Kevlar vs. other materials (1 Viewer)

[Dwayne Smith]

What is the value of Kevlar vs. other materials when used for a speaker driver? I see Kevlar touted as a specific component and I don't know if it really means anything of if it just sounds good because Kevlar's cool.

 

[John Garcia]

Kevlar is stiff and light, so it can move fast and far without changing it's shape significantly. And it looks cool too

 

[ChrisWiggles]

FYI kevlar is not very stiff at all. As for kevlar in drivers, I only know B&Ws little explanation. Sounds neat, anyway. Regardless, drivers are made of all kinds of things, in all kinds of good and bad drivers.

 

[Chris Quinn]

I've heard that Kevlar doesn't stand up long term to the fast vibration/flexing of a speaker. Anybody know more about that?

 

[Mark Danner]

Never heard of Kevlar not holding up. Maybe thats why B&W uses it as a mid-range and not for the low end. Hey at least you can say that you have bullet proof speakers.

The stiffer drivers (metal) give you better precision and transparency. The softer materials give smoothness. They say Kevlar gives you both.

The Kevlar that is weaved for speakers is very stiff.

 

[Chu Gai]

Well it's more complicated than that. If we just look at Kevlar by itself, it's not a particularly stiff material. A property of Kevlar is that it's not so easy to stretch. Manufacturers layers of Kevlar and separate them in some controlled fashion. No doubt you might've seen phrases like Kevlar honeycomb structures. As the driver vibrates, the various tendencies for the material are transformed into stretching forces. Since we've got Kevlar, it resists these forces and what we have is stiff material that's also lightweight.

One feature of this approach is that the bandwidth of drivers are greater than that of other drivers of the same size.

However, there's often no free lunch. In the Kevlar composite design as well as other designs that involve composites, one also finds that the frequency response is not smooth and can have rather pronounced peaks and valleys which well made drivers like polypropylene don't have.

So here we have a driver, stiff and light, however one needs to find some way to deal with these resonances. It's my understanding that B&W apply some sort of compound to the drivers to control these resonances. However, this then reduces their bandwidth a bit.

No free lunch :frowning:

 

[Mark Danner]

Yeah I should have said that Kevlar falls more in the middle between metal and polypropylene type drivers. Bad choice of words on my part.