Hi Wayne, I should clarify. I only damped the Alpha baskets using Dynamat. It's an asphalt based product with an adhesive back. It's used primarily in the autosound industry to dampen panels but also sees use in many electronic components. I was attempting to deaden the baskets a bit and control some of energy transfer from the cabinet back through the basket and motor assembly. I did not attempt to increase the mass of the cone to lower the resonant frequency. The Alpha works so good in the big cabinets, I just can't see messing with that. Definately try the clay on the exponential and report back.
P.S.Enjoying some Government Mule as I type. Take care! Jerrod