A lot of people use a piezo but I found this to be to small to produce a good effect. I ran across a website Cymatics which had a link to a wave driver you could buy and after looking it over I realized it was just a modified speaker which could be easily made for cheap. This is my first instructable.
Step 1: Materials and tools and Misc
A discarded 8" speaker with its coil intact
small sink strainer
cardboard (an old cereal box)
heavy canvas (optional)
8-32 X 6" threaded rod (1)
3/8 X .171 X 1 Nylon spacer (1)
8-32 Insert Lock Nuts (4)
Metals spacers (4)
8-32 screws (8)
9 1/2" X 9 1/2" metal plate (cut from old VCR casing)
Sabre Saw with Sheet Metal Blade
This project involves cutting metal and plexiglass with a sabre saw, which can be dangerous.
Plexiglass is not easy to work with at this thickness. It cracks, shatters, and melts. You might want to use wood or metal instead of plexiglass.