tdshepard :
By the way, the correct expression is "sound damping," not "sound dampening." Yes I know that if you look up the definition it will say both are correct, but that's just because people have been mis-using them for so long. "Damping" means to dissipate energy. "Dampening" means to make something moist.
Well, if we're going to go to this degree of being pedantic, everyone should know that the issue lies not with the attached suffixes, but with the root word itself.
English is lovely, with its words-of-many-meanings and constantly-evolving-living-form. When taken into the context of mining, damp has another meaning that we don't see often in use.