I\'m looking for the most realistic way of playing sound of a rolling ball. Currently I\'m using a Wav sample that I play over and over as long as the ball is moving - which jus
I really like the approach described in this SIGGRAPH paper:
http://www.cs.ubc.ca/~kvdoel/publications/foleyautomatic.pdf
It describes synthesizing the sound of a rock rolling in a wok (no, really :). The idea is to use modal synthesis (i.e. convolved impulse responses), and the results can be very convincing.
Here's a link to the video demo that goes with the paper:
http://www.cs.ubc.ca/~kvdoel/publications/foleyautomatic.mpeg
And here's a link to the JASS library (written by one of the authors), which was used to create the sound for the video:
http://www.cs.ubc.ca/~kvdoel/jass/jass.html
I'm not sure if you could make it run on a smart phone, but with an efficient enough convolution routine/approximation you might be able to do something interesting...