Woofer breakup question

[timc]

Hi all.

I have been looking at the data for alot of drivers, and i notice that very many have a notch in the response where the wavelength equals doubble the diameter of the cone. I know this is the result of the first breakup mode in the cone. The datasheet for the 2269 is a prime example.

On the other hand, the datasheet for the ME120 and teh 1200Fe shows little, to no notch at the corresponding frequencies.

Does anyone know how JBL have engineered their way around this problem?

A few thoughts i have had myself:

-Using ribbed cones, to reduce the amplitude of the breakup.
-Avoid use of straight conical diapraghm.


Any thoughts?


-Tim

[Robh3606]

Hello Timc

I would add aguaplas to that list. It adds mass and dampening.

Rob:)

[timc]

Hello Timc

I would add aguaplas to that list. It adds mass and dampening.

Rob:)


Ah. Of course. Just forgot to add it to the list. Thanks :)

However, i have seen several woofers with coating, that exhibits the "breakup dip". Does aquaplas do anything "more" than other coating materials?

I guess it is a combination of all the mentioned factors. I'm just looking to add to them, if there are any i have missed.

Cheers