Applausometer can be used in conjuction with a Syphon enabled software (thus it's limited to OS-X) to project and evaluate the "noise" of two goups of people.
It uses the core processing library minim and the Syphon library for Processing
With some software the Syphon output can be delivered upside-down, you can use a flip filter to adjust the image, it is the faster and lighter solution for this issue.
Tested with Processing 2.0.3