SubDudes don't do much for the speaker itself as much as they prevent compliant wood floors from contributing to the sound.
Auralex subdude
I ordered the Subdudes, placed them under my Tekton Pendragons (full range) and thought "oh yaaa". What I had thought was really good became soo, soooo much better. This could go on forever but really, it's only about the basics of good sound. And these basic platforms deliver.