Materials
You will need an umbrella with a vinyl cover. It cannot have a cloth top, because this will muffle sound. Get a tie-tac microphone. It will be easier to attach if it has a lapel clip. Repurpose an old paint roller handle. A basic 9-inch handle will work fine.
Instructions
Cut the plastic tip off of the top, outside of the umbrella. Slide the main handle of the paint roller through the hole that it creates. Clip the microphone on the end of the paint roller handle with the foam cover facing toward the inside of the umbrella. Attach the microphone to a recording device to monitor and record sound. More detailed instructions are a available in Make Magazine, Volume 14.
Opperation
Because the microphone is pointed toward the umbrella it picks up the sounds that are reflected. This allows it to pick up a greater number of sounds or more complex sounds equally, rather than only picking up the loudest or closest noises.