actually, studies have shown that adding electrics to soup cans does not improve the overall performance of the microphone. for an nice can mic, your best bet is to rap it in electric tape to reduce the overall THD. Also, studies shown that the soup can method is most beneficial to "screamo" and such music. The singer simply screams as hard as they can and the vibrations from the ridges in the can act as a catalyst to the exposed audio cables. New forms include the necessity of a new type of phantom power called "AC Line Imput Modular Processession" aka ALIMP. This is achieved by two ways:
1) using a pair of solid copper wires, solder one end to the bottem ridge of the can and another wire to the top rigde. Proceed in sticking the other ends into a 120v outlet.
2)perform as described, except use a 240v line where availible. The clarity and "punch" is terrific, it'll give you a shiver you've never experienced.