I know it dampens the paper cone unwanted vibrations. Something like the soundproofing sheets used in car audio
But it works?
But it works?
The primary benefit would be that it increases the mass of the cone, which decreases it's resonant frequency. With a lower resonant frequency the woofer may be better able to reproduce lower frequencies. I assume it is adhered with glue, like rubber cement, which would also serve to dampen and stiffen the cone. Nasty way to do it though, probably looks like heck and may or may not make a difference worth messing them up.
A lot would probably depend on the 'bonding glue' used, plus of course the actual thickness of the foil itself.
Yes, it would lower the resonant frequency, and sounds like a bit of 'fun experimentation' with a low cost speaker 🙂
Yes, it would lower the resonant frequency, and sounds like a bit of 'fun experimentation' with a low cost speaker 🙂
With a soft sort of glue you could sort of get what's referred to as a constrained layer construction. This is usually two stiff outer layers with an absorptive lossy inner layer. The inner layer is in sheer when the assembly is bent, and the friction of that layer in sheer absorbs energy. So that could potentially make the driver operate more like a piston with less flexing and reduce the Q of cone breakup resonances.
The added mass will lower the output of the woofer in the mass controlled upper frequencies, leaving output at the suspension controlled bass frequencies about the same.
A larger box or softer spider suspension will lower the fs without reducing the output like the increased mass would do.
The added mass will lower the output of the woofer in the mass controlled upper frequencies, leaving output at the suspension controlled bass frequencies about the same.
A larger box or softer spider suspension will lower the fs without reducing the output like the increased mass would do.
The KEF B139 had a layer of aluminum foil/sheet bonded to its polystyrene cone way back in the late sixties, maybe they even knew about this then.
I though it was because the foil is shiny so the sound is projected off the cone better, giving the driver higher sensitivity and greater transient response, no?
Our friend Freedom666 experimented extensively with this on different drivers. He even gave his own recipe to try it.
I would indeed try on a cheap FR driver as wparks stated before contemplating something like a high efficiency pricey 15".
I would indeed try on a cheap FR driver as wparks stated before contemplating something like a high efficiency pricey 15".
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There is some theory on it but best is an A / B fast switching listening test with one driver modified, other one not and using balance on the preamp with a mono recording giving an impression what it does.
But the manual work for doing this DIY modification to a paper cone driver seems to be too demanding for most people as I rarely see someone investing time to do it.
For me its an ideal combination of materials for fullrange drivers lifting these with a sandwich cone and dsp control to a complete new level.
But already the one sided coating of paper cones with aluminum foil is worth a try.
But the manual work for doing this DIY modification to a paper cone driver seems to be too demanding for most people as I rarely see someone investing time to do it.
For me its an ideal combination of materials for fullrange drivers lifting these with a sandwich cone and dsp control to a complete new level.
But already the one sided coating of paper cones with aluminum foil is worth a try.
I like your answers.
This more about cone break-up. I think thin can work on paper cones, where the break up us earlier, this way having a paper cone tonality with no break up, sort of. Micro precision z studios drivers are like this
You know Cal that KEF was the first to use laser reflectometry on their speakers so your comment may not seem far off. They are definitely painted black..
Or just buy aluminum cone drivers and call it a day.
Likewise plenty of other drivers where strength has already been engineered into other cone materials
Likewise plenty of other drivers where strength has already been engineered into other cone materials
As you probably know, sensitivity and transient response are quite different things, however LOWERING mass can increase transient response.
INCREASING mass does lower LF resonance, but always at the expense of some efficiency over the broard range of the driver's response.
However in my eyes the alu paper alu tweak is underestimated.
If designed from scratch you could make a lighter cone with better properties (weight, stiffness, inner damping) as the same materials used seperately.
With the tweaking of existing paper cones inner damping and stiffness benefits remain.
As most fullrange drivers are conventionally built they profit a lot from better damping and stiffness.
If designed from scratch you could make a lighter cone with better properties (weight, stiffness, inner damping) as the same materials used seperately.
With the tweaking of existing paper cones inner damping and stiffness benefits remain.
As most fullrange drivers are conventionally built they profit a lot from better damping and stiffness.
I readed about this here 🙂) and then i saw these.
Here is a video showing how this works.
Is exactly how the stuff used in car audio for soundproofing works. Killmat.
My assumption is that the glue acts like a spring and the foil as the damper. This was stopping the extra resonances!
I found this very interesting
