The cone soaking is a whole another subject all together. It is possible to make amassing changes with drivers, from taking the sound out off roof to complete killing sound. I know that effect Glycerin has to paper cone. There are hundreds of other comical compounds and method, starting from steaming the cones and ending with the deep soaking the cones in something like Chitine or floor polishers. I personally still prefer extensive way of dealing with drivers using better driver as is.
BTW, another candidate for a good direct radiator MF drives might be those new Feastrex Japanese drivers. If do not let them to run in extremes’ and do not peruse that foolish “full-range” idea then it might be interning. Still it is unknown to me how they sound and the most important how they might be integrated with other drivers (TAD 1201). It does not look like Greg around anymore but if he is it would be interesting to learn which direction he went.
"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche