Taking the OF-2-Maya with Multi-forces two steps further. First off, it uses FFT and maps the distinctive characteristics from the audio to parameters of the forces. Finally, the location of the multi-force brush, if you will, is controlled by the centroid location of the face using the face-tracking magic of OF + ofOpenCV.
The code for this example plus other openFrameworks projects (ZCam, etc.) can be downloaded from my site: http://www.drwoohoo.com/.