The "Real" Aerogel

[gary f]

Look at this!

http://www.unitednuclear.com/aerogel.htm

World lighest solid. 1000 times lighter than glass. 3 times the density of air!
Can't wait for those Aerogel cones to come out.

F
(from J-Walk Blog: http://j-walkblog.com/ )

 

[inertial]

Hi,
Yes, I remember that material. I think it can be amazing for a cone!!
Why not one serious designer/factory have employed it?
Cheers,
Inertial

 

[bikehorn]

doesn't Audax have some sort of Aerogel products?

 

[quickshift]

Why not one serious designer/factory have employed it?

The liniked page says it shatters and absorbs moisture - that'll be a challenge.. Maybe they could sandwich or seal it with really thin aluminium or something to make it moisture proof?

Maybe they could try vapour plating it with iridium - it would look really cool too then

 

[dnsey]

Going by the price of the 'samples' (which appear to be offcuts or rejects of some sort), the speakers wouldn't be cheap

 

[inertial]

perdone me, guys

Quickshift,

Foam surround also shatters.........performance have a price.

Dnsey ,

are maybe diamonds and berillium cheaps?

Cheers,
Inertial

 

[SY]

doesn't Audax have some sort of Aerogel products?

Different. Audax's HDA cones appear to be a syntactic foam made from expandable microspheres (Expancel).

 

[quickshift]

Quickshift,

Foam surround also shatters.........performance have a price.

Yeah, true. The shattering problem they could maybe get round by tellling people to be really careful not to touch the cones and fitting some sort of rigid grill.

It's the moisture absorbsion that's a problem, I wouldn't really want the mass of my driver cones changing with the weather

 

[inertial]

Quickshift,
You are right, but I think ESL also "attract" moisture, and the world is full of ESL.
Joke apart, I think a serious experimentations could be foundamental to "solve" this problem. Really this aerogel seems to me very promising. We hope!
Cheers,
Inertial

 

[chillysalsa]

There are a few types of Aerogel listed on Matweb, but I think the lowest density one is Silica Aerogel:

http://www.matweb.com/search/SpecificMaterial.asp?bassnum=C5MTO1

Unfortunately it's stiffness is very low: < 0.01 GPa

worse than most rubbers...

So maybe it could be a good material for the surrounds, but not the cones.

It WOULD be interesting to make a sandwhich composite of:

carbon-nano-tube sheet : Aerogel: carbon-nano-tube sheet

There is a company that has found a way to make paper-thin sheets of the CNT material pretty cheaply. That would probably be quite the intresting cone material.

If anyone can find the best analytical expression for the IDEAL stiffness to density ratio, I have access to another huge database of materials and alloys that will have the highest ratios.

 

[inertial]

Hi chillysalsa
please correct me if I am wrong, but stiffness/rigidity of the "cones"
can increase enormous with the thickness........
Cheers,
Inertial

 

[soongsc]

If anyone can find the best analytical expression for the IDEAL stiffness to density ratio, I have access to another huge database of materials and alloys that will have the highest ratios.

For ideal piston action, the higer the stiffness to density ratio the better. Mosture attraction is part of density variation, but could probably be solved using very light coating.

 

[sardonx]

that stuff is really cool

 

[kelticwizard]

There is the small matter of the fact that a midrange or bass cone requires some weight to bring the Fs down to a workable level.

The lightest, stiffest cone is not necessarily the best cone, if you want decent bass perfomance.

 

[el`Ol]

The von Schweikert speakers have midrangers made of paper aerogel, but stiffened with carbone fibers. I ask myself, whether this would give good fullrangers (unstiffened).

 

[soongsc]

The von Schweikert speakers have midrangers made of paper aerogel, but stiffened with carbone fibers. I ask myself, whether this would give good fullrangers (unstiffened).

If it attracts humidity, then it would be a problem for high fidelity full range drivers.

 

[AndrewT]

Hi,
why think of "cone".
The b139 and a few others used a block of expanded polystyrene as the air mover. It too was sealed with an alloy membrain.

Maybe a silicon aerogel block could be used likewise.

If our new gel was half the weight and twice the stiffness of polystyrene then it would give a significant advance in most performance parameters.

 

[el`Ol]

If it attracts humidity, then it would be a problem for high fidelity full range drivers.

I have made good experiences with humid cones (glycerol to attract water).

 

[KozmoNaut]

Just popping in with a cool fact about aerogels:

"Aerogels by themselves are hydrophilic, but chemical treatment can make them hydrophobic. If moisture is adsorbed, they will usually cause a structural change of contraction etc. and deteriorate; however, degradation can be prevented by turning them hydrophobic. The aerogel which has hydrophobicity to the interior can prevent degradation, even if a crack reaches deeper than its surface, compared with the aerogel that was turned hydrophobic only of their surface. Hydrophobic treatment makes processing easy because it allows the use of a water jet cutter."

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

So the only thing standing in the way of a good aerogel-based DIY driver is cost (who da thunk it?)

 

[ScottG]

There is finally a commercial product based on aerogel. Its intended use is for exactly what it should be used for: Insulation. However that doesn't mean that this product couldn't be constrained between two layers of a thin light rigid material.

http://w1.cabot-corp.com/controller.jsp?N=23+4294967102+1000&entry=product