Place the speaker inside one of the large plastic bags and set it onto the large pad.  (The large pad will absorb the low frequency vibrations of the speaker and prevent it from "walking" around the table).  Hook the speaker up the the Pyle amplifier and drive this with 21 to 31 Hz, from the wave generator.  A thin layer of the cornstarch mixture is all that is needed for this demonstration to be spectacular.  

The cornstarch mixture is made by adding 2 parts cornstarch to 1 part water.  (I usually start with this and then add small amounts of water to make this mixture quite soupy which seems to work much better when vibrating on the speaker).  You may also add some food coloring to make the mixture more visible when on dancing on the speaker.  For a very cool effect, add Fluorescein dye to the mixture to make it black light sensitive.