"W" Sandwich Structure Speaker Cone/Speaker Cone Profile

Maybe one day I will scan the article.

But you can buy the article here

https://www.aes.org/e-lib/browse.cfm?elib=1505

Here with carbon
https://www.aes.org/e-lib/browse.cfm?elib=5236


AES E-Library​


Sandwich-Construction Loudspeaker Diaphragm with Foamed High-Polymer and Carbon Fiber​





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Acrylic foam is used for the core and carbon fiber for the skin material of a loudspeaker diaphragm to achieve more rigidity, lower density, easier formability, and a higher Young's modulus. Unlike a honeycomb construction, this diaphragm material is relatively easy to form into a curved cone shape. The new diaphragm is at least 300 times more resistant to bending than a paper diaphragm, while nearly equal to paper in internal loss characteristics. The importance of diaphragm rigidity is confirmed by modal analysis and tone-burst tests.


Authors: Taguchi, Sadao; Watanabe, Toshio; Takahashi, Eiichi; Takahashi, Susumu; Tanaka, Susumu
Affiliation: Sansui Electric Company, Ltd., Tokyo 168, Japan
JAES Volume 34 Issue 11 pp. 895-904; November 1986
 
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Glue is important if you target CLD behavior. It is where most of the dampening happen ( by shear).
It depends of your goal/target: if you want to increase rigidity of membrane it might be a second factor, if you want to do this AND increase damping then it's not second anymore imo.

It's the dampening layer and it's interaction whith material used for sandwich which are the important point into a CLD approach.
 
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OK, both nitro cellulose and Pattex do some damping.

You can use the glue named in German Anlegemilch (nitro cellulose) as slight damping for paper cones. You see it on this the whizzer cone of this Fane Sovereign 15 300tc. And on the other Foto as a product from dukatshop.

I think that the aluminum does some damping. In my eyes it's the dominating factor.

It prevents from big resonance amplitudes.

The paper core itself has damping characteristics.
 

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I want to know how the speaker cone profile can affect the sound performance.

The speaker cone profiles I know of are:

Concave cone, widely used for Subwoofer, Woofer and Mid-Ranger.

Dome cone, often used for Tweeters and a few Mid-Rangers.

Flat cone, somewhat unknown, used for Woofers and Mid-Rangers.
Nawi is the most stable cone.

But honeycomb structures are difficult to implement into this structure. Therefore often flat cones are used.

So nawi paper cone with sandwich aluminium foil is a good stiff structure.

https://www.radiomuseum.org/forum/technik_der_lautsprecher.html
 

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Hello, I've read a lot about sandwich structures and some renowned companies have used them.

I'm currently working on a project of mine to make sandwich cones for my speakers.

The materials are:
Faces: Kevlar carbon fiber hybrid
Core: Low density expanded polystyrene (LDEP)

I want to know if there is another sandwich structure or better material than those I mentioned.

Currently I think the best sandwich structure for speaker cone.
Kevlar carbon and foam make the most stable ones.

However in listening tests I was quite happy with paper and aluminum. DSPed and so linearized it was good for fullrange drivers, too.

Harder cones are for classical multi way speakers good.