Recone materials & Thiele small

[rick57]

I’m considering buying an old guitar speaker that may prove it needs a new cone before too long - what scope there is to tweak TS params a little, and maybe improve control.

If a driver is reconed, and a different material to the original is used, am I right that:

If it's heavier material of similar stiffness, Fs will be lowered so the bottom end extended, but top end extension is likely to suffer?
~ If its lighter, vice versa?

If the material is stiffer, eg using Kevlar instead of the original paper, control may improve.

Thanks

[AndrewT]

Hi,
changing the cone will change the Voice coil, Surround, Spider, as well as the cone mass and stiffness.

These other changes will affect a number of parameters. Not just Fs.

I cannot confirm exactly which but likely changes are VAS, Fs, Mms, BL, Re, etc.

You could tweak to your advantage but just as easily go in some wrong directions.

Hopefully someone will post an exact list of changed parameters and how they relate to the basic cone/surround/voice coil.

[rick57]

Hi Andrew and all

I wasn’t thinking Fs would be the only change.
I am hoping to essentially get a feel for the likely change in “operating range”, from a change in material.

Thanks

Regards

[rick57]

So who's done recone?

Cheers

[Ron E]

do a search in this forum and find my driver design spreadsheet. You can plug in variables and see how the T/S params are changed.

[rick57]

Ron

I found your spreadsheet thanks. Diy dynamic driver

But it’s protected, so I can’t change anything w/out a password. .
And while it looks very handy, I can’t see that cone material is a factor.

Regards

[Ron E]

You don't expect me to give it away, do you It functions fine, you just can't see how it works. The red cells are changeable, as you no doubt have found out.

This spreadsheet only calculates T/S, which are essentially unaffected by cone material, other than the weight, which is variable.

Cone shape, cone material, and surround properties all affect the response above the range where this spreadsheet can predict ...

[clem_o]

Originally posted by rick57
Hi Andrew and all

I wasn’t thinking Fs would be the only change.
I am hoping to essentially get a feel for the likely change in “operating range”, from a change in material.

Thanks

Regards

One thing that can't be predicted and is extremely likely to change is the cone breakup frequency, as well as how gracefully the driver transitions into that frequency region and how annoying the cone breakup sound is.

Cheers!

almost forgot - reconing will also probably mean changing the surround material, causing more differences. Termination (affecting modals) , mechanical damping as well).

[rick57]

So what is known or predictable?

Who has read Colloms recently?

Cheers