Have you tried "doping" your speaker cones?

FWIW everyone be careful with what you put on your cones, their was always a few at car audio shows that would use Armor-All on their speaker cones, big mistake, the stuff soaks in, weighs down the cone and essentially ruins the speaker. They make noise but it isn't very pleasant, I stick to light dusting with a dry towel/cloth. So moral of the story is if you aren't sure DON'T DO IT, you don't want a heavy flimsy cone!! well I assume you don't any way

~Tim

Twl,Damar varnish is not brand name,but a type of varnish typicaly used by artists who paint with oils. It would be available from an art supply store like "Daniel Smith" out of Seattle or from a company that makes art supplies like Windsor Newton.

I should mention that the main reason I tried it was to tame a small peak in the upper midrange and to take a little "edge" off the highs that was causing sibilance. You should try one thin coat at a time,let dry, and listen test. You can go too far with this and it can "deaden" the highs, if you are not careful. With woofers and mids, though, I think there is less risk of going too far,because of their lower frequency nature. It really stiffens the cone and creates better piston type action and reduces any cone breakup modes you may have. I should add that this is for paper cones only.

Everbody talks about light moving mass but many speaker manufaturers modify the drivers they use by adding damping material. An older Dalquast(sp) Moniter had some sort of putty on the front of the woofer. someone was marketing a doping mod for Mission 707s. One of the most highly rated speakers today use a "damping ring"(my term) applied to the back of magnesium mid-woofers.