare the DDD's (in a complete system) to the Wilsons I heard in Bandung; I don't remember if that were WAMMs.

No misunderstanding: the Wilsons sounded very, very good. That whole system sounded very lifelike and was surely one of the best I ever heard.
But I would think that the DDD's are probably just a bit more refined, maybe less overwhelming and therefore more convinving. These were DDD's with titanium foil cones; I haven't heard the newest ones with carbon cones which presumably might even be better.

Just my 2ct worth.

Jan Didden
 

EC8010

diyAudio Moderator Emeritus
2003-01-18 7:57 am
Near London. UK
It's quite easy to knock up a distributed mode loudspeaker. I made a pair out of modelling card and two nasty little 65mm drivers. Total cost was < £15 and the most expensive part was the card (about £10). Here's a measured response:
 

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EC8010 said:
It's quite easy to knock up a distributed mode loudspeaker. I made a pair out of modelling card and two nasty little 65mm drivers. Total cost was < £15 and the most expensive part was the card (about £10). Here's a measured response:


I take it that you show this curve as a deterrent ;) ?

Jan Didden
 
There is another way of doing this....

ues a standard voice coil and magnet assembly (best to eliminate the spider though). Connect the top of the voice coil to a tensioned plastic diaphragm install some form of dust cap. Now when you pulse the diaphragm a wave front is set in motion forward from the dust cap while at the same time the voice coil imparts a annular wave form which spreads out across the plastic diaphragm. The leading edges of theses two acoustical events are linked and in sink with each other. The end result is a spherical (reasonable fax) wavefront generated from a flat plastic diaphragm. It is the old ripple in a pond. Works like a charm if you juggle it properly. If any one wants to complain that it could not can not will not work because of so many reasons then explain how that german blathaller jig is selling for silly money. Give it a try before you say it wont because it will.
 
Re: There is another way of doing this....

moray james said:
ues a standard voice coil and magnet assembly (best to eliminate the spider though). Connect the top of the voice coil to a tensioned plastic diaphragm install some form of dust cap. Now when you pulse the diaphragm a wave front is set in motion forward from the dust cap while at the same time the voice coil imparts a annular wave form which spreads out across the plastic diaphragm. The leading edges of theses two acoustical events are linked and in sink with each other. The end result is a spherical (reasonable fax) wavefront generated from a flat plastic diaphragm. It is the old ripple in a pond. Works like a charm if you juggle it properly. If any one wants to complain that it could not can not will not work because of so many reasons then explain how that german blathaller jig is selling for silly money. Give it a try before you say it wont because it will.

Moray,

Does the Manger work in this way?

Jan Didden