I first would like to thank to my supervisor, Prof. Fabio Bellissima, for his careful guidance during my study years and for his friendship. I'll never forget our meetings in Siena. I also would like to thank my co-advisor, Prof. G. Corsi, for the continuous support given during these years. I am extremely grateful to Moreno Andreatta, Carlos Agon and Gerard Assyag, for hosting me at the Musical representations team at IRCAM and to Ichiro Fujinaga for hosting me at McGill University. Thanks to Juan Josè Burred, Philippe Esling, Arnaud Dessein and Niels Bogaards for reviewing and discussing the manuscripts and for their great friendship. Finally, I am really thankful to my great family: Bernardino, Ornella, Leonardo and Sara. Without them my life is completely meaningless; this work is dedicated to them.